JP2005189525A - Optically attenuating optical waveguide material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optically attenuating optical waveguide material which can inexpensively and simply be used for an optically attenuating part and is used to reduce fluctuation in an optical attenuation factor caused by the polarization condition of incident light beams (waveguided light beams) and to provide a manufacturing method of the material and an optically attenuating optical waveguide part using the material. <P>SOLUTION: In the optical waveguide portion of the optical waveguide material, the portion is irradiated with femtosecond laser light beams so that the polarization direction is made approximately parallel to the optical waveguide direction or irradiated with the femtosecond laser light beams so that the irradiating direction or the polarization direction of the beams are mutually made approximately orthogonal to each other at the irradiation point pairs made of n sets of two irradiation points and a structure change section is induced at the optical waveguide portion by the femtosecond laser light beams. In the optically attenuating optical waveguide material, the polarization depending loss of infrared light beams having a wavelength of 1.55μm is made equal to or less than 0.4dB. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical attenuating optical waveguide material and an optical attenuating optical waveguide material used for optical waveguide components such as an optical fixed attenuator that attenuates the intensity of an optical signal at a predetermined rate in the field of optical communication and the like. The present invention relates to a method and an optical attenuating optical waveguide component.

  An optical fixed attenuator used for the purpose of giving a predetermined attenuation factor to the power of an optical signal and adjusting the level of the optical power to an appropriate range is an important device in an optical communication system.

  Conventionally, in an optical fixed attenuator using an optical fiber as an optical waveguide material, a method of attenuating the power of an optical signal by adding a transition metal ion such as Co as a dopant inside the optical fiber is known. This optical attenuator uses an optical attenuating optical fiber in which transition metal ions such as Co are added to the optical waveguide part (core) of the optical fiber, and utilizes the optical absorption characteristics of the transition metal ions with respect to the optical communication wavelength. By doing so, a predetermined light attenuation rate is obtained (for example, see Patent Document 1).

In recent years, various kinds of glass, plastics and the like have been used by utilizing light of a large peak power obtained when condensing ultrashort pulse laser light having a pulse width of about 1000 femtoseconds (1000 × 10 ⁻¹⁵ seconds) or less. It has been reported that a structural change part in which an optical damage such as an increase in refractive index, a void or a microcrack, etc. is induced is formed at an arbitrary position in the transparent material. Formation of such a spatially selective structure changing portion using ultrashort pulse laser light produces a three-dimensional optical memory (for example, see Patent Document 2), an optical waveguide (for example, see Patent Document 3), and the like. Has been applied for. Further, a spatially selective material modification method using such an ultrashort pulse laser beam is applied to an optical attenuating optical fiber in which a refractive index increasing portion and / or an optically damaged portion are formed in the core region of the optical fiber. It is disclosed that the method has been applied to manufacture (see, for example, Non-Patent Document 1).
Japanese Patent No. 3271886 JP-A-8-220688 Japanese Patent Laid-Open No. 9-311237 Yusuke Himei and 5 others, "Induced phenomenon of femtosecond laser irradiation to optical fiber and fabrication of new optical attenuator", Proceedings of the 50th Joint Conference on Applied Physics, March 27-30, 2003 , (No. 3, P1294, 28p-K-3)

  However, in order to obtain an optical attenuating optical fiber used in the optical fixed attenuator described in Patent Document 1, it is necessary to produce a special fiber preform doped with a transition metal ion such as Co. In addition, since the optical attenuation factor depends on the concentration of transition metal ions added to the core, a dedicated fiber preform is required depending on the desired optical attenuation factor and the standard length of the fixed optical attenuator. . As a result, the fixed optical attenuator using this type of optical attenuating optical fiber is generally expensive.

  In addition, the optical attenuating optical fiber in Non-Patent Document 1 utilizes a phenomenon in which signal light is scattered or reflected in a structural change portion formed by condensing and irradiating femtosecond laser light onto the core portion of the optical fiber. doing. However, when the above optical attenuating optical fiber is used in an optical communication system, the optical attenuation rate varies greatly depending on the polarization state of incident light (guided light). There is a problem that it causes deterioration of polarization characteristics of various optical devices used in Japan.

  The present invention has been made in view of the above circumstances, and can be used for an optical attenuating optical waveguide component having any optical attenuation factor at low cost and easily, and the optical attenuation factor depending on the polarization state of incident light (guided light). An object of the present invention is to provide an optical attenuating optical waveguide material in which fluctuations are reduced, a manufacturing method thereof, and an optical attenuating optical waveguide component using the same.

