JP4680537B2 - Surface emitting laser element, surface emitting laser array, optical interconnection system, optical communication system, electrophotographic system, and optical disc system - Google Patents

Description

  The present invention relates to a surface emitting laser element, a surface emitting laser array, an optical interconnection system, an optical communication system, an electrophotographic system, and an optical disc system.

  In recent years, surface emitting laser elements (surface emitting semiconductor laser elements) that generate laser oscillation in a direction perpendicular to the substrate have been intensively studied. The surface emitting laser has a low oscillation threshold current due to its small active layer volume compared to the edge emitting laser, the resonator structure is suitable for high-speed modulation, and has a circular high-quality outgoing beam shape. Because of these characteristics, it has attracted much attention as a high-speed optical communication light source such as a LAN and a light source of an electrophotographic system.

  Furthermore, the surface-emitting laser element can take out the laser output in the direction perpendicular to the substrate, so high-density two-dimensional array integration is easy, and its application to light sources for parallel optical interconnections, high-speed, high-resolution electrophotographic systems, etc. Has been.

  At present, as a typical structure of a surface emitting laser element, there are two types of structures of a selective oxidation type surface emitting laser element and an ion implantation type surface emitting laser element due to a difference in a constriction structure of an injection current. it can. In either structure, the oscillation threshold current is significantly reduced by confining the current injection region to a specific region corresponding to the central portion of the element.

For example, Non-Patent Document 1 discloses a 0.98 μm band surface emitting laser element using InGaAs as an active layer. In this surface emitting laser element, an Al _0.98 Ga _0.02 As selective oxidation layer is provided in an upper distributed Bragg reflector made of p-Al _0.9 Ga _0.1 As / GaAs provided on the active layer. Is provided. In this surface emitting laser element, after the crystal growth, the upper distributed Bragg reflector is etched into a rectangular mesa so that the side surface of the selectively oxidized layer is exposed by etching, and water heated to 85 ° C. is heated with nitrogen gas. In the bubbling atmosphere, the Al _0.98 Ga _0.02 As selective oxidation layer is selectively oxidized from the etching side surface toward the center of the mesa by heating to 425 ° C. By selective oxidation, an insulating region made of AlO _x (Al oxide) is formed around the mesa, and a conductive region made of a non-oxidized region is formed in the center of the mesa.

  As described above, the selective oxidation region in the surface emitting laser is usually performed by exposing a part of the AlGaAs selective oxidation layer to an atmosphere containing water vapor by etching or the like and heating it.

In this type of surface emitting laser element, holes injected from the surface of the upper distributed Bragg reflector are confined to the non-oxidation conducting region at the center of the mesa and injected into the active layer. AlO _x is a very good insulator, and the hole injection region can be limited to the central portion of the mesa. By using such a selective oxidation structure, the oscillation threshold current can be greatly reduced. Can do. In the element shown in Non-Patent Document 2, a low threshold current of 900 μm is obtained in an element in which the area of the non-oxidized region is 4.5 μm × 8 μm.

In addition, since the refractive index of AlO _x is about 1.6, which is lower than that of other semiconductor layers, in the selective oxidation type surface emitting laser element, the lateral refractive index difference in the resonator structure is caused by the selective oxidation layer. Since oscillating light is confined in the center of the mesa, loss due to diffraction can be reduced, and the efficiency of the element can be improved. However, since confinement of light increases, it is necessary to reduce the diameter of the oxidized constriction in order to suppress oscillation of higher-order transverse modes. Although depending on the wavelength band, conventionally, in a surface emitting laser element provided with a single oxidized constriction structure, the diameter or the length of one side of the oxidized constriction is reduced to about 3 to 4 times the oscillation wavelength. One fundamental mode oscillation can be obtained. As described above, by using the selective oxidation structure, it is possible to realize a reduction in oscillation threshold, a reduction in diffraction loss, and single fundamental mode control.

  On the other hand, the hydrogen ion implanted surface emitting laser element does not have a built-in waveguide structure like the selective oxidation type surface emitting laser element, and has a slight refractive index generated by heat generated when current is applied. A waveguide structure is formed by the change of (thermal lens effect) and the transverse mode is confined. Since the hydrogen ion implantation type surface emitting laser element has weak light confinement, it is possible to obtain single fundamental transverse mode oscillation even at a relatively large current confinement diameter. Non-Patent Document 3 shows a 0.85 mμm band hydrogen ion implanted surface emitting laser element using GaAs as an active layer. In the surface emitting laser element of Non-Patent Document 3, an oscillation threshold current of 2.5 mA is obtained by a hole injection region having a diameter of 10 μm.

  In many applications of surface emitting lasers, in addition to low threshold characteristics, a single-beam beam shape with high output is strongly required, and single transverse mode control is a very important issue. However, in the surface emitting laser device having the above structure, single fundamental transverse mode control is possible only when operating at a relatively low injection level, and in the case of a high injection level, by spatial hole burning of carriers. There is a problem that the high-order transverse mode oscillates.

  That is, during the high injection operation, the light density inside the resonator increases, so that a phenomenon (spatial hole burning phenomenon) occurs in which the stimulated emission rate of carriers in a region where the light intensity is high increases and the carrier density decreases. Since the fundamental transverse mode has a large mode distribution (electric field distribution) at the center of the mesa, the carrier density near the center of the mesa decreases as the current injection level increases and the optical density in the resonator increases. Saturation of the laser gain for the transverse mode occurs. On the other hand, in the region from the center to the side of the mesa, the carrier density is higher than that of the center of the mesa. Therefore, in the high-order transverse mode having the mode amplitude from the center of the mesa to the side, the laser gain is It increases and laser oscillation starts.

  This phenomenon occurs remarkably in a selective oxidation type surface emitting laser that is strongly confined in a transverse mode by a selective oxidation structure, and is a serious cause of deteriorating the emitted beam quality. In addition, since the surface-emitting laser element of the hydrogen ion implantation type does not have a built-in optical confinement structure, the stability to the transverse mode is poor, and the higher-order mode can easily be increased against the increase of the implantation level. Oscillates.

Various proposals have been made to solve the above-described problems by suppressing higher-order transverse mode oscillation. For example, Non-Patent Document 4 discloses a region corresponding to the current injection region at the center of the mesa. By selectively oxidizing the Al _0.9 Ga _0.1 As layer from the crystal growth surface and forming an anti-waveguide structure made of a selective oxidation structure in a part of the resonator structure, high-order transverse mode oscillation There is a description about the method of suppressing the above. In this example, in a 0.98 μm band device, a current confinement structure diameter of 10 to 17 μm provided by selectively oxidizing an 18.6 nm thick AlAs target oxidation layer from the etching side surface in a heated steam atmosphere. On the other hand, at a position corresponding to the current injection region in the central region of the mesa, an Al _0.9 Ga _0.1 As mixed crystal having a thickness of ½λ from the element surface is similarly formed in a heating atmosphere containing water vapor. By selectively oxidizing over a range of 15 μm and providing an anti-waveguide structure, a unimodal radiation pattern in which high-order transverse mode oscillation is suppressed is obtained even at an injection current 20 times the threshold.

  If the anti-waveguide structure is provided at the center of the resonator structure as in Non-Patent Document 4, the spatial overlap between the high-order transverse mode and the gain region (current injection region) in the active layer can be reduced. It is possible to suppress mode oscillation. FIGS. 3A and 3B are diagrams for explaining how the distribution of the fundamental transverse mode and the first-order higher-order mode is affected by the partially provided anti-waveguide structure. . Here, FIG. 3A is a diagram showing a mode distribution when there is no anti-waveguide structure, and FIG. 3B is a mode distribution when an anti-waveguide structure is partially provided at the center of the element. FIG. 3A and 3B show the basic transverse mode distribution, and the lower part shows the first-order higher-order transverse mode distribution. In the figure, a gain region generated by current injection is shown.

  As can be seen from FIGS. 3A and 3B, it is difficult for the fundamental transverse mode having a large mode distribution at the center of the mesa to push the mode distribution toward the side of the mesa by the anti-waveguide structure. In the high-order transverse mode, the electric field strength is zero at the center of the mesa and the region has a large mode distribution in the periphery, so the anti-waveguide structure can easily push the mode distribution in the lateral direction of the mesa. Yes, the mode distribution (electric field strength) at the center of the mesa can be reduced.

For the above reasons, by introducing the anti-waveguide structure, the gain for the high-order transverse mode is reduced, and the fundamental transverse mode operation up to a high output becomes possible. Furthermore, in the fundamental transverse mode, it is difficult to greatly expand the mode distribution, but it is considered that the electric field intensity at the center of the mesa can be expected to be flattened by the anti-waveguide structure. Therefore, it is considered that the electric field intensity distribution in the central part of the mesa is lowered and the occurrence of hole burning can be suppressed.
Applied Physics Letters vol. 66, no. 25, pp. 3413-3415, 1995, and Electronics Letters No. 24, Vol. 30, pp. 2043-2044, 1994 Electronics Letters No. 24, Vol. 30, pp. 2043-2044, 1994 Electronics Letters No. 5, Vol. 27, 1991, pp. 457-458 IEEE Photonics Technology Letters Vol. 10, no. 1, 1998, pp. 12-14

In the surface emitting laser element of Non-Patent Document 4 described above, in order to provide an anti-waveguide structure with AlO _x inside the resonator, selective oxidation of an AlGaAs layer having a large Al composition in a heated atmosphere containing water vapor (hereinafter simply referred to as water vapor). (Abbreviated as selective oxidation). The AlO _x layer provided to form the anti-waveguide needs to be provided at a position where the fundamental mode amplitude of the center part of the resonator is large, and therefore is oxidized from the etching end face of the mesa side face part like a conventional surface emitting laser. The method is not applicable. Therefore, selective oxidation is performed from the element surface. In addition, in order to obtain a sufficient effect on the higher-order mode by the anti-waveguide structure, the anti-waveguide structure needs to be formed at a position where the electric field strength is relatively large in the resonator. In the upper distributed Bragg reflector, It is necessary to make it. However, since epitaxial growth on AlO _x is difficult, a technique such as forming a laser structure by vapor deposition of a dielectric distributed Bragg reflector is necessary, and an extra dielectric vapor deposition step is required. Yes. Moreover, in order to inject current from the upper surface electrode portion, an extra step of removing the dielectric distributed Bragg reflector is required.

In addition, in the selective oxidation process in a heating atmosphere containing water vapor as described above, a selective oxidation layer that forms an anti-waveguide structure must always be provided on the surface of the element, which limits the degree of freedom in element design. There is a problem that. Furthermore, since the dielectric multilayer reflector is provided on the upper portion, the distance between the p-side electrode and the selective oxidation layer is close, and holes are formed from the outer peripheral portion of the AlO _x layer provided for forming the anti-waveguide structure. Since the injection is performed in the lateral direction toward the constricted region, there is a problem that the element becomes high resistance.

  In addition, in the optical fiber communication application and the writing light source application of the electrophotographic system, the polarization direction of the element needs to be controlled to a specific direction in addition to the high output operation in the single basic transverse mode. In other words, in high-speed optical fiber communication applications, the generation of noise caused by differences in reflection and transmission characteristics depending on the polarization direction of the optical components constituting the system is a problem. Similarly, in writing applications, there is a problem that the beam spot shape on the surface of the photoreceptor is distorted due to the polarization direction dependency of the optical system.

  However, in the above-mentioned known documents, there is no mention of control of the polarization direction, and it is considered difficult to obtain an element for practical use as it is. In addition, as an attempt to control the polarization direction, a method of forming an element on an inclined substrate and a method of applying an anisotropic stress to the element depending on processing conditions have been proposed. There is a problem that the range of growth conditions for crystal growth is narrow, and the latter method has a problem that the controllability of polarization depends on the controllability and reproducibility of processing conditions.

  The present invention increases the degree of freedom in device design, suppresses higher-order transverse mode oscillation more effectively, enables high-power operation in a single fundamental transverse mode, and controls the polarization direction to a specific direction. It is an object of the present invention to provide a surface emitting laser element, a surface emitting laser array, an optical interconnection system, an optical communication system, an electrophotographic system, and an optical disc system.

In order to achieve the above object, an invention according to claim 1 includes an active layer, a resonator spacer layer provided on both sides of the active layer, and a current confinement structure defining a current injection region to the active layer. And a pair of distributed Bragg reflectors facing each other with the active layer and the resonator spacer layer interposed therebetween, wherein the pair of distributed Bragg reflectors are AlGaAs-based. formed of a semiconductor material, further Oite in the semiconductor distributed Bragg reflector, a site having a spatial overlap in the current injection region and the laser resonance direction defined by the current confinement structure, containing an oxide of Al A region having a relatively low refractive index with respect to the periphery is provided.

According to a second aspect of the present invention, an active layer, a resonator spacer layer provided on both sides of the active layer, a current confinement structure that defines a current injection region to the active layer, the active layer and the resonance And a pair of distributed Bragg reflectors facing each other with a spacer spacer layer interposed therebetween, wherein the pair of distributed Bragg reflectors is an AlGaAs semiconductor in which the current confinement structure is formed by a high resistance region by ion implantation is made of a material, and have your further in the semiconductor distributed Bragg reflector, a site having a spatial overlap in the current injection region and the laser resonance direction defined by the current confinement structure, containing an oxide of Al, peripheral In contrast, a region having a relatively low refractive index is provided.

According to a third aspect of the present invention, there is provided an active layer, a current confinement structure that defines a current injection region into the active layer, and a pair of distributed Bragg reflectors that are opposed to each other with the active layer interposed therebetween. In the surface emitting laser device having a structure formed by selective oxidation, the surface emitting laser device includes an AlGaAs mixed crystal layer constituting a distributed Bragg reflector, and a part of the AlGaAs mixed crystal layer is formed by the current confinement structure. A portion of the AlGaAs mixed crystal layer having a spatial overlap in the laser resonance direction with the current injection region defined and having a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure contains oxygen. Peripheral regions where molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted by selective ion implantation of molecules and heat treatment after ion implantation. Respect is characterized in that forming the lower region relatively refractive index containing an oxide of Al.

According to a fourth aspect of the present invention, there is provided an active layer, a current confinement structure that defines a current injection region into the active layer, and a pair of distributed Bragg reflectors that are opposed to each other with the active layer interposed therebetween. In the surface emitting laser element having a structure formed by the high resistance region by ion implantation, the surface emitting laser element includes an AlGaAs mixed crystal layer constituting a distributed Bragg reflector, and a part of the AlGaAs mixed crystal layer includes: A portion of the AlGaAs mixed crystal layer having a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure, and a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure In this case, the selective ion implantation of molecules containing oxygen and the heat treatment after the ion implantation allow ion implantation of molecules containing oxygen in the same plane perpendicular to the laser resonance direction. The peripheral region which is not, is characterized in that forming the lower region relatively refractive index containing an oxide of Al.

According to a fifth aspect of the present invention, in the surface emitting laser element according to the third or fourth aspect, the ion implantation of molecules including oxygen in the same plane perpendicular to the laser resonance direction is not performed. On the other hand, a GaAs layer or a GaInP mixed crystal layer is provided in contact with the AlGaAs mixed crystal layer forming a region having a relatively low refractive index in the laser resonance direction.

