JP2005018006A - Optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of a monitor function for signal light by reducing an interference influence of light reflected by other parts on reflected light on a multi-layered surface of a filter member. <P>SOLUTION: The surface of the filter member 20 on the side of the multi-layer film 56 is defined as a 1st surface 70, and the surface of the filter member 20 on the side of a quartz substrate 54 is defined as a 2nd surface 72; and the surface of the filter member 20 which faces the 1st surface is defined as a 1st internal wall surface 74 and the surface of the filter member 20 which faces the 2nd surface 72 is defined as a 2nd internal wall surface 76. In this case, one or more surfaces among a 1st internal wall surface 74 and a 2nd internal wall surface 76 of a slit 18 and the 2nd surface 72 of the filter member 20 are not parallel to the 1st surface 70 of the filter member 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical device having one optical fiber or a plurality of optical fibers (optical fiber array), one optical waveguide, or a plurality of optical waveguides, and in particular, signal light propagating through these optical transmission means. The present invention relates to an optical device that is suitable for monitoring the device during the process.

  In the current optical communication technology, communication quality monitoring technology is an important item. In particular, monitoring of optical output occupies an important position particularly in the field of wavelength multiplexing communication technology.

  In recent years, there is an increasing demand for downsizing, high performance, and low cost for such optical output monitoring technology.

  Conventionally, for example, a technique as shown in Patent Document 1 has been proposed. In this technique, as shown in FIG. 17, an optical fiber 202 is disposed in a V groove of a glass substrate 200, and then the optical fiber 202 is obliquely traversed (relative to its optical axis) with respect to the glass substrate 200. A slit 204 is formed in the substrate. Then, a light reflecting substrate (filter member) 206 is inserted into the slit 204, and an ultraviolet curable resin (adhesive) 208 is filled in the gap. The filter member 206 includes a substrate 210 and a multilayer film 212 formed on the main surface of the substrate 210. The multilayer film 212 is composed of the refractive index of the substrate 210 and the refraction of the resin 208 filled in the slit 204. Designed for rate.

  Thereby, out of the signal light 214 propagating through the optical fiber 202, the light component (reflected light) 216 reflected by the filter member 206 is taken out of the cladding. Therefore, the signal light 214 can be monitored by detecting the reflected light 216 with, for example, a light receiving element.

JP 2001-264594 A (FIGS. 1B and 2)

  In the prior art, the slit 204 is a parallel groove, and the inner wall surface of the slit 204, the main surface of the filter member 206 (the surface on the multilayer film 212 side), the surface of the substrate 210 of the filter member 206, and the slit 204. The inner wall surfaces are also set in parallel.

  Further, since the refractive index of the optical fiber 202 and the refractive index of the resin 208 are different, and the refractive index of the substrate 210 of the filter member 206 and the refractive index of the resin 208 are different, the first interface between the slit 204 and the resin 208 is used. 220, reflected light 226, 228 and 230 are also generated at the interface 222 between the substrate 210 and the resin 208 of the filter member 206 and the second interface 224 between the slit 204 and the resin 208.

  In general, the resin 208 filled in the slit 204 has a function of matching the refractive index, so that the refractive index difference between the optical fiber 202 and the resin 208 is small. Therefore, the output of the reflected light 226, 228, and 230 due to such a small refractive index difference is −several tens dB with respect to the input light (signal light 214). However, light causes interference because of its wave nature.

  Therefore, the reflected lights 226, 228, and 230 described above due to the difference in refractive index have a small power, but the emission direction thereof is substantially the same as the emission direction of the reflected light 216 on the multilayer film 212 of the filter member 206. It affects the characteristics of the light 216. Further, in the case of light splitting at the filter member 206 inserted into the slit 204 formed obliquely with respect to the optical axis direction, the characteristics of the reflected light 216 at the filter member 206 are the first and second characteristics described above. There is a problem that light 226, 228, and 230 reflected by the interfaces 220 and 224 and the like are likely to receive interference.

  The present invention has been made in consideration of such problems, and can reduce the influence of interference of light reflected by other portions with respect to the reflected light on the multilayer surface of the filter member. An object of the present invention is to provide an optical device capable of improving the reliability.

  An optical device according to the present invention includes: a light transmission means; a slit provided in the light transmission means; a filter member that is inserted into the slit and branches a part of signal light that propagates through the light transmission means; A resin filled in a gap between the slit and the filter member in the slit, the filter member including a substrate and an optical thin film formed on a main surface of the substrate, and the filter member A surface on the optical thin film side is defined as a first surface, a surface on the substrate side of the filter member is defined as a second surface, and a surface of the inner wall surface of the slit that faces the first surface of the filter member is defined as When the first inner wall surface and the surface facing the second surface of the filter member are defined as the second inner wall surface, the first inner wall surface of the slit, the second inner wall surface, and the filter member One or more surfaces of the second surface; Characterized in that a first face of the serial filter member is non-parallel.

  Of the first inner wall surface of the slit, the second inner wall surface, and the second surface of the filter member, the light reflected (branched) by a surface that is not parallel to the first surface of the filter member Since the emission direction is different from the emission direction of the reflected light (branched light) on the first surface of the filter member, it is possible to reduce the influence of interference on the reflected light on the first surface. This leads to an improvement in the reliability of the signal light monitoring function.