  The light attenuating optical waveguide material of the present invention has a structural change portion induced by femtosecond laser light in the optical waveguide portion, and the polarization dependent loss of infrared light having a wavelength of 1.55 μm is 0. It is characterized by being 4 dB or less.

  The method for producing an optical attenuating optical waveguide material of the present invention is characterized in that femtosecond laser light is irradiated in an optical waveguide portion of the optical waveguide material so that the polarization direction thereof is substantially parallel to the optical waveguide direction. .

  In addition, the method for producing an optical attenuating optical waveguide material according to the present invention provides an optical attenuating property in which even (2n) or odd (2n + 1) irradiation points are irradiated with femtosecond laser light in the optical waveguide portion of the optical waveguide material. A method for producing an optical waveguide material, wherein femtosecond laser light is irradiated so that the irradiation direction or polarization direction of femtosecond laser light at an irradiation point pair consisting of n sets of two irradiation points is substantially orthogonal to each other. It is characterized by.

  The optically attenuating optical waveguide component of the present invention has a structural change part induced by femtosecond laser light in the optical waveguide part, and the polarization dependent loss of infrared light having a wavelength of 1.55 μm is 0. It is characterized by using an optical attenuating optical waveguide material that is 4 dB or less.

  Since the optical attenuating optical waveguide material of the present invention has a structural change portion induced by femtosecond laser light in the optical waveguide portion, it can be used for optical attenuating optical waveguide components of any optical attenuation factor. That is, the structural change portion is formed by an optical damage portion such as a refractive index increasing portion and / or a void, and attenuates light by scattering or reflecting the guided light. It can be easily adjusted by the number, the amount of change in refractive index induced in the structure change portion, the size of the structure change portion, and the like. Since the polarization-dependent loss of infrared light having a wavelength of 1.55 μm is 0.4 dB or less, when used in an optical fixed attenuator, the fluctuation of the optical attenuation factor due to the polarization state of incident light (guided light) may vary. This reduces the deterioration of the polarization characteristics of various optical devices used in the optical communication system.

  Here, the polarization-dependent loss is the amount of fluctuation of the optical loss due to the change in the polarization state of the light incident on the optical device, and the maximum and minimum values of the transmitted light power with respect to the change in the polarization state of the incident light. And is defined by the following equation:

Polarization dependent loss (dB)
= ₁₀ log ₁₀ (P _max ) −10 log ₁₀ (P _min )
P _max : Maximum transmitted light power (mW), P _min : Minimum transmitted light power (mW)
The method for producing an optical attenuating optical waveguide material according to the present invention irradiates femtosecond laser light in the optical waveguide portion of the optical waveguide material so that the polarization direction thereof is substantially parallel to the optical waveguide direction. When the numerical aperture of the condensing lens for converging light is smaller than 0.5, the polarization dependent loss is 0.4 dB or less.

  In addition, the method for producing an optical attenuating optical waveguide material according to the present invention provides an optical attenuating property in which even (2n) or odd (2n + 1) irradiation points are irradiated with femtosecond laser light in the optical waveguide portion of the optical waveguide material. An optical waveguide material manufacturing method for irradiating femtosecond laser light so that the irradiation direction or polarization direction of femtosecond laser light at an irradiation point pair consisting of n sets of two irradiation points is substantially orthogonal to each other When the numerical aperture of the condenser lens for converging femtosecond laser light is 0.5 to 1.4, the polarization dependent loss is 0.4 dB or less.

  According to the manufacturing method of the optical attenuating optical waveguide material described above, it is not necessary to prepare a special optical fiber preform containing a transition metal ion such as Co, and it is manufactured using a general communication optical fiber. be able to. Thereby, a light attenuating optical waveguide material can be manufactured at low cost. Furthermore, since the optical attenuation rate can be adjusted by changing the peak power density, irradiation time, number of irradiation points, etc. at the focal point of the femtosecond laser beam, light-attenuating optical waveguide materials with different optical attenuation factors can be easily used. Can be produced.

  In the light attenuating optical waveguide material of the present invention, when the polarization dependent loss of infrared light is 0.2 dB or less, there is almost no variation in the optical attenuation factor due to the polarization state of incident light (guided light). It can be used for a polarization-independent optical attenuating optical waveguide component.

