JP2014035474A - Array waveguide diffraction grating type optical multiplexer/demultiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an array waveguide diffraction grating type optical multiplexer/demultiplexer which has good temperature dependence of optical characteristics.SOLUTION: The array waveguide diffraction grating type optical multiplexer/demultiplexer includes: an AWG chip which includes a first slab waveguide connected to a first input/output waveguide, an array waveguide comprising a plurality of channel waveguides connected to the first slab waveguide, a second slab waveguide connected to the array waveguide, and a plurality of second input/output waveguides connected to the second slab waveguide and is cut into two by a cut surface traversing the first or second slab waveguide; an underlying plate which is joined to a lower surface of the AWG chip and is cut in at least one part along the cut surface of the AWG chip; a compensation member which is provided like a bridge between areas of the underlying plate separated from each other by the cut surface and compensates for a temperature-dependent shift of a light transmission center wavelength of the AWG; and a warpage reduction member which has a linear expansion coefficient equal to or higher than that of the underlying plate and lower than that of the compensation member and is bonded to the compensation member via an adhesive so as to reduce stress between the underlying plate and the compensation member.

Description

  The present invention relates to an arrayed waveguide grating optical multiplexer / demultiplexer.

  A wavelength multiplexer / demultiplexer using an arrayed waveguide grating (AWG) has a temperature dependency on the refractive index of the silica-based glass, which is a constituent material, so that the transmission center wavelength has a temperature dependency. It has been known.

  The temperature dependence dλ / dT of the transmission center wavelength of an AWG made of quartz glass is 0.011 nm / ° C., which is a large size that cannot be ignored for use in a D-WDM (Dense-Wavelength Division Multiplexing) optical transmission system. It is a value.

  In order to eliminate the temperature dependence, there is a technique for controlling the temperature of the AWG to be constant by a heating element or a cooling element using electric power. However, in D-WDM optical transmission systems that have been diversified in recent years, there is a strong demand for AWGs that do not require electric power (temperature independence).

  Patent Documents 1 and 2 disclose an arrayed waveguide grating optical multiplexer / demultiplexer (hereinafter, referred to as an AWG optical multiplexer / demultiplexer as appropriate) that realizes athermalization using a compensation member. The AWG type optical multiplexer / demultiplexer of Patent Documents 1 and 2 includes a compensation member having a predetermined thermal expansion coefficient so that the AWG chip is cut so as to cross the slab waveguide, and the parts separated by the cutting are spanned. The configuration is provided. When the temperature of the AWG type optical multiplexer / demultiplexer changes, the compensation member expands and contracts to change the relative position between the separated portions. The change amount of the relative position is adjusted so as to compensate for the shift of the transmission center wavelength depending on the temperature change. As a result, the athermalization of the AWG type optical multiplexer / demultiplexer is realized.

Japanese Patent No. 3764105 JP 2009-237205 A

  However, when an AWG type optical multiplexer / demultiplexer is manufactured, the temperature dependence characteristics of optical characteristics such as the transmission wavelength and insertion loss vary among a plurality of AWG type optical multiplexers / demultiplexers. In some cases, the temperature characteristics are not good due to the occurrence of hysteresis in the optical characteristics with respect to temperature fluctuations.

  The present invention has been made in view of the above, and an object of the present invention is to provide an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer having excellent temperature-dependent optical characteristics.

  In order to solve the above-described problems and achieve the object, an arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention includes a first input / output waveguide through which light is input / output and the first input / output waveguide. A first slab waveguide connected to the waveguide, an array waveguide connected to the first slab waveguide, and having a plurality of channel waveguides of different lengths arranged in parallel, and connected to the array waveguide A second slab waveguide formed and a plurality of second input / output waveguides connected to the second slab waveguide through which light is input and output, and the first slab waveguide or the second slab waveguide An arrayed waveguide grating chip cut into two at a cutting plane crossing the slab waveguide, and bonded to the lower surface of the arrayed waveguide grating chip, and at least along the cutting surface of the arrayed waveguide grating chip With the base plate cut in part Relative relation between each of the cut arrayed waveguide grating chips fixed by an adhesive so as to be stretched over a region of the base plate separated by the cut surface, and expanded and contracted according to a temperature change. By changing the position, a compensation member that compensates for a temperature-dependent shift of the light transmission center wavelength of the arrayed waveguide grating, and a linear expansion coefficient that is greater than or equal to the linear expansion coefficient of the base plate and less than the linear expansion coefficient of the compensation member. And a warp mitigating member bonded to the compensating member via an adhesive so as to relieve stress generated between the base plate and the compensating member.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is characterized in that, in the above invention, the warp mitigating member is provided so as to be interposed between the base plate and the compensating member. And