According to a sixth aspect of the present invention, in the surface emitting laser element according to the third or fourth aspect of the present invention, in a peripheral region where oxygen-implanted molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted. On the other hand, the AlGaAs mixed crystal layer that forms the region having a relatively low refractive index is provided at a position corresponding to the antinode of the standing wave of the oscillation light in the resonator structure, and other elements constituting the element. It is characterized by relatively high doping compared to the AlGaAs mixed crystal layer.

According to a seventh aspect of the present invention, in the surface-emitting laser element according to any one of the first to sixth aspects, the region having a relatively low refractive index is a pair of distributed Bragg reflectors. The n-type distributed Bragg reflector is provided.

According to an eighth aspect of the present invention, in the surface emitting laser element according to any one of the first to seventh aspects, a spatial overlap is provided in the laser resonance direction with the laser resonance region. A high refractive index region having a higher refractive index than the region having a relatively low refractive index is provided around the region having a relatively low refractive index, and further, the high refractive index is provided around the high refractive index region. A cladding region having a low refractive index with respect to the refractive index region is provided.

The invention according to claim 9 is characterized in that, in the surface emitting laser element according to claim 8 , anisotropy is provided in the width of the high refractive index region surrounded by the cladding region.

According to a tenth aspect of the present invention, in the surface emitting laser element according to the eighth aspect, the clad region is provided only in a pair of directions perpendicular to a laser resonance direction facing each other across the laser resonance region. It is characterized by.

According to an eleventh aspect of the present invention, in the surface emitting laser device according to any one of the first to tenth aspects, the relative refractive index provided with a spatial overlap with the laser resonance region. The region having a low is characterized by having an anisotropic shape.

According to a twelfth aspect of the present invention, in the surface-emitting laser element according to any one of the first to eleventh aspects, the active layer is composed of a group III-V element, and the group III constituting the active layer. It is characterized in that any or all of Ga and In are included as an element, and any or all of As, N, Sb, and P are included as a group V element.

A thirteenth aspect of the present invention is a surface emitting laser array comprising the surface emitting laser elements according to any one of the first to twelfth aspects arranged in an array. is there.

In the invention described in claim 14, the surface emitting laser element according to any one of claims 1 to 12 or the surface emitting laser array according to claim 13 is used as a light source. This is an optical interconnection system that is characterized.

In the invention described in claim 15, the surface-emitting laser element according to any one of claims 1 to 12 or the surface-emitting laser array according to claim 13 is used as a communication light source. Is an optical communication system.

According to a sixteenth aspect of the present invention, the surface emitting laser element according to any one of the first to twelfth aspects or the surface emitting laser array according to the thirteenth aspect is used as a light source for writing. It is an electrophotographic system characterized by things.

According to a seventeenth aspect of the present invention, the surface emitting laser element according to any one of the first to twelfth aspects or the surface emitting laser array according to the thirteenth aspect is used as a light source for reading / writing. It is an optical disc system characterized by that.

According to the first aspect of the present invention, in the oxidation type surface emitting laser element in which the current injection region is defined by the selective oxidation current confinement layer, the portion of the semiconductor distributed Bragg reflector is overlapped with the laser oscillation region. By providing a low refractive region made of oxide, a selective oxidation surface emitting laser element having an anti-waveguide structure with low manufacturing cost, high element design freedom, and low element resistance is provided. can do.

  That is, according to the first aspect of the present invention, in the selective oxidation surface emitting laser element having an anti-waveguide structure made of an Al oxide, the degree of freedom in designing the element can be increased more effectively. It is possible to provide an element capable of high-power operation in a single fundamental transverse mode in which the next transverse mode oscillation is suppressed.

According to the second aspect of the present invention, in the hydrogen ion implantation type surface emitting laser device in which the current injection region to the active layer is defined by the high resistance region by ion implantation , the laser oscillation in the semiconductor distributed Bragg reflector is performed. By providing a low-refractive region made of an Al oxide in a region that overlaps with the region, the element can be designed with a high degree of freedom in design, and the resistance of the device is low. A hydrogen ion implantation surface emitting laser element having a structure can be easily obtained.

  That is, according to the second aspect of the present invention, in the hydrogen ion implantation surface emitting laser element having an anti-waveguide structure made of an Al oxide, the degree of freedom in designing the element can be increased more effectively. It is possible to provide an element capable of high output operation in a single fundamental transverse mode in which high-order transverse mode oscillation is suppressed.

  According to the invention described in claim 3, the surface emitting laser capable of increasing the degree of design freedom of the element, suppressing higher-order transverse mode oscillation more effectively, and capable of high output operation in a single fundamental transverse mode. An element can be provided.

  In the element of the prior art of Non-Patent Document 4, as a method of providing an anti-waveguide structure, a method of providing a low refractive index region containing an Al oxide near the laser oscillation region is used. After the cavity spacer layer and the distributed Bragg reflector are partially formed of a semiconductor material, the semiconductor layer containing Al in the element surface is oxidized by selective oxidation in a water vapor atmosphere, and laser oscillation is performed. A low refractive index region made of an oxide of Al is provided in a region having a spatial overlap in the region.

  Accordingly, an oxide region is formed on the element surface during the formation of the element portion, and it is difficult to subsequently perform crystal growth of the semiconductor material. For this reason, the element of the prior art uses a configuration in which the upper reflecting mirror is a dielectric distributed Bragg reflector. However, when the dielectric distributed Bragg reflector is used, the current injection path is limited, the resistance of the element tends to increase, and a dielectric deposition apparatus is required in addition to the semiconductor material growth apparatus. The process of forming the distributed Bragg reflector, which requires precise film thickness control, must be performed by two different apparatuses, resulting in increased manufacturing costs.

  Such problems in the prior art can be solved by forming an oxidized region inside the semiconductor structure without oxidizing the outermost surface of the device. As such a method, for example, the device surface In this method, oxygen ion implantation is performed, and then a heat treatment is performed to selectively oxidize only the region into which oxygen ions are implanted inside the device.

That is, according to the invention of claim 3, oxygen ions are implanted by subjecting the low refractive index layer necessary for forming the anti-waveguide structure to oxygen ion implantation from the crystal growth surface and then heat treatment. It is possible to selectively form the performed region. As described above, it is possible to oxidize an AlGaAs mixed crystal by performing heat treatment after oxygen ion implantation or ion implantation of molecules containing oxygen, as disclosed in JP-A-9-27650 or JP-A-2002-289967. It is disclosed in the publication. The AlGaAs mixed crystal has a larger Al composition and is more likely to be oxidized, and the GaAs layer is hardly oxidized. In these known techniques, in a device in which crystal growth has been completed, it is disclosed as a technology for oxidizing AlGaAs outside the resonance region to create a waveguide structure in the resonator. All membranes are selectively oxidized. However, in these known techniques, there is no mention regarding the formation of an anti-waveguide structure and the regrowth after crystal growth. On the other hand, when the AlGaAs layer is oxidized by oxygen ion implantation as described above, the ion implantation depth and the thickness of the layer to be selectively oxidized are not exposed to a heating atmosphere containing water vapor as in the conventional device. By selecting the ion implantation area, it is possible to selectively oxidize the AlGaAs layer at a desired location in the epi structure. Therefore, unlike the prior art device, there is no need to oxidize after exposing the AlGaAs layer on the device surface, and no AlO _x layer is formed on the device surface. By recovering, the element portion can be grown again with good crystallinity. Therefore, it is possible to easily form an anti-waveguide structure in an arbitrary region inside the element structure, and the degree of freedom in design is dramatically increased. In addition, the oxide structure for forming the anti-waveguide structure at the center of the mesa only needs to have a relatively low refractive index as compared with the peripheral region, so that the AlGaAs mixed crystal is not necessarily completely oxidized. Absent. In other words, the amount of oxygen ions implanted can be adjusted so that a desired refractive index change can be obtained for the design. As described above, there is an effect that the degree of freedom in designing a surface emitting laser having an anti-waveguide structure with a low refractive index layer becomes very large.

  Thus, in the invention of claim 3, in the current confined surface emitting laser by selective oxidation, the anti-waveguide structure is formed by ion implantation of molecules containing oxygen and selective oxidation of AlGaAs mixed crystal by heat treatment. Thus, it is possible to easily form an anti-waveguide structure in an arbitrary region inside the element structure. As a result, the degree of freedom in element design is increased, and an element capable of high output operation in a single fundamental transverse mode in which high-order transverse mode oscillation is suppressed more effectively can be obtained.

According to the invention of claim 4, the active layer, a current confinement structure that defines a current injection region to the active layer, and a pair of distributed Bragg reflectors facing each other across the active layer, In a surface emitting laser element in which a current confinement structure is formed by a high resistance region by ion implantation, the surface emitting laser element includes an AlGaAs mixed crystal layer constituting a distributed Bragg reflector , and a part of the AlGaAs mixed crystal layer Has a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure, and an AlGaAs mixed crystal layer having a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure. This is because the oxygen ions containing molecules in the same plane perpendicular to the laser resonance direction are obtained by selective ion implantation of molecules containing oxygen and heat treatment after ion implantation. The peripheral region where entrance is not made, since the forming area of low relative refractive index that includes an oxide of Al, and the degree of freedom in designing the device, effectively higher-order transverse modes It is possible to provide a surface emitting laser element in which oscillation is suppressed and high power operation is possible in a single fundamental transverse mode.

  That is, as in the fourth aspect of the invention, also in the ion-implanted surface-emitting laser element in which current confinement is performed by the high resistance region by hydrogen ion implantation, as in the case of the third aspect of the invention, any element inside the element structure Thus, it is possible to easily form an anti-waveguide structure in this region, and the effect of increasing the degree of freedom in design can be obtained.

  Since the hydrogen ion implantation surface emitting laser element does not have a built-in waveguide structure, the mode distribution can be easily changed by a slight change in refractive index. Therefore, when the anti-waveguide structure is provided in the resonator, it is possible to move the region of the high-order transverse mode, which has a large mode amplitude, to the outside of the current injection region (gain region) very effectively. It is possible to suppress higher-order transverse mode oscillation more effectively.

  In the hydrogen ion implantation surface emitting laser element, since the optical confinement in the lateral direction is weak, even with a relatively large current confinement diameter, it oscillates in a single fundamental transverse mode, but there is no built-in waveguide structure, There is a problem that the transverse mode is unstable and the higher-order mode easily oscillates as the injection level increases. However, by forming a slightly anti-waveguide structure partially as in claim 4, it is possible to easily move the region having a large mode amplitude in the high-order transverse mode away from the gain region. In addition, the hydrogen ion-implanted surface-emitting laser has an advantage that a high-power operation can be easily obtained because the current confinement diameter can be increased as compared with the oxidized constriction-type surface-emitting laser element as described above. Since the hydrogen ion implantation surface emitting laser does not have a built-in waveguide structure, even a very small difference in refractive index has a large effect on the mode distribution, thus reducing the influence on the fundamental transverse mode. Therefore, it is desirable to provide the anti-waveguide structure at a position far from the active region where the light intensity is large. Further, when the anti-waveguide structure is provided by oxygen ion implantation and heat treatment as in claim 4, the change in the refractive index can be suppressed by adjusting the amount of oxygen ions to be implanted.

  As described above, in the invention of claim 4, in the hydrogen ion implanted surface emitting laser element, high-order transverse mode oscillation is particularly effectively suppressed, and high output is obtained in single fundamental transverse mode oscillation.

According to a fifth aspect of the present invention, in the surface emitting laser element according to the third or fourth aspect of the present invention, the periphery in which the ion implantation of molecules including oxygen in the same plane perpendicular to the laser resonance direction is not performed. Since the GaAs layer or the GaInP mixed crystal layer is provided in contact with the AlGaAs mixed crystal layer, which forms a region having a relatively low refractive index with respect to the region, in the laser resonance direction, it is possible to limit the oxidized region. It is possible to adjust the phase condition more precisely.

  In general, in ion implantation, implanted ions have a continuous distribution having a peak at a certain implantation depth in accordance with an acceleration voltage. For example, when the acceleration voltage is reduced and the implantation peak position is shallow, a steep implantation profile can be obtained, and only the AlGaAs mixed crystal layer at a desired position can be easily selectively oxidized. However, when ion implantation is performed to a certain depth or more, the width of the implantation profile becomes wide, and the oxidation extends to the AlGaAs before and after the AlGaAs layer to be selectively oxidized, and the refractive index changes. Occurs. The thickness of the AlGaAs layer in the anti-waveguide structure is preferably set so that the refractive index value after oxidation satisfies the multiple reflection phase condition of the Bragg reflector. Is undesirable because it reduces the reflectivity of the Bragg reflector. However, as in claim 5, a GaInP mixed crystal layer, a GaAs layer, or a GaInP / GaAs distributed Bragg reflector (semiconductor structure) adjacent to a Bragg reflector including an AlGaAs layer to be selectively oxidized. By providing this, the oxidation region can be limited, and the phase condition can be adjusted more precisely. GaInP can be crystal-grown by lattice matching with a GaAs substrate. Further, since Al does not contain Al as a constituent element, oxidation hardly proceeds even when oxygen ion implantation is performed. Therefore, even when there is a distribution in the implanted ion width, it is possible to oxidize only the AlGaAs layer in a specific region. In addition, by oxidizing only AlGaAs at a desired position in this way, it is very easy to precisely adjust the reflection wavelength of the distributed Bragg reflector in the center of the mesa (reflection wavelength for the fundamental transverse mode) with good controllability. Thus, an element having excellent element characteristics such as the oscillation threshold characteristic can be obtained.

According to a sixth aspect of the present invention, in the surface emitting laser element according to the third or fourth aspect of the present invention, the periphery in which the ion implantation of molecules including oxygen in the same plane perpendicular to the laser resonance direction is not performed. The AlGaAs mixed crystal layer that forms a region having a relatively low refractive index with respect to the region is provided at a position corresponding to the antinode of the standing wave of the oscillation light in the resonator structure and constitutes an element. Compared with other AlGaAs mixed crystal layers, it is doped at a relatively high concentration, so that it is possible to more effectively suppress higher-order transverse mode oscillation and obtain an element capable of high output operation in a single fundamental transverse mode. I can do things.

A highly doped semiconductor exhibits significant light absorption due to free carrier absorption and the like. In addition to this, the p-type semiconductor has absorption between valence bands, and therefore has a property of increasing absorption particularly for light having a long wavelength. If an AlGaAs layer forming a low refractive index region is doped at a high concentration with respect to the surrounding AlGaAs layer during crystal growth by selective oxidation by oxygen ion implantation and heat treatment, free carrier absorption or intervalence band absorption by this layer is performed. The absorption loss due to can be increased. However, at the site where oxygen ion implantation has been performed, an AlO _x insulator is formed by the heat treatment and changes transparently with respect to the oscillation wavelength, so that the basic lateral region having a large mode amplitude at the center of the mesa (ion implantation region). Absorption loss for the mode is eliminated, and absorption occurs only for the high-order transverse mode having a large mode amplitude from the center to the side of the mesa. Therefore, it is possible to suppress the oscillation of the high-order transverse mode by increasing the absorption loss.

  In addition, the standing wave of the oscillation light in the distributed Bragg reflector has a distribution in which nodes and antinodes of the electric field are repeated every optical thickness ¼λ. In the nλ resonator, AlGaAs (when viewed from the resonator side) The interface from the low refractive index layer) to GaAs (high refractive index layer) is the node of the electric field, and conversely, the interface from GaAs to AlGaAs is the antinode of the electric field. When a highly doped AlGaAs layer is provided at the position corresponding to the antinode of the standing wave, and the AlGaAs layer in the area corresponding to the center of the oscillation region is selectively oxidized by oxygen ion implantation and heat treatment, the light at the antinode position is Corresponding to the high electric field intensity, the amount of absorption for the high-order transverse mode can be further increased. Therefore, it is possible to obtain a larger suppression effect of the high-order transverse mode.