  In addition, when the light attenuation optical waveguide material of the present invention has a reflection attenuation amount of infrared light having a wavelength of 1.3 to 1.6 μm of 45 to 70 dB, the reflected return light can be ignored in practical use. Even if it is used for an optical attenuating optical waveguide component, an optical device such as an optical isolator or an optical circulator is not required. The return loss is a decibel (dB) display of the rate at which the power of the optical signal decreases due to reflection from the optical component, and is defined by the ratio of the incident light power and the reflected light power at the incident end by the following equation. Is done.

Return loss (dB) = − ₁₀ log ₁₀ (P _r / P _i )
P _r : reflected light power (mW), P _i : incident light power (mW)
From this equation, it can be seen that the amount of return loss decreases as the reflected light power increases.

  Further, the light attenuating optical waveguide material of the present invention has a plurality of structural change portions, and if the structure change portions are formed at intervals so as not to overlap, the structure change portions are formed at equal intervals. Even if they are formed at different intervals, the optical attenuation factor, reflection attenuation amount, and polarization-dependent loss can be controlled with high accuracy. More preferably, the interval between adjacent structural change portions is 20 μm or more. In addition, the space | interval of an adjacent structure change part points out the distance between the centers of a structure change part.

  Further, when the optical attenuating optical waveguide material has an optical fiber shape, it is suitable for a connector-shaped optical fixed attenuator fixed in a ferrule.

  Next, the manufacturing method of the light attenuating optical waveguide material of the present invention will be described in detail.

As shown in FIG. 1, since the femtosecond laser beam 10 is generally linearly polarized light, it has a polarization direction 10a. In the present invention, the femtosecond laser beam 10 is converged by the condensing lens 11 and 2n (or 2n + 1) irradiation points (a ₁ , a ₂ , a ₃ , _{a 4 ··· a 2n-3,} a 2n-2, a 2n-1, a 2n, in (a _{2n +} 1)), sequentially irradiated as follows.

Here, the direction in which the femtosecond laser beam 10 is applied to the optical waveguide material 12 is an irradiation direction 10b, and the direction in which infrared light is guided in the optical waveguide portion 12a is an optical waveguide direction 12ab. Two irradiation points are set as irradiation point pairs (A ₁ , A ₂ ... A _n−1 , A _n ). Specifically, the irradiation points a ₁ and a ₂ are set as the irradiation point pair A ₁ , the irradiation point pair A ₂ between the irradiation points a ₃ and a ₄ ,..., The irradiation points a _2n-3 and a _2n−. and ₂ and the irradiation point pairs a _n-1, the irradiation point a _2n-1 and a _2n and the irradiation point pairs a _n.

  When the femtosecond laser beam 10 is converged by the condensing lens 11 having an aperture ratio smaller than 0.5, the femtosecond laser beam 10 is converted into a half-wave plate or the like in the optical waveguide portion 12a of the optical waveguide material 12. Irradiation is performed using the phase plate 13 so that the polarization direction 10a thereof is substantially parallel to the optical waveguide direction 10ab. In this case, the polarization dependent loss becomes 0.4 dB or less, and an optical attenuating optical waveguide material having any optical attenuation factor can be easily manufactured.

  On the other hand, when the femtosecond laser beam 10 is converged by the condenser lens 11 having an aperture ratio of 0.5 to 1.4, the irradiation is performed so that the polarization direction 10a is substantially parallel to the optical waveguide direction 10ab. If the direction 10b is the same, it is not preferable because the polarization dependent loss increases as the number of irradiation points increases (as the light attenuation factor increases). In particular, when there are five or more irradiation points, the polarization dependent loss tends to be larger than 0.4 dB.

Therefore, when the femtosecond laser beam 10 is converged by the condensing lens 11 having an aperture ratio of 0.5 to 1.4, if an optical attenuating optical waveguide material is produced by the procedure described below, a polarization dependent loss is obtained. Becomes 0.4 dB or less. First, the femtosecond laser beam 10 is irradiated to the irradiation point a ₁ . At the irradiation point a ₂ , the femtosecond laser beam 10 is rotated 90 ° around the optical waveguide material 12 with the optical waveguide portion 12 a as an axis so that the irradiation directions 10 b of the irradiation points a ₁ and a ₂ are substantially orthogonal to each other. Rotate and irradiate. Alternatively, the light source 14 of the femtosecond laser beam 10 may be irradiated by being rotated by 90 ° along the circumference 12 b of the optical waveguide material 12. Alternatively, at the irradiation point a ₂ , the optical waveguide material 12 or ½ wavelength with the irradiation direction at the irradiation point a ₁ as an axis so that the polarization directions 10 a of the irradiation point a ₁ and the irradiation point a ₂ are substantially orthogonal to each other. Irradiation is performed by rotating the phase plate 14 such as a plate by 90 °. By performing this operation similarly for the remaining irradiation point pairs, 2n or 2n + 1 structural change portions (b ₁ , b ₂ , b ₃ , b ₄ ... B _2n-3 , b _2n-2 , An optical attenuating optical waveguide material 15 having b _2n−1 , b _2n , (b _{2n + 1} )) is produced. As the irradiation point pair, in addition to selecting two adjacent irradiation points as described above, two irradiation points that are not adjacent may be selected.

