JP5647485B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module that transmits or receives an optical signal.

  The optical module 50 shown in FIG. 8 includes an internal waveguide 52 provided in a groove formed on the surface of each first substrate 51 of the light emitting (transmitting) side optical module 50A and the light receiving (receiving) side optical module 50B. An optical path changing mirror 53 formed at the tip of the groove is provided. Further, it is mounted on the surface of each first substrate 51 and emits an optical signal to the core portion of the internal waveguide 52 via the mirror portion 53, or light from the core portion of the internal waveguide 52 via the mirror portion 53. A light emitting element (optical element) 54A and a light receiving element (optical element) 54B for receiving signals are provided. Further, an external waveguide (optical fiber) 55 optically coupled to the core portion of each internal waveguide 52 of the light emitting element 54A and the light receiving element 54B is provided (see Patent Document 1). In Patent Document 1, a flexible film-like one in which a resin optical waveguide is thinned is used as an external waveguide.

  In this patent document 1, the surface of each first substrate 51 is flip-chip mounted with bumps using the light emitting surface of the light emitting element 54A and the light receiving surface of the light receiving element 54B as mounting surfaces.

  Each first substrate 51 is installed on the surface of another second substrate (interposer substrate) 56. On the surface of each second substrate 56, an IC substrate 57A on which an IC circuit for transmitting an electric signal to the light emitting element 54A is formed and an IC circuit for receiving an electric signal from the light receiving element 54B are formed. Each IC substrate 57B is mounted.

  The light emitting element 54A, the light receiving element 54B, and the IC substrates 57A and 57B of each second substrate 6 are electrically connected by wire bonding 58, respectively. Reference numeral 59 denotes a connector for electrically connecting the IC boards 57A and 57B to other circuit devices.

  By the way, it is assumed that the light emitting side optical module 50A, the light receiving side optical module 50B, and the external waveguide (optical fiber) 55 are separable, and an abnormality such as a bit error occurs in the optical communication. In this case, the light output inspection of the light emitting side optical module 50A, the light reception intensity inspection of the light receiving side optical module 50B, and the inspection of the external waveguide 55 can be individually performed. Can be repaired.

  A method of branching light from a part of an optical waveguide and monitoring it has been proposed (see Patent Document 2).

JP 2009-260227 A JP 2006-208794 A

  However, as in Patent Document 1, it is assumed that the light-emitting side optical module 50A, the light-receiving side optical module 50B, and the external waveguide (optical fiber) 55 cannot be separated, and an abnormality such as a bit error occurs in optical communication. In this case, it is impossible to individually test each of the optical modules 50A and 50B and the external waveguide (optical fiber) 55, and it is difficult to specify an abnormal location and repair it.

  Therefore, it is conceivable to adopt a method as described in Patent Document 2. However, since a part of the light used for optical communication is used, the light efficiency is lowered. Therefore, there is a concern that increasing the laser output for stabilization of the optical communication reduces the laser life.

  The present invention has been made in order to solve the above-described problem. Even if the light-emitting side optical module, the light-receiving side optical module, and the external waveguide cannot be separated from each other, the light that can easily identify an abnormal portion is provided. The purpose is to provide modules.

In order to solve the above problems, the present invention includes a mirror for optical path conversion formed on the distal end portion of the first groove formed in the surface of the silicon substrate, the silicon substrate so as to face the mirror portion An optical element mounted on the front surface side and a second groove having a substantially V-shape formed on the surface of the silicon substrate and connected to the first groove, are optically connected to the optical element via the mirror portion. The optical element includes an optical fiber having a fiber core portion to be coupled, and the optical element emits an optical signal to the fiber core portion of the optical fiber via the mirror portion, or receives an optical signal from the fiber core portion of the optical fiber via the mirror portion. in the optical module for receiving, there is a gap between the tip of the fiber core section of the said mirror unit optical fiber, light leaking from the gap, when the optical element is a light emitting element A slope that is a side surface of the second groove is reflected or diffused toward the surface of the silicon substrate, and when the optical element is a light receiving element, the slope is a boundary surface between the first groove and the second groove. The present invention provides an optical module characterized in that a photodiode that is reflected or diffused toward the surface of the silicon substrate and that detects the leakage light is mounted on the surface of the silicon substrate.

  An internal waveguide may be provided in the first groove, and the core portion of the internal waveguide and the fiber core portion of the optical fiber may be optically coupled.