  Here, the optical thin film attached to the main surface of the filter member may be a single layer, but in many cases, an optical thin film optimally designed with a multilayer film is applied. Further, the main surface of the filter member may be disposed not only on the light incident side but also on the light exit side.

  The angle formed by the two non-parallel surfaces is preferably 0.5 ° or more. This is because if the angle is less than 0.5 °, the interference effect on the reflected light on the first surface cannot be reduced.

  And in the said structure, the 1st surface of the said filter member, the 2nd surface of the said filter member, the 1st inner wall surface of the said slit, the 2nd inner wall surface of the said slit, and the optical axis of the said signal light When the line segments formed by intersecting with the vertical plane are defined as the first line segment, the second line segment, the third line segment, and the fourth line segment, the second line segment, One or more of the third line segment and the fourth line segment may be non-parallel to the first line segment.

  Alternatively, the first line segment and the second line segment are non-parallel to each other, the third line segment and the fourth line segment are non-parallel to each other, and the first line segment and the The third line segments may be non-parallel to each other.

  Alternatively, the first line segment and the second line segment are parallel to each other, the third line segment and the fourth line segment are parallel to each other, and the first line segment and the third line segment are parallel to each other. These line segments may be non-parallel to each other.

  Alternatively, the first line segment and the second line segment are non-parallel to each other, the third line segment and the fourth line segment are parallel to each other, and the first line segment and the first line segment are The three line segments may be non-parallel to each other.

  Alternatively, the first line segment and the second line segment are parallel to each other, the third line segment and the fourth line segment are non-parallel to each other, and the first line segment and the first line segment are The three line segments may be non-parallel to each other.

  A first surface of the filter member; a second surface of the filter member; a first inner wall surface of the slit; a second inner wall surface of the slit; and a horizontal plane including an optical axis of the signal light. When the line segments formed to intersect with each other are defined as a fifth line segment, a sixth line segment, a seventh line segment, and an eighth line segment, the sixth line segment and the seventh line segment are defined. One or more of the minute and the eighth line segment and the fifth line segment may be non-parallel.

  Alternatively, the seventh line segment and the eighth line segment may be parallel to each other, and the fifth line segment and the seventh line segment may be non-parallel to each other.

  The optical device according to the present invention includes a plurality of light transmission means, a slit provided in common to the plurality of light transmission means, and inserted into the slit to propagate through the plurality of light transmission means. One filter member that branches each part of the signal light, and a resin filled in a gap between the slit and the filter member in the slit, the filter member facing at least the slit Is curved.

  Thereby, the surface facing the filter member of the slit and the surface facing the slit of the filter member are not parallel to each other across the plurality of light transmission means, and the front surface and the back surface of the filter member are not parallel to each other. Therefore, it is possible to reduce the influence of interference on the reflected light on the surface of the filter member. This leads to an improvement in the reliability of the signal light monitoring function.

  An optical device according to the present invention includes: a light transmission unit; a slit provided in the light transmission unit; a filter member that is inserted into the slit and branches a part of the signal light that propagates through the light transmission unit; A resin filled in a gap between the slit and the filter member in the slit, and the filter member includes a substrate and an optical thin film formed on a main surface of the substrate, and the filter member The optical thin film side surface of the filter member is defined as a first surface, and the substrate side surface of the filter member is defined as a second surface, and of the inner wall surface of the slit, the first surface of the filter member is opposed to the first surface. When the surface is defined as a first inner wall surface and the surface facing the second surface of the filter member is defined as a second inner wall surface, at least the second surface of the filter member is a rough surface. To do.

  Usually, the reflected light on the first surface of the filter member is strongly subject to interference due to the reflected light from the second surface of the filter member due to the thickness of the filter member and the like. However, in the present invention, since the second surface of the filter member is roughened, the reflected light from the second surface of the filter member is randomly emitted and becomes scattered light. Thus, the influence of interference on the reflected light on the surface is reduced.

  In the configuration, the first inner wall surface and the second inner wall surface of the slit may be rough surfaces. Thereby, the interference influence by the reflected light from the 1st inner wall surface and 2nd inner wall surface of a slit can be reduced effectively.

  The roughened surface preferably has a surface roughness Rt of 0.05 μm ≦ Rt ≦ 2 μm.

  In the above configuration, at least a part of the bottom surface of the filter member may be in contact with the bottom of the slit. In this case, the filter member can be maintained at a desired angle only by bringing a part of the bottom surface of the filter member into contact with the bottom of the slit, and the assembly is facilitated.

  As described above, according to the optical device according to the present invention, it is possible to reduce the interference effect of the light reflected by the other part with respect to the reflected light on the multilayer surface of the filter member, and the reliability of the signal light monitoring function. Can be improved.

  Hereinafter, an embodiment in which an optical device according to the present invention is applied to, for example, a 4ch in-line power monitor module will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the optical device 10 </ b> A according to the first embodiment includes a glass substrate 12 and a plurality of optical fibers 15 fixed to a plurality of V grooves 14 provided in the glass substrate 12. An optical fiber array 16, a slit 18 (see FIG. 2) provided from the upper surface of each optical fiber 15 to the glass substrate 12, and a branch member (filter member) 20 inserted into the slit 18 (FIG. 2). And a PD (photodiode) array in which a plurality of active layers 26 for detecting at least light (reflected light) 24 reflected by the filter member 20 or the like among signal light 22 transmitted through each optical fiber 15 is arranged. 28, the PD array 28 mounted thereon, a submount 30 for fixing the PD array 28 toward the optical fiber array 16, and at least the PD array 28 And a spacer 32 for fixing to a constant. The two end surfaces of the slit 18 and the front and back surfaces of the filter member 20 function as a branching portion 33 (see FIG. 2) that branches a part of the signal light 22 that passes through the optical fiber 15. The optical fiber 15 includes a core 40 and a clad 42 as shown in FIG.