  Further, when the femtosecond laser beam 10 is converged by the condenser lens 11 having an aperture ratio of 0.5 to 1.4, the femtosecond laser beam 10 is n in the first half of 2n or 2n + 1 irradiation points. Irradiation is performed such that the irradiation direction 10b and / or polarization direction 10a of the femtosecond laser light 10 at the same irradiation point is the same, and then the remaining irradiation points of the first femtosecond laser light 10 are irradiated with respect to the irradiation direction 10b. Among them, the optical waveguide material 12 is irradiated by rotating 90 ° about the optical waveguide portion 12a so that the irradiation direction 10b of the femtosecond laser beam 10 at the n irradiation points in the latter half is substantially orthogonal. Alternatively, the light source 13 of the femtosecond laser beam 10 may be irradiated by being rotated by 90 ° along the circumference 12 b of the optical waveguide material 12. Alternatively, the irradiation direction at the n irradiation points in the first half so that the polarization direction 10a of the femtosecond laser light 10 at the n irradiation points in the second half is substantially orthogonal to the irradiation direction 10b of the femtosecond laser light 10 in the first half. Irradiation is performed by rotating the optical waveguide material 12 or the phase plate 13 such as a half-wave plate by 90 ° about the axis 10b.

  According to such an irradiation method, an operation of rotating the light source 14 by 90 ° along the circumference 12b of the optical waveguide material 12 or an operation of rotating the phase plate 13 such as the optical waveguide material 12 or a half-wave plate by 90 °. Can be limited to the minimum number of times (one time), and the light-attenuating optical waveguide material 15 can be efficiently produced.

  Further, the method of manufacturing the optical attenuating optical waveguide material according to the present invention irradiates the optical waveguide portion of the optical waveguide material with femtosecond laser light through a lens having a numerical aperture of 0.5 to 1.4, thereby changing the structure changing portion. Is preferable because an optical attenuating optical waveguide material having a reflection attenuation of infrared light having a wavelength of 1.3 to 1.6 μm and a wavelength of 45 to 70 dB can be obtained. That is, when a lens having a numerical aperture of 0.5 to 1.4 (preferably 0.5 to 1.0) is used, the beam size at the focal point (irradiation point) of the femtosecond laser beam is reduced and formed. This is because the size of the structure change portion is reduced, so that the return loss of infrared light is increased (the reflected return light is reduced). Further, even if the size of the formed structure change portion is reduced, the peak power density at the focal point (irradiation point) of the femtosecond laser light is large, and the increase in the refractive index of the structure change portion is remarkable. The effect of scattering or reflecting (infrared light) increases, and the ability to attenuate guided light does not decrease. If a lens with a numerical aperture smaller than 0.5 is used, the beam size at the focal point (irradiation point) of the femtosecond laser beam tends to increase, so the size of the structural change portion increases and the return loss of infrared light. Becomes smaller than 45 dB. If a lens having a numerical aperture larger than 1.4 is used, the peak power density at the focal point (irradiation point) of the femtosecond laser light tends to increase, and the damage to the structure change portion increases. Further, the focal length of the lens is shortened, and the focal point of the femtosecond laser beam does not reach the irradiation point of the optical waveguide portion, which is not preferable.

  If the femtosecond laser beam is an ultrashort pulse laser beam having a pulse width of 10 to 1000 femtoseconds and a wavelength of 0.25 to 3 μm, it is easy to form a structural change portion in the optical waveguide portion of the optical waveguide material. Therefore, it is preferable. That is, when the pulse width exceeds 1000 femtoseconds, even if focused irradiation is performed, the peak power density at the focal point (irradiation point) becomes small, and it is difficult to form the structure change portion. When the pulse width is shorter than 10 femtoseconds, the peak power density at the focal point (irradiation point) becomes too high, and damage to the optical waveguide material increases, and the optical attenuation factor, return loss, and polarization are increased. Control of dependency loss tends to be difficult.