  According to the present invention, the leakage light between the optical element and the optical fiber is reflected or diffused in the direction of the surface of the substrate, and the reflected or diffused leakage light is detected. For example, if leakage light can be detected between the light emitting side optical module and the optical fiber, it can be determined that the light emitting side optical module is normal, and if it can be detected between the optical fiber and the light receiving side optical module, it can be determined that the optical fiber is normal. In this way, abnormal portions of the light emitting side optical module, the light receiving side optical module, and the optical fiber can be easily identified.

  Further, since only the leaked light is used instead of the light used for the optical communication, it is not necessary to increase the laser output for the stability of the optical communication.

  In particular, when the light emitting element is flip-chip mounted on the substrate with the light emitting surface facing downward, it is difficult to confirm the operation. Therefore, by confirming or diffusing the leaked light between the light emitting element and the optical fiber toward the surface of the substrate, the operation of the light emitting element can be easily confirmed.

It is a side view of the optical module which concerns on this invention. FIG. 2 is a first substrate of the light emitting side optical module of FIG. 1, (a) is a side sectional view, (b) is a sectional view taken along line II in (a), and (c) is a sectional view taken along line II-II in (a). FIG. 2A is a perspective view of the first substrate of FIG. 2, and FIG. 3B is a perspective view in which an internal waveguide is formed. FIG. 3A is a perspective view in which a light emitting element is mounted, and FIG. 3B is a perspective view in which an optical fiber is inserted. It is the light emission side optical module which shows leak light, (a) is a schematic sectional side view, (b) is a top view of a 1st board | substrate, (c) is the III-III sectional view taken on the line of (b). It is a schematic side sectional view of a light receiving side optical module showing leakage light. It is the 1st board | substrate which mounted the photodiode, (a) is side sectional drawing, (b) is a top view. It is side surface sectional drawing of the conventional optical module.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view of an optical module 40 according to the present invention. 2A and 2B show the light-emitting side optical module 40A of FIG. 1, in which FIG. 2A is a side cross-sectional view, FIG. 2B is a cross-sectional view taken along line II in FIG. FIG. 3A and 3B show the first substrate 1. FIG. 3A is a perspective view, and FIG. 3B is a perspective view in which an internal waveguide 16 is formed. 4A and 4B show the first substrate 1, in which FIG. 4A is a perspective view in which the light emitting element 12a is mounted, and FIG. 4B is a perspective view in which the optical fiber 2 is inserted.

  In FIG. 1, the optical module 40 includes a light emitting side optical module 40A, a light receiving side optical module 40B, and an optical fiber 2 that optically couples the light emitting side and the light receiving side optical modules 40A and 40B.

  The first substrate (mount substrate) 1 of the light emitting side optical module 40A and the first substrate (mount substrate) 1 of the light receiving side optical module 40B are rigid in order to avoid the influence of heat during mounting and the stress due to the use environment. is necessary. Further, in the case of optical transmission, since optical coupling efficiency from the light emitting element to the light receiving element is required, it is necessary to mount the optical element with high accuracy and to suppress position fluctuation during use as much as possible. For this reason, a silicon (Si) substrate is employed as the first substrate 1 in the present embodiment.

  In particular, in the case of a silicon substrate, it is possible to process a highly accurate etching groove on the surface by utilizing the crystal orientation of silicon [a highly accurate mirror portion 15 (described later) using this groove, and an internal waveguide 16 ( (To be described later). ]. In addition, the silicon substrate has good flatness.

  The first substrate 1 is installed on the surface (upper surface) of a second substrate (interposer substrate) 6 having a larger size. Connectors 7 for electrically connecting to other circuit devices are respectively attached to the back surface (lower surface) of each second substrate 6.

  On the surface (upper surface) of the first substrate 1, a light emitting element 12a that converts an electrical signal into an optical signal is flip-chip mounted with bumps 12c (see FIG. 2) with the light emitting surface facing downward. An IC substrate (signal processing unit) 4a on which an IC circuit for transmitting an electrical signal to the light emitting element 12a is formed is mounted on the surface of the second substrate 6.

  In the present embodiment, a surface emitting laser (VCSEL (Vertical Cavity Surface Emitting Laser)) that is a semiconductor laser is employed as the light emitting element 12a. The light emitting element 12a may be an LED or the like.

  The IC substrate 4a is a driver IC that drives the VCSEL, and is disposed in the vicinity of the light emitting element 12a. The light emitting element 12a and the IC substrate 4a are connected to a metal circuit (patterning circuit by copper or gold sputtering) formed on the surface of the first substrate 1 and the surface of the second substrate 6.