According to a seventh aspect of the present invention, in the surface emitting laser element according to any one of the first to sixth aspects, the region having a relatively low refractive index is a pair of distributed Bragg reflectors. Therefore, it is possible to obtain an element capable of high output operation in a single fundamental transverse mode with reduced element resistance.

  A p-conductivity type semiconductor originally has a high resistance because the carrier mobility is about an order of magnitude smaller than that of an n-conductivity type semiconductor. As in Non-Patent Document 4 described above, when an oxide region for forming an anti-waveguide structure is provided in a p-conductivity type semiconductor so as to overlap with a conduction region due to a current confinement structure, this region has a high resistance. After the holes have bypassed the region, the holes are further confined to the center of the mesa by the current confinement structure and injected. Therefore, the p-conductivity type semiconductor having a long and narrow current path and a low mobility is likely to have a high resistance.

On the other hand, when the anti-waveguide structure is provided in the n-conductivity type distributed Bragg reflector as in claim 7 , there is no current confinement structure between the anti-waveguide structure and the active layer, and the movement of electrons originally. Because of the high degree of resistance, even if there is an insulating (or high resistance) region in the center of the mesa, the increase in resistance is very small, and it is possible to keep the element resistance at the same level as conventional elements. is there. In the device of the present invention, an anti-waveguide structure can be formed inside the epi structure by oxygen ion implantation and heat treatment. Unlike the conventional device in which selective oxidation is performed from the surface portion in a heated atmosphere containing water vapor, AlO is formed on the surface portion. _{Since x} is not formed, the crystal can be regrown, and the above-described structure can be easily formed. The anti-waveguide structure has almost the same effect on the transverse mode regardless of whether it is provided in the p-conductivity type distributed Bragg reflector or the n-conductivity type distributed Bragg reflector. The effect of suppressing can be obtained. Further, by suppressing the increase in element resistance, heat generation can also be suppressed, so that a higher output operation is possible.

  In the present invention, as described above, an element capable of high output operation in the single basic transverse mode can be obtained.

According to the eighth aspect of the present invention, the oxidation of Al is performed by surrounding the relatively low refractive index region provided in a direction perpendicular to the laser resonance direction and having a spatial overlap with the laser resonance region. By providing a cladding region with a relatively low refractive index relative to the periphery including objects, light leakage (diffraction) loss in the direction perpendicular to the laser resonance direction is prevented, and a single output up to a higher output is achieved. Basic transverse mode oscillation is possible.

That is, according to the eighth aspect of the present invention, in the surface emitting laser element having an anti-waveguide structure made of an Al oxide, high-order transverse mode oscillation is more effectively suppressed by providing the cladding region. In addition, it is possible to provide an element capable of high output operation in the single basic transverse mode.

According to a ninth aspect of the present invention, in the surface emitting laser element according to the eighth aspect, the anisotropy is provided in the width of the high refractive index region surrounded by the cladding region, so that the laser oscillation light The polarization direction is controlled to a specific direction, and single fundamental transverse mode oscillation up to a higher output becomes possible.

That is, according to the ninth aspect of the present invention, in the surface emitting laser element having the anti-waveguide structure by the oxide of Al, by providing the cladding region having the anisotropic shape, it is possible to more effectively It is possible to provide an element capable of high power operation in a single fundamental transverse mode in which mode oscillation is suppressed and the polarization direction is controlled in a specific direction.

According to a tenth aspect of the present invention, in the surface emitting laser element according to the eighth aspect, the clad region is provided only in a pair of directions perpendicular to the laser resonance direction facing each other across the laser resonance region. (I.e., a structure in which a low refractive index region, i.e., a cladding region, made of an oxide of Al provided outside the region centered on the laser oscillation region is provided only in a pair of opposing directions across the laser resonance region; As a result, the polarization direction is controlled to a specific direction, and a single fundamental transverse mode operation up to a higher output becomes possible.

That is, according to the invention described in claim 10, in the surface emitting laser element having the anti-waveguide structure by the oxide of Al, by providing the cladding region having the anisotropic shape, the higher order It is possible to provide an element capable of high output operation in a single fundamental transverse mode in which transverse mode oscillation is suppressed and the polarization direction is controlled in a specific direction.

According to an eleventh aspect of the present invention, in the surface-emitting laser element according to any one of the first to tenth aspects, the relatively provided with a spatial overlap with a laser resonance region. The region having a low refractive index has an anisotropic shape (that is, a low refractive index due to an Al oxide provided with a spatial overlap in the laser oscillation region in order to form an anti-waveguide structure). (By making the refractive index region an anisotropic shape such as a rectangular or elliptical shape), the polarization of the laser oscillation light is controlled in a specific direction, and a single fundamental transverse mode up to a higher output Operation is possible.

That is, according to the invention described in claim 11, in the surface emitting laser element having the anti-waveguide structure of the Al oxide, the low refractive index region provided for forming the anti-waveguide structure is formed in an anisotropic shape. Thus, it is possible to provide an element capable of high-power operation in a single fundamental transverse mode in which higher-order transverse mode oscillation is further effectively suppressed and the polarization direction is controlled to a specific direction.

According to a twelfth aspect of the present invention, in the surface-emitting laser element according to any one of the first to eleventh aspects, the active layer is composed of a group III-V element to constitute the active layer. As the group III element, any or all of Ga and In are included, and as the group V element, any or all of As, N, Sb, and P are included, and as the active layer material By using the above materials, a surface emitting laser element having an oscillation wavelength of 1.1 μm to 1.6 μm can be obtained on a GaAs substrate. On the GaAs substrate, it is possible to use a distributed Bragg reflector made of an AlGaAs mixed crystal having excellent characteristics, and an element having excellent characteristics can be obtained. Further, among these materials, a GaInNAs material obtained by adding a trace amount of nitrogen of GaInAs or a few percent or less has a large conduction band discontinuity with respect to a barrier layer such as GaAs, and the same wavelength band element on a conventional InP substrate. Has better temperature characteristics. Furthermore, since the single transverse mode oscillation can be obtained up to a high output by providing the configuration according to the first to twelfth aspects, the coupling efficiency to an optical fiber or the like is particularly high. From the above, it has the effect of obtaining a surface emitting laser element suitable for optical fiber communication.

According to a thirteenth aspect of the present invention, the surface emitting laser is characterized in that the surface emitting laser elements according to any one of the first to twelfth aspects are arranged in an array. Since it is an array, it is possible to provide a surface emitting laser array capable of high power operation in a single fundamental transverse mode. That is, according to the invention of claim 13 , it is possible to obtain a surface emitting laser array with good beam quality capable of fundamental transverse mode oscillation up to a high output. Therefore, the surface emitting laser array according to the present invention is suitable as a light source for a multi-beam writing system of an electrophotographic system or a long-distance optical communication system.

According to the invention described in claim 14, the surface emitting laser element according to any one of claims 1 to 12 or the surface emitting laser array according to claim 13 is used as a light source. Therefore, it is possible to provide a highly reliable optical interconnection system.

  That is, in the surface emitting laser element and the surface emitting laser array according to the present invention, since the oscillation can be obtained up to a high output in the fundamental transverse mode, the coupling with the optical fiber is high. Further, since higher-order transverse mode oscillation is suppressed, even when the operating state of the element such as the output changes, the coupling rate changes and the optical input to the fiber changes very little. Therefore, a highly reliable optical interconnection system can be provided.

According to the invention described in claim 15, the surface emitting laser element according to any one of claims 1 to 12 or the surface emitting laser array according to claim 13 is used as a communication light source. Therefore, a highly reliable optical communication system can be provided.

  That is, in the surface emitting laser element and the surface emitting laser array according to the present invention, since the oscillation can be obtained up to a high output in the fundamental transverse mode, the coupling with the optical fiber is high. Further, since higher-order transverse mode oscillation is suppressed, even when the operating state of the element such as the output changes, the coupling rate changes and the optical input to the fiber changes very little. Further, since a higher output can be obtained than in the conventional case, long-distance communication is possible. Therefore, a highly reliable optical communication system can be provided.

According to the invention described in claim 16, the surface emitting laser element according to any one of claims 1 to 12 or the surface emitting laser array according to claim 13 is used as a light source for writing. Therefore, it is possible to provide a low-cost, high-definition electrophotographic system.

  That is, the conventional surface emitting laser element has a small output and is difficult to use as a writing light source for an electrophotographic system. However, the surface emitting laser element and the surface emitting laser array of the present invention have a high output in the basic transverse mode. Oscillation can be obtained. Therefore, it can be used as a light source for writing in an electrophotographic system. In addition, when a surface emitting laser element is used as a writing light source in an electrophotographic system, the beam is easily formed because the emitted beam is circular. Furthermore, since the position accuracy between the arrays is high, a plurality of beams can be easily condensed with high reproducibility using the same lens. Therefore, the optical system is simple, and a high-definition system can be obtained at low cost. Further, since the surface emitting laser element of the present invention has a large output, high speed writing is possible particularly when an array is used. As described above, the present invention can provide a low-cost and high-definition electrophotographic system.

According to the invention described in claim 17, the surface-emitting laser element according to any one of claims 1 to 12 or the surface-emitting laser array according to claim 13 is used as a light source for reading / writing. Since the optical disc system is characterized in that it is used, it is possible to provide an optical disc system with excellent reliability and capable of high-speed access (high-speed reading and writing).

That is, the conventional surface emitting laser element has a small output in single fundamental transverse mode oscillation, and is difficult to use as a light source of an optical disk system. However, in the surface emitting laser element and the surface emitting laser array of the present invention, the fundamental transverse mode is used. Thus, oscillation can be obtained stably up to high output. Therefore, it can be used as a light source for writing in an optical disc system, and a highly reliable optical disc system can be configured. Further, by using a surface emitting laser array, high-density reading and writing are possible, and a high-speed optical disk system can be configured. As described above, according to the present invention, it is possible to provide an optical disc system with excellent reliability and capable of high-speed access (high-speed reading and writing).

  Hereinafter, the best mode for carrying out the present invention will be described.

(First form)
The first aspect of the present invention includes an active layer, a resonator spacer layer provided on both sides of the active layer, a current confinement structure that defines a current injection region into the active layer, the active layer, and the resonator And a pair of distributed Bragg reflectors facing each other with a spacer layer interposed therebetween, wherein the pair of distributed Bragg reflectors is made of a semiconductor material, and the current confinement structure is formed by selective oxidation. In a semiconductor distributed Bragg reflector or resonator spacer layer, the region containing a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure includes an Al oxide, and the periphery. In other words, a region having a relatively low refractive index is provided.

  In the surface emitting laser element of the prior art, the distributed Bragg reflector located above the Al oxide is formed of a dielectric material. Since the dielectric is an insulator, the distributed Bragg material used for this material is used. The reflector cannot be energized through the distributed Bragg reflector. Therefore, a surface emitting laser element using a dielectric distributed Bragg reflector is, for example, a distributed Bragg reflector or a contact layer provided inside the element, like a surface emitting laser element having an anti-waveguide structure of the prior art. It is necessary to have an intracavity contact structure for injecting current into the active region. However, in general, the intracavity contact structure has a problem that current injection is performed from the peripheral portion of the element through a thin contact layer, and the resistance of the element is easily increased. As described above, in general, an element using a dielectric distributed Bragg reflector has a problem that a current injection path is greatly restricted, and the resistance of the element is easily increased.

  On the other hand, in the configuration of the first embodiment of the present invention, a distributed Bragg reflector including a low refractive region made of Al oxide, which is provided to form an anti-waveguide structure, is made of a semiconductor material. Therefore, for example, like a conventional selective oxidation type surface emitting laser element, it is possible to inject current from the contact layer provided on the top of the element toward the substrate. In addition, even when there is an insulating region made of an oxide of Al at the center of the device, current injection can be performed through a region having a relatively large area around the periphery, so that the resistance of the device is increased. Can be prevented. In this way, current injection through the distributed Bragg reflector is possible, and the influence on the element resistance is small compared to the conventional anti-waveguide type surface emitting laser element, so that a high degree of freedom in device design can be obtained. Can do.

  In addition, the distributed Bragg reflector is required to have a very precise film thickness precision, and it is necessary to closely control the film forming rate. Therefore, performing the film forming process of the distributed Bragg reflector by using two types of apparatuses having different materials and methods complicates the manufacturing process and increases the manufacturing cost. On the other hand, in the configuration of the first embodiment, the distributed Bragg reflector can be grown at once by a semiconductor material crystal growth apparatus such as an MOCVD apparatus, and the manufacturing process can be simplified. it can.

  As described above, it is possible to provide a selective oxidation surface emitting laser element having a semi-waveguide structure with low manufacturing cost, high degree of freedom in element design, and low element resistance.

(Second form)
According to a second aspect of the present invention, there is provided an active layer, a resonator spacer layer provided on both sides of the active layer, a current confinement structure that defines a current injection region to the active layer, the active layer, and the resonator And a pair of distributed Bragg reflectors facing each other with a spacer layer interposed therebetween, wherein the pair of distributed Bragg reflectors is made of a semiconductor material, wherein the current confinement structure is formed by a high resistance region by ion implantation Further, in the semiconductor distributed Bragg reflector or resonator spacer layer, an oxide of Al is included in a portion having a spatial overlap in the laser resonance direction with the current injection region defined by the current confinement structure. A region having a relatively low refractive index with respect to the periphery is provided.

  As described in the first embodiment, in the conventional anti-guided surface-emitting laser element, it is located above a low refractive index region made of an oxide of Al provided to form an anti-waveguide structure. Since the distributed Bragg reflector is made of a dielectric material, there is a limitation that current cannot be injected from above the dielectric distributed Bragg reflector.

  On the other hand, the surface emitting laser element according to the second embodiment can be energized by forming a distributed Bragg reflector including a low refraction region made of Al oxide with a semiconductor material. In addition, the conventional hydrogen ion implantation surface emitting laser element has a high resistance region formed by hydrogen ion implantation after the element portion is formed of a semiconductor material. However, in the configuration of the anti-waveguide type surface emitting laser device using a dielectric mirror as in the prior art, the current injection is performed below the dielectric mirror. Therefore, it is difficult to make such a simple configuration. In addition, in order to inject current from below the dielectric mirror, for example, it is necessary to have an intracavity contact type structure, so there is a problem that the resistance of the element is easily increased as described above. In addition, it is difficult to infer the configuration of a hydrogen ion-implanted surface emitting laser element having an anti-waveguide structure from the configuration of the anti-waveguide surface emitting laser element using selective oxidation according to the prior art.

  In the configuration of the second embodiment, the distributed Bragg reflector including the oxide of Al or the resonator spacer layer is formed of a semiconductor material, so that the distributed Bragg is similar to the description of the configuration and operation of the first embodiment. Current injection from the upper surface of the reflector is possible, and an element having an anti-waveguide structure can be obtained with a very simple configuration like a conventional hydrogen ion implantation surface emitting laser element. In addition, since current can be injected from the upper surface of the element, it is possible to prevent the resistance from being increased as in the first embodiment.

  As described above, it is possible to provide a hydrogen ion-implanted surface emitting laser element having a semi-waveguide structure with a high degree of design freedom and a low element resistance.