  That is, the optical device 10A according to the first embodiment includes a glass substrate 12 having a V-groove 14 formed thereon, and is fixed to the V-groove 14 of the glass substrate 12 and has an optical branching function for each optical fiber 15. The optical fiber array 16 provided with the slits 18 and the filter members 20 and the like, and at least the optical path of the branched light 24 generated by the optical branching function out of the cladding of each optical fiber 15 is fixed via the adhesive layer 52. The PD array 28 and a submount 30 for mounting the PD array 28 are provided, and the submount 30 is installed so that the mounting surface of the PD array 28 faces the glass substrate 12.

  The angle of the V-groove 14 formed in the glass substrate 12 is preferably 45 ° or more in consideration of the load applied to each optical fiber 15 of the optical fiber array 16 when the slit 18 is processed later. Therefore, in order to ensure a sufficient amount of adhesive (= adhesive strength), it is preferably 95 ° or less, and in this first embodiment, it is set to 70 °.

  The optical fiber array 16 is fixed to the glass substrate 12 by first placing the optical fiber array 16 in the V-groove 14 and applying an ultraviolet curable adhesive in this state, from the back surface of the optical fiber array 16 and from above. It is carried out by irradiating ultraviolet rays to fully cure the adhesive.

  The inclination angle α of the slit 18 (see FIG. 2), that is, the angle formed with the vertical plane is preferably 15 ° to 25 °. If the inclination angle α is too small, the spread of the branched light 24 from the filter member 20 becomes too large, and when applied to multiple channels, crosstalk may be deteriorated. On the other hand, if the inclination angle α is too large, the polarization dependency of the branched light 24 from the filter member 20 increases, which may lead to deterioration of characteristics.

  As shown in FIG. 3, the filter member 20 includes a quartz substrate 54 and a branching multilayer film 56 formed on the main surface of the quartz substrate 54. The material of the filter member 20 may be a plastic material, a polymer material, or a polyimide material in consideration of the handling of the filter member 20, but the inclination angle α of the slit 18 is as large as 15 ° to 25 °. A material having the same refractive index as that of the optical fiber 15 (quartz) is preferable in order to prevent the transmission side optical axis from deviating.

  Further, an ultraviolet curable resin (adhesive) 19 is filled in a gap between the slit 18 and the filter member 20 in the slit 18. The resin 19 is made of silicone resin so that the refractive index thereof is substantially the same as the refractive index of the core 40 of the optical fiber 15 and the refractive index of the quartz substrate 54 of the filter member 20.

  The structure of the PD array 28 is a back-illuminated type as shown in FIG. The upper part (on the submount 30 side) of the active layer 26 is not an Au solder, an electrode, or a silver paste but an anisotropic conductive paste 58. It is preferable from the viewpoint of crosstalk that this portion is not a material with high reflectivity such as Au, but is in a low reflectivity state such as anisotropic conductive paste 58 or air. Of course, a front-illuminated PD array may be used as the PD array 28.

  The light receiving portion (active layer 26) of the back-illuminated PD array 28 was set to about 60 μm. The size of the light receiving portion (active layer 26) is preferably φ40 to 80 μm. If the thickness is less than 40 μm, the size of the light receiving portion (active layer 26) is too small, and there is a concern that the PD light receiving efficiency may decrease. This is because when the thickness is 80 μm or more, stray light is easily picked up, and the crosstalk characteristics may be deteriorated.

Further, the mounting structure of the submount 30 employs a configuration of an optical fiber 15 -PD array 28 -submount 30. Although the configuration of the optical fiber 15-submount 30-PD array 28 is also possible, in this case, since the submount 30 exists between the optical fiber 15 and the PD array 28, the optical path length of the branched light 24 becomes long, This is because the spread of the branched light 24 becomes large, which is not preferable from the viewpoint of PD light receiving efficiency and crosstalk. The constituent material of the submount 30 was Al ₂ O ₃ .

  In the back-illuminated PD array 28, an anode electrode and a cathode electrode are disposed on the active layer 26 side (submount 30 side). The common cathode electrode and the anode electrode of each channel are Au electrode patterns on the submount 30. Patterned at 60. Au bumps 62 were provided in portions corresponding to the anode electrode and the cathode electrode of each channel, and the portion of the active layer 26 was filled with an anisotropic conductive paste 58. In addition to the purpose of ensuring reliable conduction, the Au bump 62 employs this structure for the purpose of reducing stray light due to reflection / scattering of this portion by increasing the distance between the electrodes of the active layer 26 and the submount 30. The anisotropic conductive paste 58 has such a property that when heat is applied, a conductive material such as silver in the anisotropic conductive paste 58 gathers in a conductive material such as the Au bump 62. As a result, electrical conductivity is provided only between the Au electrode pattern 60.

  Note that, on the lower surface of the submount 30, the portion corresponding to the active layer 26 was also coated with SiN (not shown) for the purpose of suppressing reflection due to the difference in refractive index.

  Further, a spacer 32 for determining a gap between the optical fiber array 16 and the PD array 28 is fixed to the mounting surface of the submount 30 with, for example, an ultraviolet curable adhesive.