  On the surface of the first substrate 1, as shown in FIG. 3 (a), a substantially trapezoidal first groove (waveguide forming groove) 1a and a substantially V-shaped second deeper than the first groove 1a. The groove 1b is formed continuously in the front-rear direction. The first groove 1a may be a substantially V-shaped groove that is shallower than the second groove 1b.

  At the tip of the first groove 1a, an optical path changing mirror 15 for bending the optical path by 90 degrees is formed at a position directly below the light emitting element 12a.

  As shown in FIG. 3B, an internal waveguide 16 that is optically coupled to the light emitting element 12a of the first substrate 1 is provided in the first groove 1a of the first substrate 1. The internal waveguide 16 extends from the mirror portion 15 in the direction of the second groove 1b and is flush with the rear end portion 1d of the first groove 1a.

  The internal waveguide 16 includes a core portion 17 having a substantially square cross section with a high refractive index through which light propagates, and a cladding portion 18 having a refractive index lower than that. As shown in FIG. 2C, the left and right surfaces of the core portion 17 are covered with the cladding portion 18. When the first groove 1a is a shallow V-shaped groove that is shallower than the second groove 1b, the core portion 17 is not substantially square in cross section, but is substantially pentagonal in cross section along the substantially V-shaped groove. Form into shape.

  As shown in FIG. 4A, a light emitting element 12a is mounted at a predetermined position on the surface of the first substrate 1 on which the internal waveguide 16 is provided, and the space between the light emitting element 12a and the core portion 17 is mounted. As shown in FIG. 2A, the optical transparent resin 13 is filled.

  Returning to FIG. 1, the first substrate 1 of the light-receiving side optical module 40B will be described. The basic configuration of the first substrate 1 of the light receiving side optical module 40B is the same as that of the first substrate 1 of the light emitting side optical module 40A. However, a light receiving element 12b for converting an optical signal into an electric signal is flip-chip mounted with bumps on the surface (upper surface) of the first substrate 1 of the light receiving side optical module 40B with the light receiving surface facing downward. In addition, an IC substrate (signal processing unit) 4b on which an IC circuit for transmitting an electric signal to the light receiving element 12b is mounted on the surface of the second substrate 6, and the light emitting side optical module 40A is mounted. Different from the first substrate 1. As this light receiving element 12b, PD (Photo Diode) is adopted, and the IC substrate 4b is an element such as a TIA (Trans-impedance Amplifier) that performs current / voltage conversion.

  Next, the optical fiber 2 will be described. As shown in FIG. 1 and FIG. 4B, the optical fiber 2 includes the core portion 17 of the internal waveguide 16 of the first substrate 1 of the light emitting side optical module 40A and the inside of the first substrate 1 of the light receiving side optical module 40B. A fiber core portion 21 that can be optically coupled to the core portion 17 of the waveguide 16 is provided inside. And it is a cord type comprised by the fiber cladding part 22 surrounding the outer periphery of this fiber core part 21, and the coating | coated part 23 which coat | covers the outer periphery of this fiber cladding part 22. FIG. The fiber core portion 21, the fiber clad portion 22, and the covering portion 23 are circular.

  As shown in FIG. 1, the optical fiber 2 has the covering portion 23 peeled off in the vicinity of the second groove 1 b of the first substrate 1 to expose the fiber cladding portion 22.

  Then, as shown in FIGS. 2A, 2C, and 4B, the fiber clad portion 22 of the optical fiber 2 is installed in the second groove 1b of the first substrate 1, and the boundary portion with the first groove 1a. The fiber clad portion 22 is positioned on the inclined surface 1c. At this time, it is optically coupled with the optical axis of the core part 17 of the internal waveguide 16 of the first substrate 1 and the fiber core part 21 of the optical fiber 2 being aligned.

  The gap between the end face of the core portion 17 of the internal waveguide 16 of the first substrate 1 and the end face of the fiber core portion 21 of the optical fiber 2 is 200 μm or less. In general, the gap 0 is preferable in which the optical coupling efficiency is 100%. However, in this configuration, the gap is 60 μm to 100 μm due to restrictions on the groove width of the first substrate 1 and the outer diameter size of the fiber clad portion 22. It becomes.

  At the position of the surface of the first substrate 1, as shown in FIGS. 2A and 2B, an adhesive optical transparent resin 14 is provided in the second groove 1 b in order to fix the optical fiber 2 to the first substrate 1. Is filled.