(Third form)
A third embodiment of the present invention includes an active layer, a current confinement structure that defines a current injection region into the active layer, and a pair of distributed Bragg reflectors that are opposed to each other with the active layer interposed therebetween, and has a current confinement structure. In the surface emitting laser element formed by selective oxidation, the surface emitting laser element includes an AlGaAs mixed crystal layer, and a part of the AlGaAs mixed crystal layer includes a current injection region defined by the current confinement structure and a laser. A portion of the AlGaAs mixed crystal layer having a spatial overlap in the resonance direction and defined by the current confinement structure and a spatial overlap in the laser resonance direction is formed by selective ion implantation of molecules including oxygen. A region having a relatively low refractive index with respect to a peripheral region where oxygen-implanted molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted by heat treatment after ion implantation. It is characterized in that to form a.

  In the configuration of the third embodiment, the AlGaAs mixed crystal in the region where the ion implantation of oxygen-containing molecules has been performed is oxidized by the heat treatment and the refractive index becomes lower than that in the peripheral region, and is anti-guided to a part inside the resonator. A structure is formed. When the anti-waveguide structure is formed by ion implantation of molecules containing oxygen and selective oxidation by heat treatment instead of the conventional selective oxidation in a heating atmosphere containing water vapor as in the first embodiment, An anti-waveguide structure can be formed at an arbitrary place. Further, unlike the prior art, it is not necessary to expose the surface of the AlGaAs layer to the heated water vapor atmosphere for oxidation, and therefore, no oxide layer is formed on the element surface, so that regrowth is possible. Therefore, the degree of freedom in element design increases, and an element structure excellent in suppressing higher-order transverse modes can be realized.

  In addition, if an anti-waveguide structure is partially provided in the center of the resonator structure, the spatial overlap between the high-order transverse mode and the gain region (current injection region) in the active layer can be reduced. Can be suppressed. FIGS. 3A and 3B show this state. That is, FIG. 3A shows the mode distribution when there is no anti-waveguide structure, and FIG. 3B shows the mode distribution when the anti-waveguide structure is partially provided at the center of the element. It is shown. In addition, the upper stage of each figure of FIG. 3 (a), (b) shows fundamental transverse mode distribution, and the lower stage has shown primary higher order transverse mode distribution. FIGS. 3A and 3B show gain regions generated by current injection.

  The fundamental transverse mode having a large mode distribution at the center of the mesa is difficult to push the mode distribution toward the side of the mesa by the anti-waveguide structure. However, in the high-order transverse mode, the electric field strength is zero at the center of the mesa and has a large mode distribution in the peripheral region, so that the anti-waveguide structure spreads the mode distribution in the lateral direction of the mesa and in the center of the mesa. The mode distribution (electric field strength) can be easily reduced.

  Therefore, the gain for the higher-order transverse mode is reduced, and the fundamental transverse mode operation up to a high output is possible. Further, the fundamental transverse mode is not affected by the anti-waveguide structure as it is largely pushed to the periphery by the high-order transverse mode, but the peak value of the mode is suppressed as shown in FIG. The electric field intensity distribution at the center of the mode becomes gentle. As a result, the peak electric field strength in the gain region can be reduced, and the occurrence of spatial hole burning can be reduced. Also, since the high-order transverse mode is sufficiently spatially separated from the gain region by the anti-waveguide structure, it is possible to provide a larger current confinement diameter than in the prior art. Therefore, the element resistance is reduced, and a higher output operation is possible.

(4th form)
According to a fourth aspect of the present invention, there is provided an active layer, a current confinement structure that defines a current injection region into the active layer, and a pair of distributed Bragg reflectors that are opposed to each other with the active layer interposed therebetween. In the surface emitting laser element formed by the high resistance region by ion implantation, the surface emitting laser element includes an AlGaAs mixed crystal layer, and a part of the AlGaAs mixed crystal layer is defined by the current confinement structure. The region of the AlGaAs mixed crystal layer that has a spatial overlap in the laser resonance direction with the current injection region and that has a spatial overlap in the laser resonance direction and the current injection region defined by the current confinement structure is selected for molecules containing oxygen. In a peripheral region where oxygen-implanted molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted by a typical ion implantation and a heat treatment after the ion implantation. It is characterized in that forming the basis low refractive index region.

  Even in the configuration of the fourth embodiment, the AlGaAs mixed crystal in the region where the ion implantation of molecules containing oxygen has been performed is oxidized by the heat treatment, and the refractive index becomes lower than that in the peripheral region. A waveguide structure is formed. In the case where the anti-waveguide structure is formed by ion implantation of molecules containing oxygen and selective oxidation by heat treatment instead of the conventional selective oxidation in the heating atmosphere containing water vapor as in the fourth embodiment, the element structure An anti-waveguide structure can be formed at any location inside. Further, unlike the prior art, it is not necessary to expose the surface of the AlGaAs layer to the heated water vapor atmosphere for oxidation, and therefore, no oxide layer is formed on the element surface, so that regrowth is possible. Therefore, the degree of freedom in element design increases, and an element structure excellent in suppressing higher-order transverse modes can be realized.

  Further, since the ion-implanted confined surface emitting laser element does not have a built-in waveguide structure, the anti-waveguide structure can be used easily and effectively as shown in FIG. Can be spread in the lateral direction of the mesa to reduce the distribution of higher-order transverse modes (electric field strength) in the center of the mesa. As a result, the spatial overlap between the high-order transverse mode and the gain region (current injection region) in the active layer can be reduced, and oscillation of the high-order transverse mode can be suppressed. Since the ion-implanted confined surface emitting laser element does not have a built-in waveguide structure, the transverse mode is unstable and easily oscillates against changes in driving conditions. When the structure is provided, the high-order transverse mode can be stably suppressed.

  In the basic transverse mode, the peak value of the mode is suppressed as shown in FIG. 3B, and the electric field intensity distribution at the center of the mode becomes gentle. As a result, the peak electric field intensity in the gain region can be reduced. The occurrence of mechanical hole burning can be reduced.

(5th form)
According to a fifth aspect of the present invention, in the surface emitting laser element according to any one of the first to fourth aspects, the ion implantation of molecules containing oxygen in the same plane perpendicular to the laser resonance direction is not performed. On the other hand, a GaAs layer or a GaInP mixed crystal layer is provided in contact with the AlGaAs mixed crystal layer forming a region having a relatively low refractive index in the laser resonance direction.

  The GaInP and GaAs semiconductor layers are hardly oxidized even when oxygen ions are implanted. Accordingly, when the profile of oxygen ion implantation in the AlGaAs layer is not steep, etc., the AlGaAs layer is in contact with the AlGaAs layer to be selectively oxidized as in the fifth embodiment, corresponding to the spread width of the implantation profile. By adopting a configuration in which a GaInP or GaAs layer or a semiconductor structure made of these layers is provided, it is possible to prevent an oxide layer from being generated in a region other than a desired region, and the resonance conditions can be easily adjusted.

(Sixth form)
According to a sixth aspect of the present invention, in the surface-emitting laser element according to any one of the first to fifth aspects, a peripheral region where oxygen ions are not implanted in the same plane perpendicular to the laser resonance direction. On the other hand, the AlGaAs mixed crystal layer that forms the region having a relatively low refractive index is provided at a position corresponding to the antinode of the standing wave of the oscillation light in the resonator structure, and other elements constituting the element. It is characterized by relatively high doping compared to the AlGaAs mixed crystal layer.

By adopting the configuration of the sixth embodiment, the region where the ion implantation including oxygen molecules is performed and the heat treatment is performed forms AlO _x by oxidation, and becomes transparent to the fundamental transverse mode light. Therefore, there is no loss for the basic transverse mode. In addition, the region where oxygen ion-implanted ions are not implanted absorbs high-order transverse mode light having a large mode amplitude in the region due to the action of high-concentration doping. Suppress it. Also, especially at the antinodes of standing waves in the resonator, the mode distribution (electric field strength) is large, so higher absorption loss occurs for higher-order transverse mode light, effectively suppressing higher-order transverse modes. can do.

(7th form)
According to a seventh aspect of the present invention, in the surface emitting laser element according to any one of the first to sixth aspects, a plurality of the regions having a relatively low refractive index are provided.

  As in the configuration of the seventh embodiment, by providing a plurality of anti-waveguide structures composed of regions having a relatively low refractive index with respect to the peripheral region, it is possible to easily adjust the action of the anti-waveguide. The degree of freedom can be increased. Moreover, since a large anti-waveguide action can be obtained by using a plurality of anti-waveguide structures, higher-order transverse modes can be more effectively suppressed.

(8th form)
According to an eighth aspect of the present invention, in the surface emitting laser element according to any one of the first to seventh aspects, the region having a relatively low refractive index is an n-type distributed Bragg reflector of a pair of distributed Bragg reflectors. It is characterized by being provided in the reflector.

  In the configuration of the eighth embodiment, an anti-waveguide structure including a region having a relatively low refractive index with respect to the peripheral region is provided in the n-type distributed Bragg reflector, thereby effectively increasing the device resistance. Higher transverse modes can be suppressed.

(9th form)
According to a ninth aspect of the present invention, in the surface-emitting laser element according to any one of the first to eighth aspects, a relative refractive index provided with a spatial overlap in the laser resonance direction with the laser resonance region. A high refractive index region having a high refractive index with respect to the relatively low refractive index region is provided in the periphery of the low refractive index region, and is further provided in the periphery of the high refractive index region with respect to the high refractive index region. A clad region having a refractive index is provided.

  As in the prior art, an anti-waveguide structure surface emitting laser element having a low refractive index region in a region corresponding to the laser oscillation region has a mode perpendicular to the laser oscillation direction due to the nature of the waveguide structure. It has the property of easily causing (diffraction) loss due to leakage, which causes problems such as an increase in threshold current and a reduction in output.

  As a method for improving this, for example, a document “Applied Physics Letters vol. 76, No. 13, 2000, pp. 1659” shows a structure of a surface emitting laser element called S-ARROW. In this prior art, as a means for forming regions having different effective refractive indexes in the direction parallel to the substrate surface, a method of adjusting the film thickness by etching is used, and the periphery of the low refractive index region centering on the laser oscillation region is used. Is provided to provide a high refractive index region, and further to provide a low refractive index region outside the high refractive index region.

  As described above, when the high refractive index region and the low refractive index region are sequentially provided around the low refractive index region centered on the laser oscillation region, the low refractive index region centered on the laser oscillation region and the periphery thereof. The anti-waveguide structure is formed by the high refractive index region provided in the. The low-refractive index region provided around the high-refractive index region operates in the same way as the cladding layer and has a transverse mode confinement function, thus reducing leakage loss due to diffraction in a direction parallel to the substrate surface. can do.

  In addition, since light is easily confined in the high refractive index region, high-order transverse modes are particularly likely to concentrate in the high refractive index region provided between the cladding layer and the low refractive index region centered on the laser oscillation region. In addition, the coupling between the gain region and the higher order mode can be reduced. Thereby, the oscillation of the high-order transverse mode can be effectively suppressed.

  On the other hand, as a method for forming the anti-waveguide structure according to the first to eighth embodiments of the present invention, a low refraction made of an oxide of Al having a spatial overlap in the laser resonance region. When the structure of the ninth embodiment is used for the surface emitting laser element using the refractive index region, the refractive index of the Al oxide is as small as about half that of the semiconductor material. A difference in refractive index can be provided, and a large anti-waveguide effect can be easily obtained. Therefore, since the coupling between the high-order transverse mode and the gain region can be further reduced, the oscillation of the high-order transverse mode can be further effectively suppressed.

  Similarly, when the cladding region is formed of a low refractive region including an Al oxide, a large transverse mode confinement effect can be obtained, so that an operation capable of greatly reducing loss due to mode leakage can be obtained. In addition, as a method of providing an anti-waveguide structure, etching, etc., and re-growth are required when oxygen-containing molecules, ion implantation and selective oxidation by heat treatment are used as in the first to sixth embodiments. Since an element can be manufactured without using it, the element can be manufactured by a simple process.

  In particular, a hydrogen ion implanted surface emitting laser element can obtain a greater effect as described below. That is, since the hydrogen ion-implanted surface emitting laser element does not have a transverse mode confinement structure, there is a problem that loss due to mode leakage tends to increase when an anti-waveguide structure is used. On the other hand, the loss due to mode leakage can be greatly reduced by providing a low refractive index clad made of Al oxide outside the laser oscillation region as in the case of the surface emitting laser element of the ninth embodiment. Is possible.

  In addition, the cladding region for confining the transverse mode may have a periodic structure in which a low refractive index region and a high refractive index region are alternately and repeatedly provided. In such a periodic structure with a refractive index, the distribution Bragg provided in the laser resonance direction is selected by selecting the width of each region as an odd multiple of ¼ of the wavelength in the plane perpendicular to the laser oscillation direction of the fundamental transverse mode light. It is possible to form a light confinement structure (resonator) similar to that of a reflector. By appropriately selecting a repetition period and adjusting the width of the reflection band, a high light confinement effect for only fundamental transverse mode light Can be obtained.

  As described above, in the ninth embodiment, mode leakage in a direction perpendicular to the laser resonance direction is reduced, and a higher higher-order transverse mode suppression effect can be obtained. Single fundamental transverse mode oscillation is obtained.

(10th form)
A tenth aspect of the present invention is characterized in that, in the surface emitting laser element of the ninth aspect, anisotropy is provided in the width of the high refractive index region surrounded by the cladding region.

  In the tenth embodiment, by providing anisotropy to the width of the region surrounded by the cladding region in the direction perpendicular to the laser resonance direction, the polarization direction of the laser oscillation light is controlled to a specific direction, and further increased. Single fundamental transverse mode oscillation up to output is possible.

  As described in the ninth embodiment, when the high refractive index region and the low refractive index region are provided surrounding the low refractive index region around the laser oscillation region, the low refractive index provided outside the high refractive index region is provided. The rate region operates as a cladding layer and the transverse mode is confined, so that loss due to mode leakage can be reduced. In addition, since the high-order transverse mode is concentrated in the high-refractive index region provided between the cladding layer and the low-refractive index region centered on the laser oscillation region, the coupling between the gain region and the high-order transverse mode is reduced. It is possible to suppress the oscillation of the higher-order transverse mode.

  Furthermore, as in the tenth embodiment, when the width of the region sandwiched between the low-refractive index cladding regions is an anisotropic shape such as a rectangle (or an elliptical shape), the lateral confinement is anisotropic. And the transverse mode distribution can be changed between directions in which anisotropy is provided. At this time, the width of the region sandwiched by the low refractive index cladding, the effective refractive index of the cladding region, the high refractive index region, and the low refractive index core are appropriately adjusted, and the fundamental transverse mode distribution in a specific direction is determined as the gain region. Therefore, only the fundamental transverse mode having polarization in a specific direction can be selectively oscillated.

  Since the high-order transverse mode has a small electric field amplitude in the laser oscillation region, it is easily affected by the anti-waveguide structure. Therefore, by using the anti-waveguide structure, the coupling with the gain region is originally small, and the oscillation is It can be suppressed sufficiently.

  As described above, in the tenth embodiment, it is possible to provide an element in which polarization is controlled and single fundamental transverse mode operation is possible up to a high output.

(Eleventh form)
According to an eleventh aspect of the present invention, in the surface emitting laser element according to the ninth aspect, the cladding region is provided only in a pair of directions perpendicular to a laser resonance direction facing each other with the laser resonance region interposed therebetween. It is a feature.