  In the optical device 10A according to the first embodiment, as shown in FIG. 3, the surface of the filter member 20 on the multilayer film 56 side is the first surface 70, and the surface of the filter member 20 on the quartz substrate 54 side. Of the inner surface of the slit 18, the surface facing the first surface 70 of the filter member 20 is the surface facing the first inner wall surface 74 and the second surface 72 of the filter member 20. Is defined as the second inner wall surface 76, one or more of the first inner wall surface 74, the second inner wall surface 76 of the slit 18, and the second surface 72 of the filter member 20, and the filter member 20 first surfaces 70 are not parallel to each other. Here, the term “non-parallel” means that the angle formed by the two non-parallel surfaces is 0.5 ° or more.

  Specifically, in the first embodiment, a line segment formed by intersecting the first surface 70 of the filter member 20 and the vertical surface including the optical axis of the signal light 22 is defined as the first line. A second line segment 82 formed by intersecting the second surface 72 of the filter member 20 and the vertical surface, and a first inner wall surface 74 of the slit 18 intersecting the vertical surface. When the line segment formed is defined as a third line segment 84 and the line segment formed by intersecting the second inner wall surface 76 of the slit 18 and the vertical plane is defined as a fourth line segment 86, The first line segment 80 and the second line segment 82 are non-parallel to each other, the third line segment 84 and the fourth line segment 86 are non-parallel to each other, and the first line segment 80 and the third line segment 82 are The line segment 84 is not parallel to each other. The magnitude relationship between the inclination angle α of the slit 18 and the inclination angle (angle formed with the vertical line) β of the first line segment 80 is α <β. The PD array 28 (see FIG. 2) is placed on the optical path of the light 24 reflected from the surface (first surface 70) of the multilayer film 56 of the filter member 20.

  As a result, the light 90 reflected by the first inner wall surface 74 portion of the slit 18 (the interface between the first inner wall surface 74 side of the slit 18 and the resin 19) and the second inner wall surface 76 portion of the slit 18. The light 92 reflected by (the interface between the second inner wall surface 76 side of the slit 18 and the resin 19) and the portion of the second surface 72 of the filter member 20 (the interface between the quartz substrate 54 and the resin 19) are reflected. Since each emission direction of the light 94 is different from the emission direction of the light 24 reflected by the portion of the first surface 70 of the filter member 20 (the interface between the multilayer film 56 of the filter member 20 and the resin 19), the reflection is performed. Interference effects caused by other reflected lights 90, 92, and 94 on the light (branched light) 24 can be reduced. This leads to an improvement in the reliability of the monitoring function of the signal light 22.

  Next, some modified examples related to the optical device 10A according to the first embodiment will be described with reference to FIGS.

  First, as shown in FIG. 4, the optical device 10 </ b> Aa according to the first modification has substantially the same configuration as the optical device 10 </ b> A according to the first embodiment described above, but the first of the filter member 20. The line segment 80 and the second line segment 82 of the filter member 20 are parallel to each other, and the third line segment 84 of the slit 18 and the fourth line segment 86 of the slit 18 are parallel to each other. The difference is that one line segment 80 and the third line segment 84 of the slit 18 are non-parallel to each other.

  As shown in FIG. 5, the optical device 10Ab according to the second modified example has substantially the same configuration as the optical device 10Aa according to the first modified example described above, but the inclination angle α of the slit 18 and the first The difference is that the magnitude relationship between the line segment 80 and the inclination angle β is α> β.

  As shown in FIG. 6, the optical device 10Ac according to the third modification has substantially the same configuration as the optical device 10 </ b> Aa according to the first modification described above, but the first line segment 80 of the filter member 20. And the second line segment 82 of the filter member 20 is different from each other in that they are not parallel to each other.

  As shown in FIG. 7, the optical device 10Ad according to the fourth modification has substantially the same configuration as the optical device 10Aa according to the first modification described above, but the third line segment 84 of the slit 18 and The difference is that the fourth line segment 86 of the slit 18 is not parallel to each other.

  As shown in FIG. 8, the optical device 10Ae according to the fifth modification has substantially the same configuration as the optical device 10Ac according to the third modification described above, but differs in the following points.

  That is, the magnitude relationship between the inclination angle α of the slit 18 and the inclination angle β of the first line segment 80 is α> β. Further, the difference is that the bottom surface 20 a of the filter member 20 is in contact with the bottom portion 18 a of the slit 18. In this case, the filter member 20 can be maintained at a desired angle β by simply bringing the bottom surface 20a of the filter member 20 into contact with the bottom portion 18a of the slit 18, and the assembling work is facilitated.

  As shown in FIG. 9, the optical device 10Af according to the sixth modification has substantially the same configuration as the optical device 10Ae according to the fifth modification described above, but the first line segment 80 of the filter member 20 is used. The second line segment 82 and the fourth line segment 86 of the slit 18 are different from each other in that the bottom surface 20a of the filter member 20 is in contact with the bottom 18a of the slit 18.

  As shown in FIG. 10, the optical device 10Ag according to the seventh modification has substantially the same configuration as the optical device 10Ab according to the second modification described above, but differs in the following points.