  In the light emitting side optical module 40A, an optical signal is emitted from the light emitting element 12a to the fiber core portion 21 of the optical fiber 2 via the mirror portion 15. In the light receiving side optical module 40B, the light signal from the fiber core portion 21 of the optical fiber 2 is received by the light receiving element 12b via the mirror portion 15.

  5A is a light-emitting side optical module 40A, where FIG. 5A is a schematic side sectional view, FIG. 5B is a plan view of the first substrate 1, and FIG. 5C is a sectional view taken along line III-III in FIG. The light emitting side optical module 40A of FIG. 5 is a type in which the internal waveguide 16 is not provided in the first groove 1a, and the leakage light b in the light emitting side optical module 40A in this type will be described.

  As shown in FIG. 5A, the optical signal a is emitted from the light emitting element 12 a to the fiber core portion 21 of the optical fiber 2 through the mirror portion 15. At this time, since there is a gap S between the mirror portion 15 and the tip of the fiber core portion 21 of the optical fiber 2, leaked light that does not reach the tip of the fiber core portion 21 of the optical fiber 2 as shown in FIG. b occurs.

  As shown in FIG. 5C, the leaked light b is a slope (reflecting or diffusing portion: reflecting surface or diffusing surface) 1e which is a side surface of the substantially V-shaped second groove 1b. Reflected or diffused in the surface (up) direction. Further, the light that has entered the fiber cladding portion 22 of the optical fiber 2 passes through the fiber cladding portion 22 and reaches the inclined surface 1e, and is similarly reflected or diffused.

  FIG. 6 is a schematic side sectional view of the light receiving side optical module 40B. The light receiving side optical module 40B in FIG. 6 is a type in which the internal waveguide 16 is not provided in the first groove 1a, similarly to the light emitting side optical module 40A in FIG. The leakage light c will be described.

  As shown in FIG. 6, the light signal a from the fiber core portion 21 of the optical fiber 2 is received by the light receiving element 12b via the mirror portion 15. At this time, since there is a gap S between the mirror portion 15 and the tip of the fiber core portion 21 of the optical fiber 2, leakage light c that does not reach the mirror portion 15 is generated.

  The leaked light c is an inclined surface (reflected or diffused portion: reflecting surface or diffusing surface) 1c that is a boundary surface between the first groove 1a and the second groove 1b, and the surface (upward) direction of the first substrate 1 Reflected or diffused. In addition to the inclined surface 1c, the inclined surface of the substantially trapezoidal (or substantially V-shaped) first groove 1a is similarly reflected or diffused.

  In the case of the light emitting side optical module 40A of FIG. 5, the leaked light b between the light emitting element 12a and the optical fiber 2 is reflected or diffused toward the surface of the first substrate 1 by the inclined surface 1e. The reflected or diffused leakage light b is detected by leakage light detection means (described later) arranged on the surface side of the first substrate 1.

  Further, in the case of the light receiving side optical module 40B of FIG. 6, the leaked light c between the optical fiber 2 and the light receiving element 12b is caused to have a substantially trapezoidal shape (or a substantially V shape other than the inclined surface 1c as described above). ) Including the inclined surface of the first groove 1a, and so on. The reflected or diffused leakage light c is detected by leakage light detection means (described later) disposed on the surface side of the first substrate 1.

  For example, if the leakage light b can be detected between the light emitting side optical module 40A and the optical fiber 2, the light emitting side optical module 40A can be determined to be normal, and then the leakage light c is detected between the optical fiber 2 and the light receiving side optical module 40B. If possible, it can be determined that the optical fiber 2 is normal. In this way, abnormal portions of the light emitting side optical module 40A, the light receiving side optical module 40B, and the optical fiber 2 can be easily identified. Further, since only the leaked light b and c is used instead of the light used for optical communication, it is not necessary to increase the laser output in order to stabilize the optical communication.

  In particular, since the light emitting element 12a (the same applies to the light receiving element 12b) is flip-chip mounted on the first substrate 1 with the light emitting surface facing downward, it is difficult to confirm the operation (light emission) as it is. Therefore, by reflecting or diffusing the leaked light b between the light emitting element 12a and the optical fiber 2 in the direction of the surface of the first substrate 1, the operation of the light emitting element 12a can be easily confirmed.

  Here, as a part for reflecting the leaked light b and c in the surface direction of the first substrate 1, in the light emitting side optical module 40A, the inclined surface 1e which is the side surface of the second groove 1b, and in the light receiving side optical module 40B, The slope 1c is a boundary surface between the first groove 1a and the second groove 1b.