  In the surface-emitting laser element according to the eleventh aspect, the low refractive index region made of Al oxide provided outside the region centered on the laser oscillation region is provided only in a pair of directions facing each other with the laser resonance region interposed therebetween. With this configuration, the polarization direction is controlled to a specific direction, and single fundamental transverse mode operation can be obtained up to high output.

  As described above, the anti-waveguide structure tends to easily cause a loss due to lateral mode leakage. In order to reduce mode leakage loss, it is effective to provide a low refractive index cladding as in the surface emitting laser element of the ninth embodiment. Accordingly, by providing the low refractive index cladding layer only in a pair of directions sandwiching the laser oscillation region as in the case of the surface emitting laser element of the eleventh embodiment, the mode is provided in the direction in which the low refractive index cladding region is provided. The fundamental transverse mode having an electric field component (polarized light) in this direction can be selectively oscillated.

  In particular, since the hydrogen ion implantation surface emitting laser element does not have a waveguide structure, mode leakage is particularly likely to occur, and the oscillation gain in the direction in which the low refractive index cladding region is provided and in the direction in which the low refractive index cladding is not provided. The difference is big. Therefore, it is possible to obtain a high polarization ratio.

  As described above, according to the eleventh embodiment, it is possible to provide an element in which the polarization direction is controlled to a specific direction and which can perform a high output operation in the single basic transverse mode.

(Twelfth embodiment)
According to a twelfth aspect of the present invention, in the surface emitting laser element according to any one of the first to eleventh aspects, the region having a relatively low refractive index provided so as to have a spatial overlap with the laser resonance region, It is characterized by having an anisotropic shape.

  Like the surface emitting laser element of the twelfth embodiment, the shape of the low refractive index core region made of an oxide of Al provided with a spatial overlap in the laser oscillation region is, for example, rectangular or elliptical When the anisotropic shape is used, anisotropy occurs in the lateral confinement, as in the tenth embodiment, and the transverse mode distribution can be changed between the directions in which the anisotropy is provided. At this time, by appropriately adjusting the width of the low refractive index core region and the effective refractive index and setting the basic transverse mode distribution in a specific direction so as to obtain high coupling with the gain region, Only the fundamental transverse mode having polarization can be selectively oscillated.

  Since the high-order transverse mode has a small electric field amplitude in the laser oscillation region, it is easily affected by the anti-waveguide structure. Therefore, by using the anti-waveguide structure, the coupling with the gain region is originally small, and the oscillation is It can be suppressed sufficiently.

  As described above, according to the twelfth embodiment, it is possible to provide an element in which the polarization direction is controlled to a specific direction and capable of high output operation in the single basic transverse mode.

(13th form)
According to a thirteenth aspect of the present invention, in the surface emitting laser element of any one of the first to twelfth aspects, the active layer is composed of a III-V group element, and the group III elements constituting the active layer are Ga, It includes any or all of In, and also includes any or all of As, N, Sb, and P as a group V element.

  By adopting the configuration of the thirteenth embodiment, an element optimal for an optical communication light source having particularly excellent temperature characteristics can be obtained.

(14th form)
A fourteenth aspect of the present invention is a surface emitting laser array characterized in that the surface emitting laser elements of any one of the first to thirteenth aspects are arranged in an array.

  The surface-emitting laser array according to the fourteenth embodiment operates as a surface-emitting laser array that can oscillate to a high output in a single fundamental transverse mode.

(15th form)
According to a fifteenth aspect of the present invention, there is provided an optical interface characterized in that the surface-emitting laser element according to any one of the first to thirteenth aspects or the surface-emitting laser array according to the fourteenth aspect is used as a light source. It is a connection system.

  The surface-emitting laser elements of the first to thirteenth forms and the surface-emitting laser array of the fourteenth form are capable of oscillating to a high output in a single fundamental transverse mode, have high coupling with an optical fiber, and operate the element. Since the transverse mode is stable even when the state changes, the optical interconnection system in which the transverse mode is used as a light source is highly reliable.

(16th form)
A sixteenth aspect of the present invention is a light characterized in that the surface-emitting laser element according to any one of the first to thirteenth aspects or the surface-emitting laser array according to the fourteenth aspect is used as a communication light source. It is a communication system.

  The surface-emitting laser elements of the first to thirteenth forms and the surface-emitting laser array of the fourteenth form are capable of oscillating to a high output in a single fundamental transverse mode, have high coupling with an optical fiber, and operate the element. Since the transverse mode is stable even with respect to a change in state, an optical communication system in which this is used as a communication light source is highly reliable. In addition, since the basic transverse mode output is high, the optical communication system is capable of long-distance communication.

(17th form)
According to a seventeenth aspect of the present invention, the surface emitting laser element according to any one of the first to thirteenth aspects or the surface emitting laser array according to the fourteenth aspect is used as a light source for writing. An electrophotographic system.

  The surface-emitting laser elements of the first to thirteenth forms and the surface-emitting laser array of the fourteenth form can oscillate to a high output in a single fundamental transverse mode. In addition, since the outgoing beam is circular and has high positional accuracy between the arrays, multiple beams can be easily collected with the same lens with good reproducibility, so the optical system is simple and low cost. A simple electrophotographic system. In addition, since a high output can be obtained in the basic transverse mode, when an array is used, particularly high-speed writing is possible, and a high-speed electrophotographic system can be configured.

(18th form)
According to an eighteenth aspect of the present invention, the surface emitting laser element according to any one of the first to thirteenth aspects or the surface emitting laser array according to the fourteenth aspect is used as a read / write light source. This is an optical disk system.

  The surface-emitting laser elements of the first to thirteenth forms and the surface-emitting laser array of the fourteenth form are reliable in that they can oscillate to a high output in a single fundamental transverse mode and the output beam is circular. A highly reliable optical disk system can be configured. In particular, when an array is used, high-density reading / writing is possible, and a high-speed optical disk system can be configured.

FIG. 1 is a view showing a surface emitting laser element according to Example 1. FIG. The surface emitting laser element of FIG. 1 is a 0.85 μm band surface emitting laser element having a GaAs / Al _0.15 Ga _0.85 As multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process.

The surface emitting laser element of FIG. 1 is grown by metal organic vapor phase epitaxy (MOCVD), and trimethylaluminum (TMA), trimethylgallium (TMG), and trimethylindium (TMI) are used as group III materials. In addition, arsine (AsH ₃ ) gas is used as the group V raw material. Further, CBr ₄ is used for the p-type dopant, and H ₂ Se is used for the n-type dopant.

Specifically, the element of FIG. 1 includes an n-GaAs buffer layer 102 and an n-Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As pair on an n-GaAs substrate 101. 36 cycles was period _{n-Al 0.9 Ga 0.1 as /} Al 0.15 Ga 0.85 as lower semiconductor DBR 103, a non-doped _Al 0.15 _{Ga 0.85} as the cavity spacer 104, GaAs / Al _0.15 Ga _0.85 As multiple quantum well active layer 105, non-doped Al _0.15 Ga _0.815 As resonator spacer 106, 20 periods of p-Al _0.9 Ga _0.1 As / Al _{0 .15} Ga _0.85 As upper semiconductor distributed Bragg reflector 107 is sequentially crystal-grown. In the Al _0.15 Ga _0.85 As layer, which is the outermost surface layer of the upper distributed Bragg reflector 107, a contact layer (not shown) with a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided. Provided. Further, a p-AlAs selectively oxidized layer 108 is provided in the p-Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As upper semiconductor distributed Bragg reflector 107 for current confinement. Yes. Here, the p-AlAs selectively oxidized layer 108 is oxidized in the heated atmosphere containing water vapor by performing selective oxidation from the etching end face (region shown in black; also in the following examples). And a region where oxidation is not performed.

In the surface emitting laser element of FIG. 1, after crystal growth, a square resist pattern having a side of 30 μm is formed by a known photolithography technique, and p-Al _0.9 Ga _0.1 As is formed using a known dry etching technique. / Al _0.15 Ga _0.85 As From the surface of the upper semiconductor distributed Bragg reflector 107 to the n-Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As lower distributed semiconductor Bragg reflector 103 The square mesas are formed by performing the etching removal of the respective layers up to.

Next, a square resist opening pattern is formed in alignment with the center of the mesa, and oxygen molecule ions are implanted into the center of the mesa. In the figure, the oxygen ion implantation region 113 is shown. Next, after removing the resist, the p-AlAs selectively oxidized layer 108 is selectively oxidized in a direction parallel to the substrate from the etching end face toward the center of the mesa in a heated atmosphere containing water vapor to selectively oxidize the resist. A current confinement structure is formed. In addition, by the heat treatment in the selective oxidation step in the heating atmosphere containing water vapor, in the oxygen ion implantation region 113, the oxidation of the Al _0.9 Ga _0.1 As mixed crystal proceeds at the same time. A selective oxidation region by oxygen ion implantation having a relatively low refractive index as compared with the region is formed. Here, the length of one side of the oxygen ion implantation region is 15 μm, and the length of one side of the current confinement region is 10 μm.

Next, a SiO ₂ layer 109 is formed on the entire surface of the wafer by vapor phase chemical deposition (CVD), and then aligned with the center of the mesa and spin-coated with an insulating resin 110 to insulate the mesa. Resin is removed. Next, the SiO ₂ layer 109 is removed from the insulating resin removal portion, a 10 μm square resist pattern is formed in a region to be a light emitting portion on the mesa, and p-type electrode material is deposited. Next, the electrode material of the emission part is removed by lift-off, and the p-side electrode 111 is formed. Next, after polishing the back surface of the n-GaAs substrate 101, an n-side electrode 112 is provided on the back surface of the substrate 101 by vapor deposition, and ohmic conduction between the electrodes 111 and 112 is achieved by annealing.

FIG. 2 is a diagram showing in detail a part of region 113 where oxygen ion implantation is performed in FIG. The Al _0.9 Ga _0.1 As mixed crystal located in the region where oxygen ion implantation has been performed reacts with Al atoms and is oxidized by heat treatment after oxygen ion implantation, and the surrounding Al _0.9 Ga _{0. A} region with a relatively low refractive index (region shown in black) is formed relative to the ₁ As mixed crystal, and an anti-waveguide structure is formed in the resonator. The AlGaAs mixed crystal has a higher Al composition and is more likely to be oxidized, and the GaAs layer of the device is hardly oxidized. In addition, since the oxide structure for forming the anti-waveguide structure at the center of the mesa only needs to have a relatively low refractive index as compared with the peripheral region, the AlGaAs mixed crystal must be completely oxidized. There is no. Therefore, in other words, the amount of oxygen ions implanted can be adjusted so as to obtain a desired refractive index change for the design.

Here, the thickness of the AlGaAs mixed crystal subjected to oxygen ion implantation is selected in advance so that the phase condition of multiple reflection of the distributed Bragg reflector is satisfied with the refractive index and film thickness after heat treatment. . That is, the region where the refractive index is relatively lowered by ion implantation and heat treatment is formed as a low refractive index layer of the distributed Bragg reflector. Therefore, the p-Al _0.9 Ga _0.1 As that has been ion-implanted is different in thickness from the p-Al _0.9 Ga _0.1 As layer positioned above and below the p-Al _0.9 Ga _0.1 As layer. In consideration of the above, it is formed thicker than p-Al _0.9 Ga _0.1 As in other regions. The film thickness of the distributed Bragg reflector including the oxygen ion implantation region is set to a layer thickness at which the phase change of the oscillation light in each layer is π / 2 so that the multiple reflection phase condition of the Bragg reflector is satisfied. .

  In this way, by setting the thickness of the AlGaAs mixed crystal in the ion implantation region so that the Bragg reflection resonance condition is satisfied with respect to the refractive index after oxidation, the mesa center (the site where the ion implantation is performed) Then, a high reflectance is obtained with respect to the resonance wavelength, and conversely, from the center to the side surface of the mesa where ion implantation has not been performed, the reflectance can be lowered by the collapse of the phase condition. Therefore, a higher-order mode having a large mode amplitude in a region where the reflectivity is reduced can increase the reflector loss and can also suppress the oscillation.

  The surface emitting laser element of FIG. 1 has a high-order transverse mode distribution as shown in FIG. 3B due to the anti-waveguide structure composed of a low refractive region provided by oxygen ion implantation into AlGaAs mixed crystal and heat treatment. In this way, the overlap with the gain region determined by the current injection diameter schematically shown in the figure is reduced, and the reflectivity of the Bragg reflector is lowered at the periphery of the mesa. Oscillation in the transverse mode was suppressed, and a single fundamental transverse mode oscillation could be obtained up to a higher output than conventional devices.

  4 and 5 are diagrams for explaining the surface emitting laser element according to the second embodiment. Referring to FIG. 4, in Example 2, in the surface emitting laser element of FIG. 1, a part of the p-type distributed Bragg reflector 107 is crystal-grown by the same method as that of the element of Example 1. In Example 2, after the crystal growth to the middle of the p-type distributed Bragg reflector 107 was performed, the crystal growth of the device was temporarily interrupted, and oxygen was previously applied to the region that becomes the central part of the mesa as in Example 1. After ion implantation of the contained molecules, heat treatment is performed to recover crystal defects caused by the implantation, and the remaining element portion is provided by regrowth. At this time, the region 113 into which oxygen is ion-implanted is selectively oxidized by the heat treatment performed to recover the crystal defects and the heating during the crystal growth of the remaining element portion, and has a low refractive index relative to the peripheral region. An anti-waveguide structure is formed.

  By using such a manufacturing procedure, the depth for performing oxygen ion implantation can be reduced, so that a sharp implantation profile can be obtained with very good controllability. Therefore, it is possible to accurately limit the region in which the refractive index changes by the heat treatment in the growth direction, and it is very easy to adjust the phase condition of multiple reflection in the distributed Bragg reflector.

Further, as shown in FIG. 5, Ga _0.5 In _0.5 P / Al _0.15 is placed before and after the distributed Bragg reflector made of Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As. By providing a distributed Bragg reflector made of Ga _0.85 As, it is possible to adjust the phase condition more precisely. In FIG. 5, one pair of Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As distributed Bragg reflector is in contact with Ga _0.5 In _0.5 P / Al _0.15 Ga _0. An example in which a distributed Bragg reflector made of ₈₅ As is provided is shown. In other words, Ga _0.5 In _0.5 P can be crystal-grown by lattice matching with a GaAs substrate, and further contains no Al as a constituent element, so even if oxygen ion implantation is performed, Little oxidation proceeds. Therefore, even when there is a distribution in the implanted ion width, it is possible to oxidize only the AlGaAs layer in a specific region. Further, by oxidizing only AlGaAs at a desired position in this way, it becomes easy to precisely adjust the reflection wavelength of the distributed Bragg reflector in the center of the mesa (reflection wavelength with respect to the fundamental transverse mode) with good controllability. .

As described above, in Example 2, when the growth of the upper distributed Bragg reflector is interrupted and oxygen ions are implanted first as shown in FIG. 4, a steep oxygen atom implantation profile is obtained. Furthermore, by providing a Ga _0.5 In _0.5 P / Al _0.15 Ga _0.85 As distributed Bragg reflector as shown in FIG. 5, selective oxidation is performed more precisely by ion implantation. It is possible to control the area where In addition, since the ion implantation profile is steep, the number of layers of the Ga _0.5 In _0.5 P / Al _0.15 Ga _0.85 As distributed Bragg reflector provided to prevent oxidation can be reduced. The impact on the rate can be kept to a minimum.