  First, of the second line segment 82 of the filter member 20, the angle of a line segment that does not reach the portion corresponding to the core 40 of the optical fiber 15 from the bottom surface 20 a (referred to as a lower part 82 a of the second line segment 82) and Of the second line segment 82, the angle of the line segment (referred to as the upper part 82b of the second line segment 82) including the part corresponding to the core 40 of the optical fiber 15 is different. That is, the second surface 72 of the filter member 20 is bent halfway.

  Further, the third line segment 84 and the fourth line segment 86 of the slit 18 are parallel to each other. The angle of the lower portion 82 a of the second line segment 82 of the filter member 20 is substantially the same as the angle of the fourth line segment 86 of the slit 18. The upper portion 82b of the second line segment 82 of the filter member 20 and the first line segment 80 of the filter member 20 are parallel to each other. The bottom surface 20 a of the filter member 20 is in contact with the bottom portion 18 a of the slit 18.

  That is, this optical device 10Ag has a bent surface formed by the bottom 18a of the slit 18 and the second inner wall surface 76, and a lower surface 72a (second surface) of the bottom surface 20a of the filter member 20 and the second surface 72. A bent surface formed by a surface corresponding to the lower portion 82a of the line segment 82 is in contact with the bent portion 82a.

  Therefore, when the filter member 20 is inserted into the slit 18 during assembly, the filter member 20 can be easily placed in the slit 18 simply by aligning the bent surface of the filter member 20 with the bent surface of the slit 18. It can be temporarily fixed at an angle, and the subsequent assembly work becomes easy.

  Next, as shown in FIG. 11, the optical device 10Ah according to the eighth modification has substantially the same configuration as the optical device 10Ag according to the seventh modification described above, but differs in the following points.

  First, the first line segment 80 and the second line segment 82 of the filter member 20 are parallel to each other. The bottom surface 20 a of the filter member 20 is in contact with the bottom portion 18 a of the slit 18. Further, the lower end portion of the first surface 70 of the filter member 20 is in contact with the lower end portion of the first inner wall surface 74 of the slit 18, and the upper end portion of the second surface 72 of the filter member 20 is the first end of the slit 18. 2 is in contact with the upper end of the inner wall surface 76.

  Also in this case, similarly to the optical device 10Ag according to the seventh modification described above, the filter member 20 is inserted into the slit 18 during assembly, and the bottom surface 20a of the filter member 20 is connected to the bottom portion 18a of the slit 18. At the stage of contact, the filter member 20 can be simply temporarily fixed in the slit 18 at a desired angle, and subsequent assembly work is facilitated.

  Next, as shown in FIG. 12, the optical device 10Ai according to the ninth modification has substantially the same configuration as the optical device 10Af according to the sixth modification described above, but differs in the following points.

  Of the third line segment of the slit 18, the angle of the line segment (referred to as the lower portion 84 a of the third line segment 84) that does not reach the portion corresponding to the core 40 of the optical fiber 15 from the bottom 18 a, and the third The angle of the line segment including the portion corresponding to the core 40 of the optical fiber 15 (referred to as the upper portion 84b of the third line segment 84) is different. That is, the first inner wall surface 74 of the filter member 20 is bent halfway.

  This is because the first and second surfaces 70 and 72 of the filter member 20 and the first inner wall surface 74 and the second inner wall surface 76 of the slit 18 are substantially parallel. In a certain structure, the optical device 10Ai according to the ninth modification can be made by merely making a cut from the top with respect to the first inner wall surface 74 of the slit 18. This can be made easier than the case where the optical devices 10Aa to 10Ah according to the first to eighth modifications are made, and the angle difference between the slit 18 and the filter member 20 can be freely changed. . Of course, it is possible to quickly respond to specification changes and the like.

  In the optical devices 10Aa to 10Ai according to the first to ninth modifications, the reflection from the portion of the first surface 70 of the filter member 20 is similar to the optical device 10A according to the first embodiment described above. The influence of interference due to the other reflected lights 90, 92, 94 and the like on the light 24 can be reduced, and the reliability of the monitoring function of the signal light 22 can be improved.

  Next, an optical device 10B according to a second embodiment will be described with reference to FIG.

  In the optical device 10B according to the second embodiment, as shown in FIG. 13, a line formed by intersecting the first surface 70 of the filter member 20 and the horizontal plane including the optical axis of the signal light 22. The fifth line segment 100, the second line 72 of the filter member 20 and the horizontal plane intersect with each other, the line segment formed by the sixth line segment 102, the first inner wall surface 74 of the slit 18 and the above-mentioned line segment. A line segment formed by intersecting the horizontal plane is defined as a seventh line segment 104, and a line segment formed by intersecting the second inner wall surface 76 of the slit 18 and the horizontal plane is defined as an eighth line segment 106. In this case, the seventh line segment 104 and the eighth line segment 106 are parallel to each other, and the fifth line segment 100 and the seventh line segment 104 are not parallel to each other.

  Also in this case, similarly to the optical device 10A according to the first embodiment described above, the other reflected lights 90 and 92 with respect to the reflected light 24 (see FIG. 2) from the portion of the first surface 70 of the filter member 20. And 94 and the like can be reduced, and the reliability of the monitoring function of the signal light 22 can be improved.

  In the second embodiment, it is sufficient that the fifth line segment 100 and the seventh line segment 104 are not parallel to each other, and the relationship between the other line segments is not limited. For example, the fifth line segment 100 and the sixth line segment 102 may be parallel or non-parallel to each other, and the fifth line segment 100 and the eighth line segment 106 may be parallel or non-parallel to each other. Also good. Similarly, the sixth line segment 102 and the seventh line segment 104 may be parallel or non-parallel to each other, and the sixth line segment 102 and the eighth line segment 106 may be parallel or non-parallel to each other. There may be.