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is the above-described invention, wherein the warp mitigating member is provided such that the compensation member is interposed between the warp mitigating member and the base plate. It is characterized by.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is the above-described invention, wherein an adhesive surface between the warp mitigating member and the base plate and an adhesive surface between the warp mitigating member and the compensation member are substantially parallel. It is characterized by being.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is the above invention, wherein an adhesive surface between the warp mitigating member and the base plate and an adhesive surface between the warp mitigating member and the compensation member are non-parallel. It is characterized by being.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is characterized in that, in the above invention, the warp mitigating member is made of a material that transmits ultraviolet rays.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is characterized in that, in the above invention, the warp mitigating member and the base plate have the same linear expansion coefficient.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is the above-described invention, wherein the arrayed waveguide grating chip and the base plate are the first slab waveguide or the second slab waveguide. A fixed piece and a movable piece are cut at the cutting plane crossing the line to form a fixed piece and a movable piece, and the compensation member is provided to be spanned between the fixed piece and the movable piece. Features.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is the above-described invention, wherein the fixed piece is joined and the movable piece abuts on the reference plate, and the movable piece is on the reference plate. And a clip for sandwiching the reference plate and the movable piece so as to be slidable.

  The arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is characterized in that, in the above invention, the arrayed waveguide grating chip has a shape along the contour of the arrayed waveguide grating. To do.

  According to the present invention, it is possible to realize an arrayed waveguide grating type optical multiplexer / demultiplexer having excellent temperature-dependent optical characteristics.

FIG. 1 is a schematic top view of an AWG type optical multiplexer / demultiplexer according to the first embodiment. FIG. 2 is a rear view of the AWG type optical multiplexer / demultiplexer shown in FIG. 3 is a cross-sectional view of the AWG type optical multiplexer / demultiplexer shown in FIG. 4 is a cross-sectional view taken along line YY of the AWG type optical multiplexer / demultiplexer shown in FIG. FIG. 5 is a diagram illustrating a case where a step is generated between two base plate pieces. FIG. 6 is a diagram for explaining a manufacturing process of the AWG type optical multiplexer / demultiplexer shown in FIG. FIG. 7 is a diagram for explaining a manufacturing process of the AWG type optical multiplexer / demultiplexer shown in FIG. FIG. 8 is a diagram illustrating circuit parameters of the AWG type optical multiplexer / demultiplexer according to the first embodiment and the first comparative example. FIG. 9 is a diagram showing the measurement points of the step. FIG. 10 is a diagram showing the temperature dependence of the transmission center wavelength and insertion loss variation of the AWG type optical multiplexer / demultiplexer according to the first embodiment. FIG. 11 is a diagram showing the temperature dependence of the variation of the transmission center wavelength and the insertion loss for a certain sample of the AWG type optical multiplexer / demultiplexer of Comparative Example 1. FIG. 12 is a schematic top view of the AWG type optical multiplexer / demultiplexer according to the second embodiment. FIG. 13 is a diagram illustrating the temperature dependence of the variation of the transmission center wavelength and the insertion loss of the AWG type optical multiplexer / demultiplexer according to the second embodiment. FIG. 14 is a schematic cross-sectional side view of a main part of an AWG type optical multiplexer / demultiplexer according to the third embodiment. FIG. 15 is a schematic sectional side view of an essential part of an AWG type optical multiplexer / demultiplexer according to the fourth embodiment.

  Embodiments of an arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Moreover, in each drawing, the same code | symbol is attached | subjected suitably to the same or corresponding element. Furthermore, it should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual ones. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included.