  The surface-emitting laser device of Example 2 fabricated in this way has an anti-waveguide structure provided by oxygen ion implantation into an AlGaAs mixed crystal and selective oxidation by heat treatment in the same manner as the device of Example 1. As shown in (b), the distribution of the high-order transverse mode is pushed to the periphery of the mesa, and the overlap with the gain region determined by the current injection diameter schematically shown in FIG. This reduces the reflectivity of the Bragg reflector, suppresses higher-order transverse mode oscillation, and can achieve single fundamental transverse mode oscillation up to a higher output than conventional devices. Further, since the reflection conditions of the distributed Bragg reflector can be adjusted with good controllability, an element having excellent characteristics such as oscillation threshold characteristics can be obtained.

  FIG. 6 is a view for explaining the surface emitting laser element of Example 3. Referring to FIG. 6, in Example 3, the region around the anti-waveguide structure 113 in the surface emitting laser element of FIG. 1 has a different configuration.

That is, in FIG. 6, Al _0.9 Ga _0.1 As mixed crystal provided for forming a low refractive index region in selective oxidation by ion implantation of a molecule containing oxygen and heat treatment is used as Al Al in other regions. Crystal growth is performed such that the doping density is higher than that of the _0.9 Ga _0.1 As mixed crystal. Other device manufacturing procedures and methods are the same as those of the device of Example 1.

  A highly doped semiconductor has significant light absorption due to free carrier absorption or the like. In particular, a p-type semiconductor has a property that absorption is increased particularly for light having a long wavelength because there is absorption between valence bands in addition to this.

Therefore, if the Al _0.9 Ga _0.1 As layer forming the low refractive index region is doped at a high concentration during crystal growth by ion implantation and oxidation by heat treatment as in Example 3, p − In addition to reducing the series resistance of the DBR, the absorption loss due to free carrier absorption or valence band absorption in the anti-waveguide structure is increased. However, at the site where oxygen ion implantation has been performed, an insulator made of AlO _x is formed and changes transparently with respect to the oscillation wavelength, so that it corresponds to the fundamental transverse mode having a large mode amplitude at the central portion (ion implantation region) of the mesa. Absorption loss is eliminated, and absorption occurs only for higher-order transverse modes having a large mode amplitude from the center to the side of the mesa. Therefore, it is possible to suppress the oscillation of the high-order transverse mode by increasing the absorption loss.

Further, by adopting the configuration of FIG. 7, it is possible to further increase the absorption effect of the higher-order transverse mode. Here, FIG. 7 shows another configuration example of the oxygen ion implantation region 113 of the surface emitting laser element in the first embodiment. As in FIG. 6, Al with high conductivity p-type doping is applied. _{A 0.9} Ga _0.1 As layer is provided. The difference from FIG. 6 is that an Al _0.9 Ga _0.1 As layer having a thickness of 3 / 4λ is provided. The standing wave of the oscillation light in the distributed Bragg reflector has a distribution in which the nodes and antinodes of the electric field are repeated for each λ / 4 thickness (in terms of phase, every π / 2). In the nλ resonator, the interface from Al _0.9 Ga _0.1 As to Al _0.15 Ga _0.85 As viewed from the resonator side becomes a node of the electric field, and conversely, Al _0.15 Ga _0.85 As. The interface from Al _0.9 Ga _0.1 As to Al _0.9 Ga _0.1 As is the antinode of the electric field. Therefore, as shown in FIG. 7, when an Al _0.9 Ga _0.1 As layer having a thickness of 3 / 4λ is provided, the Al _0.9 Ga _0.1 As layer includes an antinode of a standing wave. Become. In FIG. 7, the location indicated by the arrow corresponds to the antinode position of the standing wave. At the position corresponding to the antinode of this standing wave, the amount of absorption by the Al _0.9 Ga _0.1 As layer doped at a high concentration increases corresponding to the increase in the electric field strength of light. Therefore, as described above, the absorption loss for the higher-order transverse mode can be further increased. Therefore, it is possible to obtain a larger suppression effect of the high-order transverse mode.

  As in Example 3, an AlGaAs layer that forms an anti-waveguide structure composed of a low refractive index region by ion implantation of oxygen-containing molecules and selective oxidation by heat treatment is higher than the AlGaAs layer in other regions during crystal growth. When the concentration is doped, an absorption region for high-order transverse mode light can be formed around the low refractive index region. As described above, the element of Example 3 was able to obtain single fundamental transverse mode oscillation up to a higher output.

  FIG. 8 is a diagram showing a surface emitting laser element according to Example 4. The surface emitting laser element of FIG. 8 is a 1.3 μm band surface emitting laser element having a GaInNAs / GaAs multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process.

The surface emitting laser element of FIG. 8 is crystal-grown by metal organic vapor phase epitaxy (MOCVD method), similar to the element of Example 1, and trimethylaluminum (TMA), trimethylgallium ( TMG) and trimethylindium (TMI) are used, and arsine (AsH ₃ ) gas is used as the group V raw material. Further, CBr ₄ is used for the p-type dopant, and H ₂ Se is used for the n-type dopant. Further, dimethylhydrazine (DMHy) is used as a nitrogen raw material for the active layer.

Specifically, the element shown in FIG. 8 includes an n-GaAs substrate 201 and an n-GaAs buffer layer 202, an n-Al _0.9 Ga _0.1 As / GaAs pair having 36 cycles of n −. Al _0.9 Ga _0.1 As / GaAs lower semiconductor distributed Bragg reflector 203, non-doped GaAs resonator spacer 204, GaInNAs / GaAs multiple quantum well active layer 205, non-doped GaAs resonator spacer 206, 20-period p-Al _{0 .9} Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 207 is successively grown. In addition, in the GaAs layer which is the outermost surface layer of the upper distributed Bragg reflector 207, a contact layer (not shown) having a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided. A p-AlAs selectively oxidized layer 208 is provided in the p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 207.

  In the device of FIG. 8, the growth was interrupted in the middle of crystal growth of the n-conductivity distributed Bragg reflector, and oxygen ions were implanted into the center of the mesa in the same manner as in the device of Example 2, Annealing is performed to recover crystal defects, and the remaining elements are grown again. At this time, the region 213 into which oxygen is ion-implanted is selectively oxidized to have a low refractive index with respect to the peripheral region by heat treatment performed to recover crystal defects and heating during crystal growth of the remaining element portion. An anti-waveguide structure is formed.

  Thereafter, mesa formation and p-AlAs selective oxidation layer 208 are selectively oxidized in a heating atmosphere containing water vapor by means and methods similar to those of the device of Example 1, and buried and planarized with resin and electrodes are formed. 8 is a surface emitting laser element.

  Here, the surface emitting laser element of Example 4 is that the anti-waveguide structure 213 by the low refractive index layer formed by ion implantation and heat treatment is provided in the n-type distributed Bragg reflector. This is significantly different from the first to third embodiments. As for the layer structure around the anti-waveguide structure, any structure described in the first to third embodiments can be used by setting the conductivity type to n-type. By providing the anti-waveguide structure in the n-conductivity distributed Bragg reflector like the element of the fourth embodiment, it is possible to efficiently suppress the higher-order transverse mode as in the first to third embodiments. In addition, the resistance of the element can be greatly reduced.

  If an anti-waveguide structure is provided in the p-conductivity type semiconductor so as to spatially overlap with the current injection region, this region has a high resistance. There is a problem that the current path becomes long and narrow because the injection is performed after constricting again to the center of the mesa. Since the p-conductivity type semiconductor has a carrier (hole) mobility that is about an order of magnitude smaller than that of the n-conductivity type semiconductor, there arises a problem that the resistance of the element is easily increased.

  On the other hand, when the anti-waveguide structure is provided in the n-conduction type distributed Bragg reflector as in the fourth embodiment, there is no current confinement structure between the anti-waveguide structure and the active layer, and the electron Because of the high mobility, even if there is an insulating (or high resistance) region in the center of the mesa, the increase in resistance is very small, and the resistance of the element can be kept at the same level as that of the conventional element. Is possible. The anti-waveguide structure has almost the same effect on the transverse mode regardless of whether it is provided in the p-conductivity type distributed Bragg reflector or the n-conductivity type distributed Bragg reflector. The same effect as 2 can be obtained.

  In the element of Example 4, as in Examples 1 to 3, a single basic transverse mode operation was possible up to a high output, and the element resistance was sufficiently low. Further, since the resistance of the element is reduced, it is possible to obtain a higher output operation.

  FIG. 9 is a diagram showing a surface emitting laser element according to Example 5. The surface emitting laser element of FIG. 9 is a 1.3 μm band surface emitting laser element having a GaInNAs / GaAs multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process.

  The surface emitting laser element shown in FIG. 9 is grown by the same method and means as in the fourth embodiment.

Specifically, the device of FIG. 9 includes an n-GaAs substrate 301 on an n-GaAs buffer layer 302 and an n-Al _0.9 Ga _0.1 As / GaAs pair having 36 cycles of n −. Al _0.9 Ga _0.1 As / GaAs lower semiconductor distributed Bragg reflector 303, non-doped GaAs resonator spacer 304, GaInNAs / GaAs multiple quantum well active layer 305, non-doped GaAs resonator spacer 306, 20 periods of p-Al _{0 .9} Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 307 is sequentially crystal-grown. In addition, in the GaAs layer that is the outermost surface layer of the upper distributed Bragg reflector 307, a contact layer (not shown) having a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided.

In the surface emitting laser element of FIG. 9, after crystal growth, a square resist opening pattern having a side of 3 μm is formed by a known photolithography technique, and p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflection is performed. Oxygen ion implantation is performed from the surface of the vessel 307. Next, the oxygen ion implanted portion is selectively oxidized by heat treatment to provide an anti-waveguide structure including the low refractive index region 313. FIG. 9 also shows the effective refractive index in the direction parallel to the substrate surface, and the effective refractive index is relatively small in the portion where the low refractive index region is provided. Thereafter, alignment with the oxygen ion implanted portion is performed again to form a 10 μm resist pattern, hydrogen ions are implanted so that the implantation peak is deeper than the oxygen ion implanted portion, and the resistance of the hydrogen ion implanted portion is increased. Yes. Here, the high resistance region can also be formed by implanting oxygen ions instead of hydrogen ions.

  Next, a p-type electrode 311 is formed on the surface of the device, and after polishing the back surface of the substrate 301, an n-type electrode 312 is formed on the back surface of the substrate 301, and ohmic conduction is achieved by annealing. It is said.

  Here, in the surface emitting laser element using the current confinement structure by hydrogen ion implantation as shown in FIG. 9, there is almost no change in the refractive index of the hydrogen ion implanted portion, and there is no built-in optical confinement structure (waveguide structure). The action of the anti-waveguide structure on the mode distribution is larger than that of the oxidized confined surface emitting laser element. Therefore, the high-order transverse mode can be pushed out to the outside of the gain region very efficiently, and the effect of suppressing the high-order transverse mode can be remarkably obtained. In the element of Example 5, the oxygen ion implantation region is positioned close to the element surface away from the active layer so that the influence on the fundamental transverse mode is not too great, and the width of the oxygen ion implantation region is about 3 μm. It is narrow.

  In order to prevent the resistance of the p-conductivity-type Bragg reflector 307 from becoming high, the hydrogen ion implantation voltage is increased sufficiently to increase the implantation depth so that the oxygen ion implantation region and the hydrogen ion implantation region do not overlap. is doing. In the element of Example 5, single basic transverse mode operation was possible up to very high output.

  FIG. 10 is a diagram showing an example in which the anti-waveguide structure 313 is provided in the n-type distributed Bragg reflector 303 in the same manner as in the fourth embodiment with respect to the surface emitting laser element of FIG. That is, in the example of FIG. 10, as in Example 4, the growth is temporarily interrupted during the crystal growth of the n-type distributed Bragg reflector 303, and oxygen ion implantation regions are obtained by ion implantation of molecules containing oxygen and heat treatment. After the selective oxidation of 313, crystal growth of the remaining element portion was performed. The element of FIG. 10 has a very large high-order transverse mode suppression effect similar to the element of FIG. 9 and also has an anti-waveguide structure in the n-type distributed Bragg reflector. In addition, the resistance of the element can be reduced.

  In fact, the device of Example 5 was capable of single basic transverse mode operation up to a very high output, and the device resistance was sufficiently low. Further, since the resistance of the element is reduced, it is possible to obtain a higher output operation.

  FIGS. 11A and 11B are views showing a surface emitting laser element of Example 6. FIG. In addition, FIG.11 (b) is a figure which shows the top view of the surface emitting laser element of Fig.11 (a). 11A and 11B are 1.3 μm band surface emitting laser elements having a GaInNAs / GaAs multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process.

In the surface emitting laser elements of FIGS. 11A and 11B, crystals are grown by the same method and means as in the fourth embodiment. Specifically, in the device of FIGS. 11A and 11B, an n-GaAs buffer layer 302 and an n-Al _0.9 Ga _0.1 As / GaAs pair are formed on an n-GaAs substrate 301 for one period. N-Al _0.9 Ga _0.1 As / GaAs lower semiconductor distributed Bragg reflector 303, non-doped GaAs resonator spacer 304, GaInNAs / GaAs multiple quantum well active layer 305, non-doped GaAs resonator spacer 306, A 20-period p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 307 is sequentially crystal-grown. In addition, in the GaAs layer that is the outermost surface layer of the upper distributed Bragg reflector 307, a contact layer (not shown) having a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided.

The surface emitting laser elements of FIGS. 11A and 11B have openings at portions corresponding to the low refractive index regions 1 and 2 of FIG. 11B by using a known photolithography technique after crystal growth. After the formation of the square resist pattern, oxygen ions are implanted from the surface of the p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 307. Next, the oxygen ion implanted portion is selectively oxidized by heat treatment to form a low refractive index region 1 for forming an anti-waveguide structure in the central portion of the device and a low refractive index for confining a transverse mode in the peripheral portion of the device. A refractive index region 2 (cladding region) is formed. Here, the resist pattern opening d1 in the region corresponding to the low refractive index region 1 is 5 μm, and the resist pattern opening d2 in the region corresponding to the low refractive index region 2 is 30 μm. FIG. 11A also shows the effective refractive index in the direction parallel to the substrate surface, and the effective refractive index is relatively small in the portion where the low refractive index region is provided. In this embodiment, a high refractive index region is formed on both sides of a low refractive index core located in the center of the element, and a clad made of a low refractive region is provided outside the high refractive region.

  Thereafter, alignment is again made to the oxygen ion implanted portion, a square resist pattern is formed, hydrogen ions are implanted so that the implantation peak is deeper than the oxygen ion implanted portion, and the resistance of the hydrogen ion implanted portion is increased. ing. One side d3 of the resist pattern was 8 μm. Here, the high resistance region can also be formed by implanting oxygen ions instead of hydrogen ions.

  Next, a p-type electrode 311 is formed on the element surface, and after polishing the back surface of the substrate 301, an n-type electrode 312 is formed on the back surface of the substrate 301, and ohmic conduction is performed by annealing. The surface-emitting laser element b) is used.