  Next, an optical device 10C according to a third embodiment will be described with reference to FIG.

  As shown in FIG. 14, the optical device 10C according to the third embodiment has substantially the same configuration as the optical device 10A according to the first embodiment described above. In particular, for example, one slit 18 is provided in common to the optical fiber array 16 including seven optical fibers 15, and one filter member 20 is inserted into the slit 18, and the slit 18 in the slit 18 A resin 19 is filled in a gap with the filter member 20.

  In the filter member 20, at least a surface (first surface) 70 facing the first inner wall surface 74 of the slit 18 is curved in a concave shape toward the first inner wall surface 74. The degree of bending is preferably such that the difference between the central portion and both end portions of the filter member 20 is not less than 5 μm and not more than 100 μm. This is because if it is less than 5 μm, it is difficult to provide a desired angle difference, and if it exceeds 100 μm, it is difficult to insert the filter member 20.

  Thus, in the optical device 10 </ b> C according to the third embodiment, the surface (first inner wall surface) 74 of the slit 18 facing the filter member 20 and the slit of the filter member 20 over the seven optical fibers 15. 18 (first surface) 70 facing the first inner wall surface 74 is not parallel to each other, and the first surface 70 and the second surface 72 of the filter member 20 are not parallel to each other. . Therefore, it is possible to reduce the influence of interference by other reflected light 90, 92, 94, etc. on the reflected light 24 on the surface of the multilayer film 56 of the filter member 20, and to improve the reliability of the monitoring function of the signal light 22. Can do.

  The method of bending the filter member 20 can be easily set by the configuration of the multilayer film 56 formed on the surface of the quartz substrate 54, for example. That is, by forming the multilayer film 56, stress acts on the quartz substrate 54, and the quartz substrate 54 curves in a concave shape on the surface on which the multilayer film 56 is formed. The degree of bending can be appropriately adjusted according to the material and thickness of each film constituting the multilayer film 56, the number of layers of the multilayer film 56, and the like.

  As another method, a method of bending the quartz substrate 54 by changing the finishing accuracy (for example, the degree of polishing) of the front surface and the back surface of the quartz substrate 54 is also preferably employed. Of the quartz substrate 54, the finishing accuracy of the surface on which the multilayer film 56 is to be formed may be increased (for example, ▽▽▽ by a finishing symbol), and the finishing precision of the back surface may be lowered (for example, ▽ by a finishing symbol).

  As another method, it is preferable to apply a method in which air is applied to the front and back surfaces of the quartz substrate 54 and the air volume is changed between the front and back surfaces when the quartz substrate 54 is purified. Is done. By making the air volume with respect to the surface of the quartz substrate 54 larger than the air volume with respect to the back surface, the compressive stress generated on the surface of the quartz substrate 54 at the time of refining becomes higher than the compressive stress generated on the back surface. A quartz substrate 54 whose surface (surface on which the multilayer film 56 is formed) is curved in a concave shape can be manufactured.

  Next, an optical device 10D according to a fourth embodiment will be described with reference to FIG.

  As shown in FIG. 15, the optical device 10D according to the fourth embodiment has substantially the same configuration as the optical device 10A according to the first embodiment described above. The point where the surface 70, the first inner wall surface 74 of the slit 18 and the second inner wall surface 76 of the slit 18 are parallel to each other, and the second surface 72 (the back surface of the quartz substrate 54) of the filter member 20 are It differs in that it has a rough surface.

  Of course, the first surface 70 of the filter member 20 and the first inner wall surface 74 of the slit 18 may be non-parallel to each other.

  Usually, the reflected light from the first surface 70 of the filter member 20 (the surface of the multilayer film 56) is strongly affected by the reflected light from the second surface 72 of the filter member 20 depending on the thickness of the filter member 20 and the like. It will be. The interference caused by the reflected light from the first inner wall surface 74 of the slit 18 and the reflected light from the second inner wall surface 76 of the slit 18 is caused by the interference caused by the reflected light from the second surface 72. Is also small.

  In this 3rd Embodiment, since the 2nd surface 72 of the filter member 20 is made into the rough surface, the reflected light from the 2nd surface 72 of the filter member 20 radiate | emits at random, and becomes a scattered light. For this reason, the interference effect of the reflected light from the second surface 72 on the reflected light from the first surface 70 of the filter member 20 is effectively reduced, and the reliability of the monitoring function of the signal light 22 is efficiently improved. Can be improved.

  As a method for making the back surface of the quartz substrate 54 rough, for example, there is a method of grinding with a rough grindstone when processing the quartz substrate 54. More preferably, a method of etching with a chemical such as hydrofluoric acid is employed. Further, a method of changing the surface state by melting the laser processing fiber, or a method of changing the shape only in the vicinity of the core by the laser may be used.

  Further, when the quartz substrate 54 is manufactured by spin coating, the irregularities can be transferred to the back surface of the quartz substrate 54 by providing irregularities on the surface of the spin coater.

  When the quartz substrate 54 is manufactured by a glass press, a portion of the mold that forms the back surface of the quartz substrate 54 is roughened in advance, so that the rough surface of the mold is placed on the back surface of the quartz substrate 54 at the end of pressing. The surface will be transferred.