(Embodiment 1)
FIG. 1 is a schematic top view of an AWG type optical multiplexer / demultiplexer 100 according to the first embodiment. FIG. 2 is a rear view of the AWG type optical multiplexer / demultiplexer 100 shown in FIG. 3 is a cross-sectional view of the AWG type optical multiplexer / demultiplexer 100 shown in FIG.

  As shown in FIGS. 1 to 3, the AWG type optical multiplexer / demultiplexer 100 includes an AWG chip 10, a base plate 20, a reference plate 30, a clip 40, a compensation member 50, and a warp mitigating member 51. ing.

  The AWG chip 10 is made of silica glass on a substrate made of silicon, quartz glass, or the like, and each waveguide constituting the AWG 10A, that is, a first input / output waveguide 10Aa to which light is input and output, and a first input. A first slab waveguide 10Ab connected to the output waveguide 10Aa, an array waveguide 10Ac connected to the first slab waveguide 10Ab, a second slab waveguide 10Ad connected to the array waveguide 10Ac, and a second This is a planar lightwave circuit (PLC) chip formed with a plurality of second input / output waveguides 10Ae connected to the slab waveguide 10Ad and through which light is input and output.

  The optical fiber core wire 2 to which the optical connector 1 is attached is connected to the first input / output waveguide 10Aa of the AWG chip 10. The optical fiber core 2 is for inputting / outputting signal light to / from the first input / output waveguide 10Aa. An optical fiber tape 4 to which an optical connector 3 is attached is connected to the second input / output waveguide 10Ae. The optical fiber tape 4 includes a plurality of optical fiber cores that are connected to the second input / output waveguides 10Ae and allow signal light to be input / output through the waveguides 10Ae.

  The arrayed waveguide 10Ac is configured such that channel waveguides having different lengths are arranged in parallel at a predetermined pitch. Each channel waveguide is bent in an arc shape and is arranged in the order of increasing length from the inner circumference side to the outer circumference side of the arc. The difference in optical path length between adjacent channel waveguides is the same. Further, the number of channel waveguides is set according to the number of channels of the input WDM signal light.

  The first slab waveguide 10Ab and the second slab waveguide 10Ad are linearly formed. Further, the first input / output waveguide 10Aa and the plurality of second input / output waveguides 10Ae are bent in an arc shape in a direction opposite to that of the array waveguide 10Ac. The number of the plurality of second input / output waveguides 10Ae is set to the number of channels of the WDM signal light to be used, for example, 40. Further, the AWG chip 10 has a shape (boomerang shape) bent along the outline shape of the AWG 10A.

  As shown in FIG. 3, the base plate 20 is bonded to the lower surface of the AWG chip 10 with an adhesive 61. The adhesive 61 is, for example, an epoxy ultraviolet curing adhesive. The base plate 20 is made of, for example, quartz glass. The base plate 20 is preferably made of a material having substantially the same linear expansion coefficient as the AWG chip 10, but is not particularly limited.

  The AWG chip 10 and the base plate 20 are cut into two at the cut surface C in a joined state, and separated into a fixed piece 71 and a movable piece 72. The cut surface C crosses the first slab waveguide 10Ab along a direction substantially perpendicular to the longitudinal direction of the first slab waveguide 10Ab, and is bent by about 90 degrees in the middle. Here, among the separated AWG chip 10 and the base plate 20, those included in the fixed piece 71 are referred to as an AWG chip fragment 11 and a base plate piece 21, respectively. Also, the AWG chip fragment 12 and the base plate piece 22 are included in the movable piece 72, respectively. The fixed piece 71 and the movable piece 72 are arranged with a groove G formed by the cut surface C therebetween. In order to suppress reflection and light loss due to the groove G in the first slab waveguide 10Ab, the groove G is preferably filled with matching oil or matching grease.

  As shown in FIG. 3, the reference plate 30 is joined to the fixed piece 71 and is brought into contact with the movable piece 72. That is, the fixed piece 71 is joined to the predetermined region 31 on the surface by, for example, an epoxy-based ultraviolet curable adhesive. On the other hand, the movable piece 72 is not joined to the fixed piece 71. Although the material which comprises the reference | standard board 30 is not specifically limited, For example, what consists of quartz glass can be used.