The peak power density at the focal point (irradiation point) of the femtosecond laser light is preferably 1 × 10 ^{8 to} 9 × 10 ¹⁵ W / cm ² . If the peak power density is less than 1 × 10 ⁸ W / cm ² , it is difficult to form the structure change portion. On the other hand, if the peak power density is larger than 9 × 10 ¹⁵ W / cm ² , damage to the structural change portion is increased, which is not preferable. A preferable range of the peak power density is 1 × 10 ¹⁴ to 1 × 10 ¹⁵ W / cm ² . The peak power of femtosecond laser light is expressed by the power (W) obtained by dividing the output energy (J) per pulse by the pulse width (second), and the peak power density at the focal point is the beam unit area at the focal point. (cm ²⁾ represented by the peak power per (W / cm ^2).

  The irradiation time for irradiating the optical waveguide portion of the optical waveguide material with the femtosecond laser light varies depending on the material of the optical waveguide material or the irradiation condition of the femtosecond laser light. It is preferable because of less damage. Moreover, a structure change part can be easily formed as irradiation time is 0.001 second or more.

  The optical waveguide material is glass, crystal, plastic, or an optical fiber or optical waveguide made of these materials that transmits light with a wavelength of 250 to 3000 nm. By using an optical microscope, the femtosecond laser can be easily used. This is preferable because the irradiation point of light can be confirmed and the structure change portion can be easily formed at a desired position.

  When the optically attenuating optical waveguide component of the present invention uses a ferrule that transmits light having a wavelength of 250 to 3000 nm, even if the optical fiber is inserted and fixed in the ferrule inner hole, it can be visually observed using an optical microscope. It becomes easy to focus the femtosecond laser beam on the irradiation point of the core part, and the femtosecond laser beam is focused and irradiated on the irradiation point of the core part of the optical fiber through the ferrule to form a structural change portion at a desired position. can do. Further, there is an advantage that the optical fiber is not easily broken during handling, and the optical fiber is easily fixed when irradiated with femtosecond laser light.

  The present invention will be described in detail based on examples. Table 1 shows Examples 1 to 7, and Table 2 shows Examples 8 to 11 and Comparative Examples 1 to 4. FIG. 2 is an explanatory view showing a method for manufacturing the optical attenuating optical fiber of the present invention.

  As shown in FIG. 2, a commercially available silica glass single-mode optical fiber 20 (outer diameter 125 μm) as an optical waveguide material is fixed on an XYZ stage 22 that enables precise control of the position using a computer 21. A femtosecond laser beam 23 having a wavelength of 800 nm, a pulse width of 120 femtoseconds, a pulse repetition period of 200 kHz, and an average power of 400 mW is applied to a core portion 20a (diameter 10 μm), which is an optical waveguide portion of the fiber 20, with the numerical aperture shown in the table. Examples 1 to 4 and Comparative Example 1 having the number of structural change portions 30a corresponding to the number of irradiation points 20ab, which are irradiated at intervals of 200 μm at the irradiation time per irradiation point 20ab shown in the table using the lens 24. -3 optical attenuating optical fibers 30 were obtained.

  Further, the optical attenuation characteristics of Examples 5 to 11 and Comparative Example 4 were the same as Example 1 except that femtosecond laser light 23 having a wavelength of 800 nm, a pulse width of 120 femtoseconds, a pulse repetition period of 1 kHz, and an average power of 5 mW was used. An optical fiber 30 was obtained.

  In Examples 1 to 7, the half-wave plate 25 was used so that the polarization direction 23a of the femtosecond laser light 23 and the optical waveguide direction 20b of the core portion 20a were substantially parallel. In Examples 8 to 11, the femtosecond laser beam 23 is irradiated at the first half of the irradiation point 20ab without changing the polarization direction 23a and the irradiation direction 23b, and the femtosecond at the first half of the irradiation point 20ab. The irradiation was performed by rotating the optical fiber 20 by 90 ° about the core portion 20a of the optical fiber 20 so that the irradiation direction 23b at the irradiation point 20ab in the latter half of the irradiation direction 23b of the laser beam 23 was orthogonal. In Comparative Examples 1, 2, and 4, a quartz crystal depolarization plate (not shown) was used so that the polarization state of the femtosecond laser beam 23 was canceled and the polarization state was not polarized. For Comparative Example 3, the half-wave plate 25 was used so that the polarization direction 23a of the femtosecond laser light 23 and the optical waveguide direction 20b of the core portion 20a were substantially orthogonal.