  In the optical device 10D according to the above-described fourth embodiment, only the second surface 72 of the filter member 20 is roughened, but in addition, as in the optical device 10Da according to the modification shown in FIG. The 18 first inner wall surface 74 and the second inner wall surface 76 may be both roughened. In this case, the reflected light from the portion of the first inner wall surface 74 of the slit 18 and the reflected light from the portion of the second inner wall surface 76 of the slit 18 are also scattered light, so the first surface of the filter member 20 The influence of interference on the reflected light from the portion 70 can be further reduced.

  In the optical devices 10A to 10D according to the first to fourth embodiments described above, the example is applied to the optical fiber array 16 in which the plurality of optical fibers 15 are arranged. The present invention can also be applied to an optical waveguide array having a plurality of optical waveguides formed.

  An example of the optical device 10A according to the first embodiment will be described. First, the glass substrate 12 used for the in-line optical fiber array 16 was produced by grinding.

  As the material of the glass substrate 12, borosilicate glass (here, in particular, Pyrex (registered trademark) glass material) was used. The glass substrate 12 had a length of 16 mm and a thickness of 1 mm. The V-grooves 14 for aligning the optical fiber array 16 were formed by grinding 12 pieces at a pitch of 250 μm and a depth of about 90 μm.

  Next, the optical fiber array 16 was assembled. The optical fiber array 16 was a 12-core tape core wire with a pitch of 250 μm. The 12-core tape core wire was peeled in the middle so that the coating removal portion (striped portion) was 12 mm, placed on the V groove 14 of the glass substrate 12, and fixed with an ultraviolet curable adhesive.

  Next, the slit 18 for the optical fiber array 16 was processed. The slit 18 had a width of 30 μm, a depth of 200 μm, and an inclination angle α of 20 °.

  Next, the filter member 20 was manufactured. For example, a multilayer film 56 arbitrarily selected from tantalum oxide, quartz, alumina, titanium oxide or the like is formed on the quartz substrate 54 by vapor deposition, and the quartz substrate 54 on which the multilayer film 56 is formed has a thickness of 20 μm, a length of 5 mm, and a width. The filter member 20 was fabricated by processing into a 200 μm shape. The inclination design was 20 °, the branching ratio was 93% transmission, and 7% reflection.

  Thereafter, the filter member 20 is inserted into the slit 18, and further on the positioning stage so that the first surface 70 of the filter member 20 has an inclination angle β of, for example, 20.5 ° to 21 ° with respect to the optical axis. It was adjusted. The filter member 20 was inserted into the slit 18 and the resin 19 was filled into the slit 18 in a state where the filter member 20 was fixed at the inclination angle β. As the resin 19, a silicone-based resin was used so that the refractive index was substantially the same as the refractive index of the core 40 of the optical fiber 15. After the resin 19 was filled, the resin 19 was cured.

  Thereafter, the PD array 28 was mounted on the submount 30. The number of channels of the PD array 28 was 12 ch, and the dimensions were 150 μm high, 420 μm wide, and 3 mm long.

  As the structure of the PD array 28, a back-illuminated type is employed, as in the optical device 10A according to the first embodiment. The upper part of the active layer 26 (submount 30 side) was filled with an anisotropic conductive paste 58.

  Next, alignment of the PD array 28 was performed. Specifically, a spacer 32 for determining a gap between the optical fiber array 16 and the PD array 28 is attached to the submount 30.

  The constituent material of the spacer 32 is borosilicate glass, in this case, in particular, Pyrex (registered trademark) glass material. The gap length was set to 10 μm. That is, since the thickness of the PD array 28 including the Au bumps 62 is 190 μm, the spacer 32 is set to 200 μm.

  Then, while aligning the PD array 28 so that the active layer 26 of the PD array 28 is positioned on the optical path of the reflected light 24 from the first surface 70 of the filter member 20, the submount 30 is placed on the optical fiber array 16. It was mounted via a spacer 32 on the top.

  And the measurement evaluation of the optical device which concerns on an Example was implemented. The influence of the reflected light due to the difference in refractive index appears remarkably due to the characteristic variation of the light receiving efficiency in the PD array 28 due to the temperature change and the characteristic variation of the light receiving efficiency in the PD array 28 after the high temperature and high humidity test. Therefore, paying attention to these two points, the evaluation was performed together with the comparative example.

  The comparative example has a configuration in which the difference between the inclination angle α of the slit 18 and the inclination angle β of the first surface 70 of the filter member 20 is set to less than 0.5 in the optical device 10A according to the first embodiment. Have.

  In the comparative example, the fluctuation of the light receiving efficiency due to the temperature change was about 0.5 dB. In addition, the fluctuation in light receiving efficiency after the high temperature and high humidity test was about 0.5 dB.

  On the other hand, in the optical device according to the example, both of the fluctuation of the light receiving efficiency due to the temperature change and the fluctuation of the light receiving efficiency after the high temperature and high humidity test are about 0.1 dB, and it was found that the characteristic variation is hardly seen.

  The optical device according to the present invention is not limited to the above-described embodiment, but can of course have various configurations without departing from the gist of the present invention.