  As shown in FIGS. 1 and 2, the clip 40 sandwiches the reference plate 30 and the movable piece 72. As a result, a pressing force F as shown in FIG. 3 is applied to the reference plate 30 and the movable piece 72, and this pressing force F is set to such a magnitude that the movable piece 72 can slide on the reference plate 30. As the clip 40, for example, a so-called Zem clip can be used which is formed by bending a single rod made of metal such as steel.

  The compensation member 50 has a plate shape and is provided so as to be spanned between the fixed piece 71 and the movable piece 72, and is fixed to the fixed piece 71 and the movable piece 72 by an adhesive via a warp mitigating member 51. Has been. The compensation member 50 extends substantially parallel to the cut surface C in the first slab waveguide 10Ab. In the first embodiment, since the AWG chip 10 has a boomerang shape along the shape of the AWG 10A, the AWG chip 10 has no space for joining the compensation member 50. Therefore, the compensation member 50 is joined to the base plate pieces 21 and 22. The compensation member 50 is made of, for example, aluminum (for example, pure aluminum (JIS: A1050)). The compensation member 50 may have an anodized surface (anodized) on its surface.

  The warp mitigating member 51 is plate-shaped and has a linear expansion coefficient that is greater than or equal to the linear expansion coefficient of the base plate 20 (that is, the base plate piece 21 and the base plate piece 22) and less than the linear expansion coefficient of the compensation member 50. .

Next, the operation of the AWG type optical multiplexer / demultiplexer 100 will be described.
In the AWG chip 10 of the AWG type optical multiplexer / demultiplexer 100, when the WDM signal light having the wavelength-multiplexed signal lights is input from the first input / output waveguide 10Aa, the first slab waveguide 10Ab is the first slab waveguide 10Ab. The WDM signal light input from the input / output waveguide 10Aa is spread by diffraction and input to the arrayed waveguide 10Ac. The arrayed waveguide 10Ac adds a phase difference to the signal light included in the WDM signal light and inputs the signal light to the second slab waveguide 10Ad. The second slab waveguide 10Ad condenses each signal light having a different wavelength on each of the plurality of second input / output waveguides 10Ae by the phase difference added by the arrayed waveguide 10Ac. As a result, signal light having different wavelengths is demultiplexed and output from each of the plurality of second input / output waveguides 10Ae. Thus, the AWG type optical multiplexer / demultiplexer 100 functions as a wavelength division multiplexing optical demultiplexer.

  On the other hand, when signal light having a different wavelength is input from each of the plurality of second input / output waveguides 10Ae, an action opposite to the above-described action occurs due to the reciprocity of the light. From the first input / output waveguide 10Aa, A WDM signal light obtained by wavelength-multiplexing the signal light input from the plurality of second input / output waveguides 10Ae is output. In this case, the AWG type optical multiplexer / demultiplexer 100 functions as a wavelength division multiplexing optical multiplexer. Therefore, the AWG type optical multiplexer / demultiplexer 100 functions as a wavelength multiplexing optical multiplexer / demultiplexer.

  Here, in a normal AWG chip, since the refractive index of the material constituting the AWG chip is temperature-dependent, when the AWG chip changes in temperature, the wavelength of light collected on each of the plurality of second input / output waveguides Shift from the wavelength that should be collected. As a result, the light transmission center wavelength of the AWG chip is shifted.

  On the other hand, in the AWG type optical multiplexer / demultiplexer 100 according to the first embodiment, the movable member 72 is slid by the compensation member 50 extending and contracting in the direction D according to the temperature change of the AWG type optical multiplexer / demultiplexer 100. Thus, the temperature-dependent shift of the light transmission center wavelength of the AWG chip 10 is compensated by changing the relative position of the fixed piece 71 and the movable piece 72. As a result, athermalization of the AWG type optical multiplexer / demultiplexer 100 is realized.

  Furthermore, since the compensation member 50 extends substantially in parallel with the cut surface C in the first slab waveguide 10Ab, the expansion / contraction direction D is also substantially parallel to the cut surface C. Therefore, even when the compensation member 50 expands and contracts, the width of the groove G hardly changes. As a result, even if the compensation member 50 expands and contracts, the optical characteristics of the AWG type optical multiplexer / demultiplexer 100 are stabilized without fluctuation.