  Conventional surface emitting laser elements using a current confinement structure by hydrogen ion implantation have almost no change in the refractive index of the hydrogen ion implanted portion and have no built-in optical confinement structure (waveguide structure). The effect of the anti-waveguide structure is greater than that of the element. Therefore, it is possible to obtain a great effect of spreading the mode distribution to the peripheral portion of the element. However, on the other hand, there is a problem that mode leakage in the lateral direction is likely to occur and loss is likely to increase. On the other hand, in the surface emitting laser element of this example, since the transverse mode is confined by providing a clad made of a low refractive index region in the periphery of the element, it is possible to reduce the loss due to mode leakage. .

  The effective refractive index in the low refractive index regions 1 and 2 can be adjusted by the thickness and depth of the Al oxide region. Furthermore, oxygen ion implantation into the portions corresponding to the low refractive index regions 1 and 2 can be performed in two steps for each region by different acceleration voltages and ion currents. Moreover, the dimension of each part can also be made into the value other than shown in a present Example. Greater effects can be obtained by selecting the dimensions and ion implantation conditions optimally so that the coupling between the fundamental transverse mode and the gain region is large and the coupling between the higher-order transverse mode and the gain region is low. it can.

  From the above, the element of this example was capable of single basic transverse mode operation up to higher output.

  12A and 12B are views showing a surface emitting laser element of Example 7. FIG. In addition, FIG.12 (b) is a figure which shows the top view of the surface emitting laser element of Fig.12 (a). The surface emitting laser elements shown in FIGS. 12A and 12B are 0.98 μm band surface emitting laser elements having a GaInAs / GaAs multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process. The surface emitting laser elements of FIGS. 12A and 12B are grown by the same method and means as in the fourth embodiment.

Specifically, the device of FIGS. 12A and 12B has an n-GaAs buffer layer 402 and an n-Al _0.9 Ga _0.1 As / GaAs pair on an n-GaAs substrate 401 for one period. N-Al _0.9 Ga _0.1 As / GaAs lower semiconductor distributed Bragg reflector 403, non-doped GaAs resonator spacer 404, GaInAs / GaAs multiple quantum well active layer 405, non-doped GaAs resonator spacer 406, A 20-period p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 407 is sequentially grown. Further, in the GaAs layer which is the outermost surface layer of the upper distributed Bragg reflector 407, a contact layer (not shown) having a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided.

The surface-emitting laser elements shown in FIGS. 12A and 12B have a square shape having an opening in a portion corresponding to the low refractive index region 1 shown in FIG. 12B by using a known photolithography technique after crystal growth. And a rectangular resist pattern having an opening in a portion corresponding to the low refractive index region 2, and then a p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 407. Oxygen ion implantation is performed from the surface. Next, the oxygen ion implanted portion is selectively oxidized by heat treatment to form a low refractive index region 1 for forming an anti-waveguide structure in the central portion of the device and a low refractive index for confining a transverse mode in the peripheral portion of the device. A refractive index region 2 is formed. Here, the opening d1 of the resist pattern in the region corresponding to the low refractive index region 1 is set to 5 μm. In the resist pattern in the region corresponding to the low refractive index region 2 (cladding region), the opening d2 in the first direction in FIG. 12B is 40 μm, and the opening d4 in the second direction is 20 μm. FIG. 12A also shows the effective refractive index in a direction parallel to the substrate surface, and the effective refractive index is formed to be relatively small at the portion where the low refractive index region is provided. In this embodiment, a high refractive index is formed on both sides of a low refractive index core located at the center of the element, and a clad composed of a low refractive region is provided outside the high refractive region.

  Thereafter, the resist pattern is aligned again with the oxygen ion implanted portion to form a square resist pattern, hydrogen ions are implanted so that the implantation peak is deeper than the oxygen ion implanted portion, and the resistance of the hydrogen ion implanted portion is increased. A current confinement structure is formed. One side d3 of the resist pattern was 8 μm. Here, the high resistance region can also be formed by implanting oxygen ions instead of hydrogen ions.

  Next, a p-type electrode 311 is formed on the element surface, and after polishing the back surface of the substrate 301, an n-type electrode 312 is formed on the back surface of the substrate 301, and ohmic conduction is performed by annealing. The surface-emitting laser element b) is used.

  In the surface emitting laser element of the present example, the width of the region sandwiched between the laser resonance region and the first direction by the low refractive index region 2 (cladding region) is perpendicular to the laser resonance direction. The widths are different from each other. Thereby, the mode distributions in the first direction and the second direction can be made different from each other. At this time, by setting the fundamental transverse mode distribution in a specific direction so as to obtain high coupling with the gain region, it is possible to selectively oscillate only the fundamental transverse mode having polarization in the specific direction. Since the high-order transverse mode has a small electric field amplitude in the laser oscillation region, it is easily affected by the anti-waveguide structure. Therefore, by using the anti-waveguide structure, the coupling with the gain region is originally small, and the oscillation is It can be suppressed sufficiently.

  The dimensions of each part can be set to values other than those shown in the present embodiment, and the effective refractive index in the low refractive index regions 1 and 2 is adjusted by the thickness and depth of the oxidized region of Al. Can do. Optimum dimensions and effective refractive index differences so that the coupling between the fundamental transverse mode and the gain region in the direction of setting the polarization direction is large and the coupling between the fundamental transverse mode and the gain region in the other direction is low. By setting to, a greater effect can be obtained. In addition, oxygen ion implantation into the portions corresponding to the low refractive index regions 1 and 2 can be performed in two steps with different acceleration voltages and ion currents for the respective regions.

  Further, in the surface emitting laser element of the present embodiment, the polarization direction can be controlled and set in an arbitrary direction by controlling the resist pattern during photolithography.

  The surface emitting laser element of this example oscillated in a single fundamental transverse mode having polarization in the first direction, and a high output operation could be obtained.

  FIGS. 13A and 13B are views showing a surface emitting laser element of Example 8. FIG. FIG. 13B is a diagram showing a top view of the surface emitting laser element of FIG. The surface emitting laser elements shown in FIGS. 13A and 13B are 0.98 μm band surface emitting laser elements having a GaInAs / GaAs multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process. The surface emitting laser elements of FIGS. 13A and 13B are grown by the same method and means as in the fourth embodiment.

Specifically, the device shown in FIGS. 13A and 13B includes an n-GaAs buffer layer 402 and an n-Al _0.9 Ga _0.1 As / GaAs pair on an n-GaAs substrate 401 for one period. N-Al _0.9 Ga _0.1 As / GaAs lower semiconductor distributed Bragg reflector 403, non-doped GaAs resonator spacer 404, GaInAs / GaAs multiple quantum well active layer 405, non-doped GaAs resonator spacer 406, A 20-period p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 407 is sequentially grown. Further, in the GaAs layer which is the outermost surface layer of the upper distributed Bragg reflector 407, a contact layer (not shown) having a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided.

The surface-emitting laser elements shown in FIGS. 13A and 13B have a square shape having an opening in a portion corresponding to the low refractive index region 1 shown in FIG. 13B by using a known photolithography technique after crystal growth. And a resist pattern having an opening in a portion corresponding to the low refractive index region 2, and then from the surface of the p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 407. Oxygen ion implantation is performed. Next, the oxygen ion implanted portion is selectively oxidized by heat treatment to form a low refractive index region 1 for forming an anti-waveguide structure in the central portion of the device and a low refractive index for confining a transverse mode in the peripheral portion of the device. A refractive index region 2 is formed. Here, the opening d1 of the resist pattern in the region corresponding to the low refractive index region 1 is set to 5 μm. As shown in FIG. 13B, the low refractive index region 2 (cladding region) is provided only in a pair of directions (first direction) facing each other across the laser resonance region. Here, the width d2 of the region sandwiched between the low refractive index cladding regions in the first direction is 30 μm. FIG. 13A also shows the effective refractive index in the first direction. The effective refractive index is relatively small in the portion where the low refractive index region is provided. In this embodiment, a high refractive index region is formed on both sides of a low refractive index core located in the center of the element, and a clad made of a low refractive region is provided outside the high refractive region. FIG. 13B shows the effective refractive index in the second direction. In this direction, since the cladding region is not provided, only the core located at the center of the element is a low refractive index region.

  Thereafter, the resist pattern is aligned again with the oxygen ion implanted portion to form a square resist pattern, hydrogen ions are implanted so that the implantation peak is deeper than the oxygen ion implanted portion, and the resistance of the hydrogen ion implanted portion is increased. The current confinement structure is formed. One side d3 of the resist pattern was 8 μm. Here, the high resistance region can also be formed by implanting oxygen ions instead of hydrogen ions.

  Next, a p-type electrode 311 is formed on the element surface, and after polishing the back surface of the substrate 301, an n-type electrode 312 is formed on the back surface of the substrate 301, and ohmic conduction is performed by annealing. The surface-emitting laser element b) is used.

  In the surface emitting laser element of the present embodiment, the low refractive index region 2 (cladding region) is provided only in a pair of opposing directions including the laser oscillation region. As described above, the loss due to mode leakage is reduced in the first direction in which the low refractive index cladding region is provided. On the other hand, in the second direction in which the low refractive index cladding region is not provided, loss due to mode leakage occurs. Furthermore, in the second direction, the mode distribution in the direction perpendicular to the laser oscillation direction is wide, and the coupling with the gain region is lower than that in the first direction. Further, as described above, the high-order transverse mode has a very small coupling with the gain region due to the anti-waveguide structure in both the first and second directions.

  As described above, it is possible to selectively oscillate the fundamental transverse mode having the electric field amplitude in the first direction which has a large coupling with the gain region and has a small mode leakage loss. In the surface emitting laser element of this embodiment, the polarization direction can be controlled and set in an arbitrary direction by controlling the resist pattern at the time of photoengraving.

  In the device of this example, the polarization direction was aligned in the first direction, and it was possible to obtain a single fundamental transverse mode guide up to a high output.

  FIGS. 14A and 14B are views showing a surface emitting laser element of Example 9. FIG. FIG. 14B is a diagram showing a top view of the surface emitting laser element of FIG. The surface emitting laser elements shown in FIGS. 14A and 14B are 0.98 μm band surface emitting laser elements having a GaInAs / GaAs multiple quantum well structure as an active layer. The structure will be described below according to the manufacturing process. The surface emitting laser elements of FIGS. 14A and 14B are grown by the same method and means as in the first embodiment.

Specifically, the device shown in FIGS. 14A and 14B has an n-GaAs buffer layer 402 and an n-Al _0.9 Ga _0.1 As / GaAs pair on an n-GaAs substrate 401 for one period. N-Al _0.9 Ga _0.1 As / GaAs lower semiconductor distributed Bragg reflector 403, non-doped GaAs resonator spacer 404, GaInAs / GaAs multiple quantum well active layer 405, non-doped GaAs resonator spacer 406, A 20-period p-Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector 407 is sequentially grown. Further, in the GaAs layer which is the outermost surface layer of the upper distributed Bragg reflector 407, a contact layer (not shown) having a high concentration of p-type dopant (carbon) in the vicinity of the surface is provided.

Further, a p-AlAs selectively oxidized layer 408 is provided in the p-Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As upper semiconductor distributed Bragg reflector 407 for current confinement. Yes. Here, the p-AlAs selectively oxidized layer 408 is formed with an oxidized region (a region shown in black) by performing selective oxidation from an etching end face in a heating atmosphere containing water vapor.

In the surface emitting laser elements shown in FIGS. 14A and 14B, after crystal growth, a square resist pattern having a side of 30 μm is formed by a known photolithography technique, and p-Al ₀ using a known dry etching technique. _.9 Ga _0.1 As / Al _0.15 Ga _0.85 As upper semiconductor distribution From the surface of the Bragg reflector 407, n-Al _0.9 Ga _0.1 As / Al _0.15 Ga _0.85 As lower distribution Etching of each layer up to the middle of the semiconductor Bragg reflector 403 is performed to form a square mesa.

  Next, a rectangular resist opening pattern corresponding to the low refractive index region 1 in FIG. 14B is formed in alignment with the center of the mesa, and oxygen molecule ions are implanted into the center of the mesa. Yes. Here, the width of the resist pattern is set such that one side length d6 (long side length) in the first direction is 20 μm, and one side length d5 (short side length) in the second direction is 15 μm. .

Next, after removing the resist, the p-AlAs selectively oxidized layer 414 is selectively oxidized in a direction parallel to the substrate from the etching end face toward the center of the mesa in a heated atmosphere containing water vapor to selectively oxidize the resist. A current confinement structure is formed. In addition, by the heat treatment in the selective oxidation step in the heating atmosphere containing water vapor, in the oxygen ion implantation region 413, the oxidation of the Al _0.9 Ga _0.1 As mixed crystal proceeds at the same time. A selective oxidation region by oxygen ion implantation having a relatively low refractive index as compared with the region is formed. Here, the length d3 of one side of the current confinement region (non-selective oxidation region) is 10 μm.

Next, an SiO ₂ layer 409 and an insulating resin are formed on the entire surface of the wafer. Next, a p-side electrode 411 is formed, and after polishing the back surface of the n-GaAs substrate 401, an n-side electrode 412 is provided, and ohmic conduction between both electrodes 411 and 412 is achieved by annealing.

  In the surface emitting laser element of this example, the oscillation mode distribution corresponds to the direction corresponding to the long side of the rectangle and the short side by making the shape of the low refractive index region 1 anisotropic as shown in the figure. The fundamental transverse mode distribution in a specific direction is set so as to obtain high coupling with the gain region, so that only the fundamental transverse mode having a polarization in a specific direction can be obtained. Can be selectively oscillated.

  Here, the dimension of each part can be set to a value other than that shown in this embodiment, and the effective refractive index in the low refractive index core can be adjusted by the thickness and depth of the oxidized region of Al. By appropriately adjusting the mesa, the size of the low refractive index core, and the effective refractive index, the coupling between the fundamental transverse mode and the gain region in the direction of setting the polarization direction is large, and the fundamental transverse mode and the gain region in the other direction It is possible to obtain a greater effect by optimally setting so as to reduce the coupling.

  Since the high-order transverse mode has a small electric field amplitude in the laser oscillation region, it is easily affected by the anti-waveguide structure. Therefore, by using the anti-waveguide structure, the coupling with the gain region is originally small, and the oscillation is It can be suppressed sufficiently.

  In the surface emitting laser element of this embodiment, the polarization direction can be controlled and set in an arbitrary direction by controlling the resist pattern at the time of photoengraving.

  In the present embodiment, an example of a surface emitting laser element having a rectangular low refractive index region 1 has been described. However, the low refractive index region 1 may have an elliptical shape or the like. In either case, the same effect can be obtained. In addition to the selective oxidation type, the structure of the surface emitting laser element may be the hydrogen ion implantation type shown in the sixth to eighth examples.

  The surface emitting laser element of this example oscillated in a single fundamental transverse mode having polarization in the first direction, and a high output operation could be obtained.

  In each of the above embodiments, the MOCVD method has been described as an example of the crystal growth method, but other crystal growth methods such as a molecular beam crystal growth method (MBE method) may be used. You can also. In addition to the n-type substrate and the semi-insulating substrate, a p-type substrate may be used as the substrate. Further, the oscillation wavelength may be in a wavelength band such as a 0.65 μm band, a 0.98 μm band, and a 1.5 μm band in addition to the 0.85 μm band and the 1.3 μm band described above. Further, as the semiconductor material constituting the element, other than the above may be used depending on the oscillation wavelength. For example, an AlGaInP mixed crystal can be used in the 0.65 μm band, an InGaAs mixed crystal can be used in the 0.98 μm band, and a GaInNAs (Sb) mixed crystal semiconductor can be used in the 1.5 μm band. The material of the distributed Bragg reflector may be a combination that is transparent in these wavelength bands and has a refractive index difference as large as possible. Further, the element structure may be a structure other than that shown in each of the above-described embodiments, and the element shown in each of the above-described embodiments may have other oscillation wavelengths. The material and configuration of the distributed Bragg reflector are optimally selected according to the oscillation wavelength, and any structure can form an element corresponding to an arbitrary oscillation wavelength.