It is sectional drawing which shows the optical device which concerns on 1st Embodiment seeing from the front. It is sectional drawing which shows the optical device which concerns on 1st Embodiment seeing from a side surface. It is sectional drawing which expands and shows the principal part of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 1st modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 2nd modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 3rd modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 4th modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 5th modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 6th modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 7th modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 8th modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the 9th modification of the optical device which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the optical device which concerns on 2nd Embodiment. It is sectional drawing which expands and shows the principal part of the optical device which concerns on 3rd Embodiment. It is sectional drawing which expands and shows the principal part of the optical device which concerns on 4th Embodiment. It is sectional drawing which expands and shows the principal part of the modification of the optical device which concerns on 4th Embodiment. It is sectional drawing which expands and shows the principal part of the optical device which concerns on a prior art example.

Explanation of symbols

10A, 10Aa to 10Ai, 10B, 10C, 10D, 10Da ... Optical device 15 ... Optical fiber 16 ... Optical fiber array 18 ... Slit 19 ... Resin 20 ... Filter member 22 ... Signal light 24 ... Reflected light (branched light) 33 ... Reflected Part (branch part)
DESCRIPTION OF SYMBOLS 40 ... Core 42 ... Cladding 56 ... Multilayer film 70 ... 1st surface 72 ... 2nd surface 74 ... 1st inner wall surface 76 ... 2nd inner wall surface 80 ... 1st line segment 82 ... 2nd line segment 84 ... Third line segment 86 ... Fourth line segment 100 ... Fifth line segment 102 ... Sixth line segment 104 ... Seventh line segment 106 ... Eighth line segment

Claims (14)

Light transmission means;
A slit provided in the light transmission means;
A filter member that is inserted into the slit and branches a part of the signal light propagating through the light transmission means;
Having a resin filled in a gap between the slit and the filter member in the slit,
The filter member has a substrate and an optical thin film formed on the main surface of the substrate,
The surface on the optical thin film side of the filter member is defined as a first surface, the surface on the substrate side of the filter member is defined as a second surface, and the first surface of the filter member among the inner wall surfaces of the slit. When the surface facing the first inner wall surface and the surface facing the second surface of the filter member are defined as the second inner wall surface,
One or more surfaces of the first inner wall surface, the second inner wall surface, and the second surface of the filter member of the slit and the first surface of the filter member are non-parallel. Features optical device. The optical device according to claim 1.
2. An optical device characterized in that an angle formed by the two non-parallel surfaces is 0.5 ° or more. The optical device according to claim 1.
The first surface of the filter member, the second surface of the filter member, the first inner wall surface of the slit and the second inner wall surface of the slit intersect with a vertical surface including the optical axis of the signal light. And defining each of the formed line segments as a first line segment, a second line segment, a third line segment, and a fourth line segment,
One or more of the second line segment, the third line segment, and the fourth line segment, and the first line segment are non-parallel. The optical device according to claim 3.
The first line segment and the second line segment are non-parallel to each other;
The third line segment and the fourth line segment are non-parallel to each other;
The optical device, wherein the first line segment and the third line segment are non-parallel to each other. The optical device according to claim 3.
The first line segment and the second line segment are parallel to each other;
The third line segment and the fourth line segment are parallel to each other;
The optical device, wherein the first line segment and the third line segment are non-parallel to each other. The optical device according to claim 3.
The first line segment and the second line segment are non-parallel to each other;
The third line segment and the fourth line segment are parallel to each other;
The optical device, wherein the first line segment and the third line segment are non-parallel to each other. The optical device according to claim 3.
The first line segment and the second line segment are parallel to each other;
The third line segment and the fourth line segment are non-parallel to each other;
The optical device, wherein the first line segment and the third line segment are non-parallel to each other. The optical device according to claim 1.
The first surface of the filter member, the second surface of the filter member, the first inner wall surface of the slit and the second inner wall surface of the slit intersect with a horizontal plane including the optical axis of the signal light. Are defined as a fifth line segment, a sixth line segment, a seventh line segment, and an eighth line segment,
One or more of the sixth line segment, the seventh line segment, and the eighth line segment, and the fifth line segment are non-parallel. The optical device according to claim 8.
The seventh line segment and the eighth line segment are parallel to each other;
The optical device, wherein the fifth line segment and the seventh line segment are non-parallel to each other. A plurality of light transmission means;
A slit provided in common for the plurality of light transmission means;
One filter member that is inserted into the slit and branches each part of the signal light propagating through the plurality of light transmission means;
Having a resin filled in a gap between the slit and the filter member in the slit,
An optical device, wherein the filter member has a curved surface at least facing the slit. Light transmission means;
A slit provided in the light transmission means;
A filter member that is inserted into the slit and branches a part of the signal light propagating through the light transmission means;
Having a resin filled in a gap between the slit and the filter member in the slit,
The filter member has a substrate and an optical thin film formed on the main surface of the substrate,
The surface on the optical thin film side of the filter member is defined as a first surface, the surface on the substrate side of the filter member is defined as a second surface, and among the inner wall surfaces of the slit, the first surface of the filter member When the surface facing the first inner wall surface and the surface facing the second surface of the filter member are defined as the second inner wall surface,
An optical device, wherein at least the second surface of the filter member is a rough surface. The optical device according to claim 11.
The optical device according to claim 1, wherein the first inner wall surface and the second inner wall surface of the slit are rough surfaces. The optical device according to claim 11 or 12,
The roughened surface has a surface roughness Rt of
0.05μm ≦ Rt ≦ 2μm
An optical device characterized by being. The optical device according to any one of claims 1 to 13,
At least a part of the bottom surface of the filter member is in contact with the bottom of the slit.

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