  The position correction amount dx by the compensation member 50 for compensating for the temperature-dependent shift of the light transmission center wavelength of the AWG chip 10 is set by the following equation (1) using the circuit parameters of the AWG chip 10 and the like. Can do.

Ｌ_ｆは第１スラブ導波路１０Ａｂの焦点距離、ΔＬはアレイ導波路１０Ａｃにおける隣接するチャネル導波路間の光路差、ｄはアレイ導波路１０Ａｃにおける隣接するチャネル導波路間のピッチ、ｎ_ｓは第１スラブ導波路１０Ａｂの実効屈折率、ｎ_ｇはアレイ導波路１０Ａｃの群屈折率、ｄλ／ｄＴは透過中心波長の温度依存性（たとえば０．０１１ｎｍ／℃）、ΔＴは温度変化量である。また、λ_０は第１スラブ導波路１０Ａｂにおいて回折角が０度になる波長であり、ＡＷＧの中心波長と呼ばれるものである。

L _f is the focal length of the first slab waveguide 10Ab, [Delta] L is the optical path difference between the channels adjacent waveguides in the arrayed waveguide 10Ac, d is the pitch between the channels adjacent waveguides in the arrayed waveguide 10Ac, n _s is the The effective refractive index of one slab waveguide 10Ab, _ng is the group refractive index of the arrayed waveguide 10Ac, dλ / dT is the temperature dependence of the transmission center wavelength (eg, 0.011 nm / ° C.), and ΔT is the amount of temperature change. Further, λ ₀ is a wavelength at which the diffraction angle becomes 0 degree in the first slab waveguide 10Ab, and is called a center wavelength of the AWG.

  When the temperature change amount is ΔT, the linear expansion coefficient and length of the compensation member 50 are set so that the movable piece 72 slides by the position correction amount dx expressed by the equation (1), thereby reducing the light of the AWG chip 10. A temperature-dependent shift of the transmission center wavelength can be compensated.

  In addition, since the clip 40 applies the pressing force F and sandwiches the reference plate 30 and the movable piece 72, the relative position between the fixed piece 71 and the movable piece 72 changes due to expansion and contraction of the compensation member 50. However, the fluctuation of the optical axis of the AWG type optical multiplexer / demultiplexer 100 is suppressed.

  Further, in the first embodiment, since the fixed piece 71 is joined to the reference plate 30, the clip 40 only needs to press the movable piece 72 against the reference plate 30. Thereby, the pressing force F to be applied by the clip 40 may be small. As a result, since a small and simple clip 40 can be used, the component cost is reduced. Further, since the clip 40 only needs to press the movable piece 72 against the reference plate 30, it is not necessary to use complicated and expensive parts such as a pressing board, and the cost can be reduced and the size can be reduced.

  Furthermore, in the first embodiment, the movable piece 72 to be clamped by the clip 40 has a smaller mass than the fixed piece 71 joined to the reference plate 30, so that a smaller and simpler clip 40 can be used. .

  Next, the compensation member 50 and the warp mitigating member 51 will be further described. 4 is a cross-sectional view taken along line YY of the AWG type optical multiplexer / demultiplexer 100 shown in FIG. As shown in FIG. 4, the compensation member 50 has two substantially rectangular parallelepiped convex portions 50a formed at both ends in the longitudinal direction. A warp mitigating member 51 is bonded to each of the two convex portions 50 a via an adhesive 62. Further, the two warp mitigating members 51 are respectively bonded to the base plate piece 21 included in the fixed piece 71 and the base plate piece 22 included in the movable piece 72 via an adhesive 63. Thus, the compensation member 50 is fixed to the base plate piece 21 and the base plate piece 22 via the adhesives 62 and 63, respectively, with the warp mitigating member 51 interposed. The adhesives 62 and 63 are, for example, epoxy-based ultraviolet curing adhesives.