  In order to further reduce the resistance of the element, it is effective to provide a hetero spike buffer layer having a composition between them at the hetero interface such as Al (Ga) As / GaAs. A hetero spike buffer layer may also be provided at the interface of the layers. Examples of the hetero spike buffer layer include a single layer having a composition between two layers constituting a hetero interface, a combination of a plurality of layers having different compositions, and a composition whose composition is continuously changed.

  FIG. 15 is a view showing a surface emitting laser array of Example 10. In FIG. That is, FIG. 15 is a top view of a monolithic laser array in which 4 × 4 surface emitting laser elements of the present invention are integrated two-dimensionally. In FIG. 15, in order to drive each surface emitting laser element independently, wiring is individually provided on the upper electrode. The surface emitting laser array of FIG. 15 is manufactured by the same procedure and method as in any of the previous embodiments.

  The individual elements constituting the surface emitting laser array of FIG. 15 have an anti-waveguide structure composed of a low refractive index layer formed by oxygen ion implantation and heat treatment in the resonator structure as shown in the first to fourth embodiments. Since the high-order transverse mode is suppressed very efficiently, the surface emitting laser array of FIG. 15 can obtain a high output in the single fundamental transverse mode. In addition, the surface emitting laser array in which the anti-waveguide structure is provided in the n-conduction type distributed Bragg reflector has a low resistance and a high output operation. Therefore, it oscillated in the single fundamental transverse mode up to high output with little heat generation. As described above, a surface emitting laser array that operates at a high output in a single transverse mode was obtained.

  FIG. 16 is a diagram illustrating an example of a surface emitting laser module, and FIG. 17 is a diagram illustrating an example (Example 11) of an inter-device parallel optical interconnection system.

  The laser array module of FIG. 16 is configured by mounting a one-dimensional monolithic surface emitting laser array of the present invention, a microlens array, and a fiber array on a silicon substrate. Here, the surface emitting laser array is provided facing the fiber, and is coupled to a quartz single mode fiber mounted in a V-groove formed in the silicon substrate via a microlens array. The oscillation wavelength of the surface emitting laser array is 1.3 μm band, and high-speed transmission can be performed by using a quartz single mode fiber.

  In addition, the interconnection system of FIG. 17 is configured by connecting the devices 1 and 2 using an optical fiber array. The device 1 on the transmission side includes a one-dimensional laser array module using the surface-emitting laser element or the surface-emitting laser array of the present invention and a drive circuit for the one-dimensional laser array module. The device 2 on the receiving side includes a photodiode array module and a signal detection circuit.

  In addition, the optical interconnection system of Example 11 uses the surface emitting laser array of the present invention, so that it stably oscillates in the fundamental transverse mode against changes in driving conditions such as environmental temperature, and is coupled to the fiber. There was little change in the rate, and a highly reliable interconnection system could be constructed.

  In the eleventh embodiment, the parallel optical interconnection system has been described as an example. However, a serial transmission system using a single element can also be configured. In addition to inter-device, it can be applied to inter-board, inter-chip, and intra-chip interconnection.

  FIG. 18 is a diagram illustrating an optical communication system according to a twelfth embodiment. The optical communication system in FIG. 18 is configured as an optical LAN system.

  In the optical LAN system of FIG. 18, the surface-emitting laser element or the surface-emitting laser array of the present invention is used as a light source for optical transmission between the server and the core switch, between the core switch and each switch, and between the switch and each terminal. It has been. Each device is coupled by a quartz single mode fiber or a multimode fiber.

  In the optical LAN system of FIG. 18, the surface emitting laser element or the surface emitting laser array of the present invention is used as the light source, so that the oscillation can be stably performed in the fundamental transverse mode against changes in driving conditions such as the environmental temperature. It was possible to construct a highly reliable system with little change in coupling ratio.

  FIG. 19 shows an electrophotographic system according to the thirteenth embodiment.

  The electrophotographic system of FIG. 19 includes a photosensitive drum, a scanning convergence optical system (optical scanning system), a writing light source, and a synchronization control unit. The writing light source includes the surface emitting laser element or the surface emitting laser array of the present invention. It is used. In the electrophotographic system of FIG. 19, control is performed by a synchronous control circuit, and light from a light source is condensed on a photosensitive drum by a scanning convergence optical system including a polygon mirror and a lens convergence system to form a latent image. Conventionally, surface emitting laser elements have been difficult to operate at high output due to heat generation. However, the surface emitting laser element of the present invention can operate at a higher output than conventional elements and can be used for writing in an electrophotographic system. It can be used as a light source. Further, since the oscillation mode is also a single basic transverse mode, the far-field image is unimodal, and high-definition image quality can be obtained because the beam is easily condensed.

  Further, a red surface emitting laser element using an AlGaInP-based material as an active layer material can oscillate at a short wavelength of about 650 nm as compared with an AlGaAs-based material, and can increase the margin of optical design. Therefore, it is suitable as a writing light source for a high-definition electrophotographic system. Such a red surface emitting laser element can be configured using an AlGaInP-based material for the active layer and an AlGaAs or AlGaInP-based material for the distributed Bragg reflector. In addition, since these materials can be crystal-growth by lattice matching with a GaAs substrate, an AlAs material or the like can be used as a selective oxidation layer. However, AlGaInP-based materials are very susceptible to temperature changes, and problems such as output saturation and oscillation stoppage due to temperature rise due to element heat generation. However, the surface emitting laser device fabricated using the present invention oscillates the high-order transverse mode by spreading the distribution of the high-order transverse mode to the mesa side due to the anti-waveguide structure and reducing the coupling of the gain region. Therefore, it is possible to provide a larger current confinement diameter than in the conventional case. Therefore, the current confinement diameter that had to be set small in the red surface emitting laser can be set larger than the conventional one, and a low-resistance element can be obtained. As described above, the element heat generation is reduced, and a high output operation is possible in the single fundamental transverse mode oscillation as compared with the conventional case. As described above, it is suitable as a writing light source for an electrophotographic system.

  In addition, since the multi-beam writing system can be obtained by using the surface emitting laser array according to the tenth embodiment, the writing speed and the like can be increased as compared with the prior art. From the above, a high-speed and high-definition electrophotographic system can be obtained.

  FIG. 20 is a diagram showing an optical disk system according to the fourteenth embodiment.

  The optical disk system of FIG. 20 includes an optical disk, an optical system 1, an optical system 2, a beam splitter, a photodetector, a laser light source, and a synchronization control unit (synchronization control circuit). Laser elements or surface emitting laser arrays are used.

  Here, the optical system 1, the optical system 2, the beam splitter, the photodetector, and the laser light source constitute an optical head and are configured to be able to access an arbitrary track of the disk by an actuator. Here, the optical system 1 is composed of a diffraction grating and a light beam magnifying lens, and the optical system 2 is composed of a quarter wavelength plate and a focusing lens.

  In the optical disk system of FIG. 20, the laser light from the laser light source controlled by the synchronization control circuit is converged on the disk surface by the optical system 1 and the optical system 2 to irradiate the disk surface. On the disk surface, information pits and tracks composed of regular arrangements of information pits, for example, are formed. For example, in a read operation, the laser light reflected on the disk surface passes through the optical system 2 again and is guided to a photodetector by a beam splitter. In the photodetector, an information signal by an information pit and a track signal are detected, and based on this, the distance between the disk and the head and the servo of the optical head with respect to the information track are performed.

Since the surface emitting laser element of the present invention can operate at a higher output in the basic single transverse mode than the conventional element, it is possible to stably obtain a unimodal beam spot, which is necessary for beam shaping. The optical system can be greatly simplified and the cost can be reduced. In addition, since a unimodal beam spot can be obtained stably, a highly reliable optical disc system can be configured. Further, when the surface emitting laser array of Example 10 is used as a laser light source, high-speed reading can be performed. As described above, a high-speed and highly reliable optical disc system can be obtained.

1 is a diagram illustrating a surface emitting laser element of Example 1. FIG. It is a figure which shows a part of area | region in which oxygen ion implantation is performed in FIG. 1 in detail. It is a figure which shows distribution of the mode with the case where there is no anti-waveguide structure and the case where it exists. 6 is a diagram for explaining a surface emitting laser element according to Example 2. FIG. 6 is a diagram for explaining a surface emitting laser element according to Example 2. FIG. 6 is a view for explaining a surface emitting laser element according to Example 3. FIG. FIG. 6 is a diagram showing another configuration example of the oxygen ion implantation region of the surface emitting laser element in Example 1. 6 is a view showing a surface emitting laser element of Example 4. FIG. 6 is a view showing a surface emitting laser element according to Example 5. FIG. FIG. 10 is a diagram showing an example in which an anti-waveguide structure is provided in an n-type distributed Bragg reflector in the surface emitting laser element of FIG. 6 is a view showing a surface emitting laser element according to Example 6. FIG. FIG. 10 is a diagram showing a surface emitting laser element of Example 7. FIG. 10 is a diagram showing a surface emitting laser element of Example 8. 10 is a diagram showing a surface emitting laser element according to Example 9. FIG. FIG. 10 is a diagram showing a surface emitting laser array of Example 10. It is a figure which shows an example of a surface emitting laser module. It is a figure which shows an example of the parallel optical interconnection system between apparatuses. FIG. 16 illustrates an optical communication system according to a twelfth embodiment. 14 is a diagram showing an electrophotographic system of Example 13. FIG. FIG. 16 is a diagram illustrating an optical disc system according to a fourteenth embodiment.

Claims (17)

An active layer, a resonator spacer layer provided on both sides of the active layer, a current confinement structure defining a current injection region to the active layer, and a pair of distributions facing each other across the active layer and the resonator spacer layer and a Bragg reflector, the surface-emission laser device current confinement structure is formed by selective oxidation, the pair of distributed Bragg reflector is constituted by AlGaAs semiconductor material, further, in the semiconductor distributed Bragg reflector In this case, a region having a spatially overlapping in the laser resonance direction with the current injection region defined by the current confinement structure is provided with a region having a relatively low refractive index with respect to the periphery, including an Al oxide. A surface emitting laser element characterized by having An active layer, a resonator spacer layer provided on both sides of the active layer, a current confinement structure defining a current injection region to the active layer, and a pair of distributions facing each other across the active layer and the resonator spacer layer And a pair of distributed Bragg reflectors made of an AlGaAs-based semiconductor material, wherein the pair of distributed Bragg reflectors is formed of an AlGaAs-based semiconductor material. and have you in the reflector, the portion having a spatial overlap in the current injection region and the laser resonance direction defined by the current confinement structure, containing an oxide of Al, a relatively low refractive index with respect to the peripheral A surface emitting laser element characterized in that a region is provided. A surface light emission having an active layer, a current confinement structure defining a current injection region into the active layer, and a pair of distributed Bragg reflectors facing each other with the active layer interposed therebetween, wherein the current confinement structure is formed by selective oxidation In the laser element, the surface emitting laser element includes an AlGaAs mixed crystal layer constituting a distributed Bragg reflector, and a part of the AlGaAs mixed crystal layer includes a current injection region defined by the current confinement structure and a laser resonance direction. The region of the AlGaAs mixed crystal layer having a spatial overlap in the region and the current injection region defined by the current confinement structure and the spatial overlap in the laser resonance direction is selectively ion-implanted and ion-implanted with molecules containing oxygen. In the peripheral region where oxygen implantation of molecules containing oxygen in the same plane perpendicular to the laser resonance direction is not performed by the subsequent heat treatment, an Al oxide is included. Surface-emitting laser element, characterized in that to form a low free relatively refractive index region. An active layer, a current confinement structure that defines a current injection region to the active layer, and a pair of distributed Bragg reflectors across the active layer, the current confinement structure being formed by a high resistance region by ion implantation In the surface emitting laser element to be formed, the surface emitting laser element includes an AlGaAs mixed crystal layer constituting a distributed Bragg reflector , and a part of the AlGaAs mixed crystal layer is current injection defined by the current confinement structure. The region of the AlGaAs mixed crystal layer having a spatial overlap in the laser resonance direction with the region and the current injection region defined by the current confinement structure and the spatial overlap in the laser resonance direction is a selective region of oxygen-containing molecules. Peripheral regions where oxygen-implanted molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted by ion implantation and heat treatment after ion implantation. The surface emitting laser element, wherein the forming the lower region relatively refractive index containing an oxide of Al. 5. The surface emitting laser element according to claim 3, wherein the refractive index is relatively low with respect to a peripheral region in which ions of molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted. A surface emitting laser element, wherein a GaAs layer or a GaInP mixed crystal layer is provided in contact with the AlGaAs mixed crystal layer forming the region in a laser resonance direction. 5. The surface emitting laser element according to claim 3, wherein the refractive index is relatively low with respect to a peripheral region in which ions of molecules containing oxygen in the same plane perpendicular to the laser resonance direction are not implanted. The AlGaAs mixed crystal layer forming the region is provided at a position corresponding to the antinode of the standing wave of the oscillation light in the resonator structure, and is relatively in comparison with other AlGaAs mixed crystal layers constituting the element. A surface emitting laser element characterized by being highly doped. 7. The surface emitting laser element according to claim 1, wherein the region having a relatively low refractive index is provided in an n-type distributed Bragg reflector of a pair of distributed Bragg reflectors. A surface-emitting laser element characterized by that. 8. The surface-emitting laser element according to claim 1, wherein a periphery of a region having a relatively low refractive index provided with a spatial overlap in the laser resonance direction with the laser resonance region. A high refractive index region having a high refractive index with respect to the relatively low refractive index region, and a cladding having a low refractive index with respect to the high refractive index region around the high refractive index region. A surface emitting laser element characterized in that a region is provided. 9. The surface emitting laser element according to claim 8, wherein anisotropy is provided in the width of the high refractive index region surrounded by the cladding region. 9. The surface emitting laser element according to claim 8, wherein the cladding region is provided only in a pair of directions perpendicular to a laser resonance direction facing each other across the laser resonance region. The surface-emitting laser element according to any one of claims 1 to 10, wherein the region having a relatively low refractive index provided with a spatial overlap with a laser resonance region has an anisotropic shape. A surface-emitting laser element characterized by having. 12. The surface emitting laser element according to claim 1, wherein the active layer is composed of a group III-V element, and the group III element constituting the active layer is any of Ga and In. Or a surface emitting laser element characterized by containing any or all of As, N, Sb, and P as a group V element. A surface-emitting laser array, wherein the surface-emitting laser elements according to any one of claims 1 to 12 are arranged in an array. An optical interconnection system, wherein the surface-emitting laser element according to any one of claims 1 to 12 or the surface-emitting laser array according to claim 13 is used as a light source. An optical communication system, wherein the surface-emitting laser element according to any one of claims 1 to 12 or the surface-emitting laser array according to claim 13 is used as a communication light source. An electrophotographic system, wherein the surface emitting laser element according to any one of claims 1 to 12 or the surface emitting laser array according to claim 13 is used as a light source for writing. An optical disk system, wherein the surface emitting laser element according to any one of claims 1 to 12 or the surface emitting laser array according to claim 13 is used as a read / write light source.

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