  The average power of the femtosecond laser beam 23 was adjusted by an ND (Neutral Density) filter 26, and the irradiation time was adjusted by a shutter 27.

  The optical attenuation rate of infrared light having a wavelength of 1.55 μm in the optical attenuating optical fiber is determined by using a laser light source built-in power meter (Anritsu MT9810A) connected to both ends of the optical attenuating optical fiber 30 fixed on the XYZ stage 22. And evaluated.

  Polarization-dependent loss of infrared light having a wavelength of 1.55 μm was evaluated using a polarization scrambler (Q8163 manufactured by Advantest) and a power meter (main body manufactured by Advantest: Q8221, laser light source: Q81212DFB, sensor: Q82233). .

  The reflection attenuation amount of infrared light having a wavelength of 1.55 μm was evaluated by using a backscattered light measurement device (MW9070B manufactured by Anritsu) connected to one end of a light attenuating optical fiber 30 fixed on the XYZ stage 22.

  As is clear from Table 1, Examples 1 to 11 are optically attenuating optical fibers having different optical attenuation factors by changing the irradiation time of the femtosecond laser light, the number of irradiation points, the numerical aperture of the condenser lens, and the like. I was able to. The polarization dependent loss was small. In particular, in Examples 8 to 11, the return loss rate was larger than 45 dB.

  On the other hand, Comparative Examples 1-4 had a large polarization dependent loss.

  As described above, the optical attenuating optical waveguide material of the present invention can be used for optical attenuating optical waveguide components having any optical attenuation factor at low cost and easily, and the optical attenuation due to the polarization state of incident light (guided light). Since the optical attenuation characteristic of the optical waveguide component is difficult to change, it is suitable for an optical fixed attenuator and an optical waveguide device.

It is a conceptual diagram which shows the manufacturing method of the light attenuating optical waveguide material in this invention. It is explanatory drawing which shows the manufacturing method of the optical attenuating optical fiber of the Example in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 23 Femtosecond laser beam 10a, 23a Polarization direction 10b, 23b Irradiation direction 11 Condensing lens 12 Optical waveguide material 12a Optical waveguide part 12ab, 20b Optical waveguide direction 12b Circumference 13 Light source 14 Phase plate 15 Optical attenuating optical waveguide material 20 Single-mode optical fiber made of silica glass 20a Core portion 20ab Irradiation point 21 Control computer 22 XYZ stage 24 Objective lens 25 1/2 wavelength plate 26 ND (Neutral Density) filter 27 Shutter 30 Light-attenuating optical fiber 30a Structure changing portion

Claims (9)

  An optically attenuating optical waveguide material having a structural change portion induced by femtosecond laser light in an optical waveguide portion, and a polarization dependent loss of infrared light having a wavelength of 1.55 μm being 0.4 dB or less.   The light attenuating optical waveguide material according to claim 1, which has an optical fiber shape.   A method for producing a light-attenuating optical waveguide material, wherein femtosecond laser light is irradiated in an optical waveguide portion of an optical waveguide material so that the polarization direction is substantially parallel to the optical waveguide direction.   A method of manufacturing a light-attenuating optical waveguide material in which an even number (2n) or an odd number (2n + 1) irradiation points are irradiated with femtosecond laser light in an optical waveguide portion of an optical waveguide material, A method for producing a light-attenuating optical waveguide material, wherein the irradiation direction or the polarization direction of femtosecond laser light at an irradiation point pair consisting of n sets of two irradiation points is irradiated so as to be substantially orthogonal to each other.   Irradiate femtosecond laser light so that the irradiation direction and / or polarization direction of femtosecond laser light at the n irradiation points are the same, and the remaining irradiation with respect to the irradiation direction or polarization direction of the femtosecond laser light The method for producing a light attenuating optical waveguide material according to claim 4, wherein irradiation is performed so that the irradiation direction or the polarization direction of femtosecond laser light at n irradiation points among the points is substantially orthogonal.   The method for producing a light-attenuating optical waveguide material according to claim 4 or 5, wherein the femtosecond laser light has a pulse width of 10 to 1000 femtoseconds and a wavelength of 250 to 3000 nm.   The method for producing an optical attenuating optical waveguide material according to any one of claims 4 to 6, wherein the optical waveguide material is an optical fiber.   An optical attenuating optical waveguide component using the optical attenuating optical waveguide material according to claim 1.   The light attenuating optical waveguide component according to claim 8, wherein a ferrule that transmits light having a wavelength of 0.25 to 3 μm is used.

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