  The warp mitigating member 51 has a linear expansion coefficient that is greater than or equal to the linear expansion coefficient of the base plate 20 (that is, the base plate piece 21 and the base plate piece 22) and less than the linear expansion coefficient of the compensation member 50. As a result, the variation in temperature dependence of the optical characteristics between the AWG type optical multiplexer / demultiplexers 100 is reduced, or the hysteresis caused by the temperature fluctuation is suppressed, so that the temperature dependence of the optical characteristics is improved.

  This will be specifically described below. In the structure of a known AWG type optical multiplexer / demultiplexer, the base plate and the compensation member are directly bonded with an adhesive. In this case, for example, when the temperature of the AWG type optical multiplexer / demultiplexer fluctuates due to fluctuations in the environmental temperature or the like, the linear expansion coefficient differs between the base plate and the compensation member. May occur and warp may occur. When such warpage occurs, a step may be generated between the two base plate pieces or between the two AWG chip pieces bonded to the base plate piece.

  FIG. 5 is a diagram illustrating a case where a step is generated between two base plate pieces. As shown in FIG. 5, when the base plate piece 22 and the compensation member 50 are directly bonded with the adhesive 64, warpage may occur in both the base plate 22 and the compensation member 50. When warping occurs, a step t is generated between the base plate piece 22 and the base plate piece 21. When the step t is generated in this way, the AWG chip fragment 12 bonded to the base plate piece 22 via the adhesive 61 and the AWG chip fragment 11 bonded to the base plate piece 21 existing on the back side of the paper surface. (See FIG. 1 etc.) There is also a step. As a result, the optical axes of the AWG chip fragment 11 and the AWG chip fragment 12 (that is, the optical axis of the first slab waveguide 10Ab formed across the AWG chip fragment 11 and the AWG chip fragment 12) are shifted. It becomes.

  Such a shift in the optical axis is corrected by the pressing force of the clip 40, but it causes a shift in the transmission center wavelength and an increase in insertion loss. Further, the deviation of the optical axis causes, for example, the generation of temperature hysteresis at the transmission center wavelength. Furthermore, if the pressing force of the clip 40 is increased in order to correct the deviation of the optical axis, the frictional force between the reference plate and the movable piece increases, which may further increase the temperature hysteresis.

  Further, the magnitude of the warp occurring in FIG. 5 also depends on the thickness of the adhesive 64. The thickness of the adhesive 64 is, for example, 2 μm to 10 μm, but it is difficult to keep the thickness of the adhesive 64 constant during manufacture. As a result, temperature dependent characteristics of optical characteristics such as transmission wavelength and insertion loss vary among AWG type optical multiplexers / demultiplexers.

For example, the base plate piece 22 is made of quartz glass (linear expansion coefficient; 4.3 × 10 ⁻⁷ / ° C., Young's modulus 73 GPa), and the compensation member 50 is pure aluminum (linear expansion coefficient; 2.3 × 10 ⁻⁵ / In the case where the temperature difference is t and the Young's modulus is 73 GPa), the step t at the center in the width direction of the AWG chip fragment 12 (near the optical axis of the first slab waveguide 10Ab) in the YY section is, for example, 4 μm. It was confirmed by calculation and actual measurement. In this case, warpage occurs in the V shape with the center in the width direction in the YY cross section of the bonded portion of the compensation member 50 as an axis. When the distance l between the center in the width direction of the part to which the compensation member 50 is bonded and the center in the width direction of the AWG chip fragment 12 is, for example, 8.0 mm, the warpage is about 1.5 μm.

  In contrast, in the first embodiment, the warp mitigating member 51 having a linear expansion coefficient that is greater than or equal to the linear expansion coefficient of the base plate 20 and less than the linear expansion coefficient of the compensation member 50 is used as the compensation member 50 and the base plate. Since it is interposed between the piece 21 and the base plate piece 22, the stress generated between the base plate 20 and the compensation member 50 during temperature fluctuation is relieved. Thereby, the curvature of the base plate piece 22 is suppressed. Accordingly, since the step t generated between the base plate piece 22 and the base plate piece 21 is reduced, the transmission center wavelength shift, the insertion loss is increased, the temperature hysteresis of the transmission center wavelength is generated, or the AWG type optical multiplexer / demultiplexer. Variations in the temperature-dependent characteristics of the optical characteristics are suppressed. As a result, the AWG type optical multiplexer / demultiplexer 100 according to the first embodiment has good temperature dependency of the optical characteristics.