  That is, if the first substrate 1 is a silicon substrate, each inclined surface is formed when the mirror portion 15, the first groove 1a, and the second groove 2b are simultaneously formed by etching or the like using the crystal orientation of the silicon substrate. It is also possible to simultaneously form 1e and 1c by a single etching process. The slopes 1e and 1c formed in this way ensure smoothness as an optical reflecting surface.

  As described above, when the first groove 1a and the second groove 1b are formed on the silicon substrate (first substrate 1) by etching or the like, the inclined surfaces (reflection surfaces or diffusion surfaces) 1e and 1c are simultaneously formed with high accuracy. Can do. Thereby, the leakage lights b and c can be efficiently reflected or diffused. Further, since the reflecting surface or the diffusing surface can use the inclined surfaces 1e and 1c of the first groove 1a and the second groove 1b as they are, a space for forming the reflecting surface or the diffusing surface becomes unnecessary.

  Here, in order for the silicon substrate to transmit near-infrared rays, a metal thin film (several tens of nm or more) such as Au, Al, or Ag is formed on the surfaces of the inclined surfaces 1e and 1c so as to be a reflective surface. It is preferable to do. A technique such as sputtering is effective for forming the metal thin film. Further, the same metal plating or the like may be formed when forming the circuit pattern of the light emitting element 12a or the light receiving element 12b.

  Next, the leakage light detection means will be described. Since the wavelength used for general optical communication is near infrared rays such as 850 nm, 1310 nm, and 1550 nm, the leakage lights b and c cannot be detected visually. For this reason, if an infrared camera having sensitivity corresponding to the communication wavelength is used as the leakage light detection means, the leakage lights b and c can be detected.

  However, if a fluorescent material that emits fluorescence (converts to visible light) corresponding to the communication wavelength is disposed (applied) on the inclined surfaces 1e and 1c of the first substrate 1 as a leakage light detection means, even without using an infrared camera, The leakage lights b and c can be detected visually.

  However, there is a concern that the leakage light detection means described above lacks accuracy in detecting the emission intensity. Therefore, as shown in FIG. 7, a photodiode 25 as a leakage light detection unit is formed on the surface of the first substrate 1 in correspondence with the leakage light b reflected or diffused in the surface (upward) direction of the first substrate 1. Is implemented.

  Thus, if the leakage light detection means is the photodiode 25, the communication state can be detected with higher accuracy. Further, since the photodiode 25 can detect leaked light from the normal operation, the abnormal operation can be detected quickly.

  The embodiment of FIGS. 5 to 7 is a type in which neither the light emitting side nor the light receiving side optical modules 40A and 40B are provided with the internal waveguide 16 in the first groove 1a. On the other hand, as in the embodiment shown in FIGS. 1 to 4, the inner waveguide 16 is provided in the first groove 1a in both the light emitting side and the light receiving side optical modules 40A and 40B, and the core The portion 17 and the fiber core portion 21 of the optical fiber 2 can be optically coupled.

  That is, if the optical fiber 2 is disposed immediately below the light emitting element 12a or the light receiving element 12b, the light emitting element 12a or the light receiving element 12b and the optical fiber 2 may be in contact with each other in the mounting process. Therefore, as shown in FIG. 5A, it is desirable to separate a distance (corresponding to the gap S in FIG. 5A) between the light emitting element 12a (or the light receiving element 12b) and the optical fiber 2.

  However, since the light emitted from the light emitting element 12a such as a semiconductor laser has a spread angle of about 10 degrees to 30 degrees, the efficiency of entering the optical fiber 2 is increased when the distance between the light emitting element 12a and the optical fiber 2 is increased. Deteriorate. Similarly, on the light receiving element 12b side, the light emitted from the optical fiber 2 is emitted with a spread angle depending on the numerical aperture (NA) of the optical fiber 2, so that the efficiency of entering the light receiving element 12b is deteriorated.

  Therefore, if the internal waveguide 16 is formed between the light emitting element 12a or the light receiving element 12b and the optical fiber 2, the optical coupling efficiency between the light emitting element 12a or the light receiving element 12b and the optical fiber 2 is improved. As a result, the light utilization efficiency of the entire optical module (the ratio of the amount of light reaching the light receiving element 12b from the light emitting element 12a) is increased, and the reliability of optical communication is improved.

  As described above, the optical module according to the present invention includes the optical path changing mirror portion formed at the tip portion in the first groove formed on the surface of the substrate and the surface of the substrate so as to face the mirror portion. An optical element mounted on the side, and a fiber core portion installed in a second groove formed on the surface of the substrate and connected to the first groove, and optically coupled to the optical element via the mirror portion. In the optical module, the optical element emits an optical signal to the fiber core part of the optical fiber through the mirror part, or receives an optical signal from the fiber core part of the optical fiber through the mirror part. A portion for reflecting or diffusing leakage light between the optical element and the optical fiber in the direction of the surface of the substrate is formed on the substrate, and means for detecting the leakage light is arranged on the surface side of the substrate. And it is characterized in that it is.

  According to this, the leakage light between the optical element and the optical fiber is reflected or diffused toward the surface of the substrate, and the reflected or diffused leakage light is detected. For example, if leakage light can be detected between the light emitting side optical module and the optical fiber, it can be determined that the light emitting side optical module is normal, and if it can be detected between the optical fiber and the light receiving side optical module, it can be determined that the optical fiber is normal. In this way, abnormal portions of the light emitting side optical module, the light receiving side optical module, and the optical fiber can be easily identified. Further, since only the leaked light is used instead of the light used for the optical communication, it is not necessary to increase the laser output for the stability of the optical communication. In particular, when the light emitting element is flip-chip mounted on the substrate with the light emitting surface facing downward, it is difficult to confirm the operation. Therefore, by confirming or diffusing the leaked light between the light emitting element and the optical fiber toward the surface of the substrate, the operation of the light emitting element can be easily confirmed.

  The means for detecting leakage light may be a photodiode mounted on the surface of the substrate.

  According to this, if the means for detecting leakage light is a photodiode, the communication state can be detected with higher accuracy. In addition, since the photodiode can detect the leaked light from the normal operation, it is possible to detect the abnormal operation quickly.

  The substrate is a silicon substrate, and the site for reflecting or diffusing the leakage light toward the surface of the substrate is a reflection surface or a diffusion surface formed in the first groove and the second groove of the silicon substrate. it can.

  According to this, when the first groove and the second groove are formed on the silicon substrate by etching or the like, the reflection surface or the diffusion surface can be simultaneously formed with high accuracy. Thereby, leakage light can be reflected or diffused efficiently. Further, since the reflecting surface or the diffusing surface can use the slopes of the first groove and the second groove as they are, a space for formation becomes unnecessary.

  An internal waveguide may be provided in the first groove, and the core portion of the internal waveguide and the fiber core portion of the optical fiber may be optically coupled.

  According to this, by providing the internal waveguide in the first groove, the light utilization efficiency of the entire optical module (the ratio of the amount of light reaching the light receiving element from the light emitting element) is increased, and the reliability of optical communication is improved. It becomes like this.

DESCRIPTION OF SYMBOLS 1 1st board | substrate 1a 1st groove | channel 1b 2nd groove | channel 1c, 1e Slope (site | part which reflects or diffuses leak light)
2 Optical fiber 12a Light emitting element (optical element)
12b Light receiving element (optical element)
15 Mirror part 16 Internal waveguide 17 Core part 21 Fiber core part 25 Photodiode (leakage light detecting means)
40 Optical module 40A Light emitting side optical module 40B Light receiving side optical module b, c Leakage light

Claims (2)

A mirror for optical path conversion formed on the distal end portion of the first groove formed in the surface of the silicon substrate, and an optical element mounted on the surface of the silicon substrate so as to be opposed to the mirror portion, the silicon substrate An optical fiber having a fiber core portion that is installed in a substantially V-shaped second groove formed on the surface of the first groove and is optically coupled to the optical element via the mirror portion; In the optical module, the optical element emits an optical signal to the fiber core part of the optical fiber through the mirror part, or receives an optical signal from the fiber core part of the optical fiber through the mirror part.
There is a gap between the mirror part and the tip of the fiber core part of the optical fiber,
The leaked light from this gap
When the optical element is a light emitting element, it is reflected or diffused in the direction of the surface of the silicon substrate on the slope that is the side surface of the second groove,
When the optical element is a light receiving element, it is reflected or diffused in the direction of the surface of the silicon substrate at a slope that is a boundary surface between the first groove and the second groove,
An optical module, wherein a photodiode for detecting the leakage light is mounted on a surface of the silicon substrate. The optical module according to claim 1 , wherein an internal waveguide is provided in the first groove, and a core portion of the internal waveguide and a fiber core portion of the optical fiber are optically coupled .

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