  The linear expansion coefficient of the warp mitigating member 51 is more preferably a value closer to the linear expansion coefficient of the base plate 20 than the intermediate value between the linear expansion coefficient of the base plate 20 and the linear expansion coefficient of the compensation member 50. More preferably, it is the same value as the linear expansion coefficient of 20.

  Next, an example of a manufacturing method of the AWG type optical multiplexer / demultiplexer 100 according to the first embodiment will be described. First, an example of a method for manufacturing the AWG chip 10 will be described.

First, on the substrate made of silicon, quartz glass, or the like, a silica material (SiO ₂ glass particles) to be the lower cladding layer and the core layer is sequentially deposited by a flame deposition (FHD) method, and the deposited layer Is heated and made transparent. Next, a core layer is formed on the waveguide pattern of the plurality of AWGs 10A using photolithography and reactive ion etching. Next, an upper cladding layer is formed again by the FHD method so as to cover the upper and side portions of the waveguide pattern.

Next, as shown in FIG. 6, on the substrate S, a first input / output waveguide 10Aa, a first slab waveguide 10Ab, an arrayed waveguide 10Ac, a second slab waveguide 10Ad, and a plurality of second input / output waveguides are formed. A plurality of AWGs 10A formed of the waveguide 10Ae are cut along a cutting line L along the outline of the AWG 10A using a CO ₂ laser. Thereby, the boomerang-shaped AWG chip 10 along the outline shape of the AWG 10A can be obtained. The cutting may be performed using not only the CO ₂ laser but also various processing lasers, water jets, and the like.

  Thus, by forming a plurality of AWGs 10A on the substrate S with high density and cutting them into a boomerang shape along the outline of the AWG 10A to obtain the AWG chip 10, the substrate is cut into a rectangular shape including the AWG. Also, a larger number of AWG chips 10 can be obtained from one substrate S. As a result, the AWG chip 10 can be manufactured at low cost.

  Next, the base plate 20 is bonded to the manufactured AWG chip 10 with an adhesive 61 (see FIG. 3). Next, the AWG chip 10 and the base plate 20 are cut into two at the cut surface C in a joined state, and separated into a fixed piece 71 and a movable piece 72. Thereafter, the fixed piece 71 is joined to the reference plate 30 and the movable piece 72 is brought into contact therewith.

  On the other hand, as shown in the upper diagram of FIG. 7, the warp mitigating member 51 is bonded to each of the two convex portions 50 a of the compensation member 50 via an adhesive 62. At this time, if the warp mitigating member 51 is made of a material that transmits ultraviolet rays, such as quartz glass, the adhesive 62 can be irradiated with ultraviolet rays through the warp mitigating member 51 when the adhesive 62 is an ultraviolet curing adhesive. preferable. Thereafter, the compensation member 50 to which the warp mitigating member 51 is bonded is annealed at a temperature higher than the operating temperature of the AWG type optical multiplexer / demultiplexer 100 to relieve the stress of the adhesive 62 and remove the distortion. The annealing temperature is 90 ° C., for example.

  When the compensation member 50 to which the warp mitigating member 51 is bonded is lowered from the annealing temperature to room temperature, as shown in the middle diagram of FIG. 7, an arrow is caused by the difference in linear expansion coefficient between the warp mitigating member 51 and the compensating member 50. As shown in FIG. As a result, the warp mitigating member 51 and the compensation member 50 are warped.

  Thereafter, as shown in the lower diagram of FIG. 7, one warp mitigating member 51 is bonded to the base plate piece 22 via an adhesive 63. Similarly, the other warp mitigating member 51 is bonded to the base plate piece 21 via an adhesive 63. At this time, if the base plate pieces 21 and 22 are made of a material that transmits ultraviolet rays, such as quartz glass, the ultraviolet ray is passed through the base plate pieces 21 and 22 when the adhesive 63 is an ultraviolet curable adhesive. It is preferable because it can be irradiated. Thereafter, annealing is performed at a temperature higher than the operating temperature of the AWG type optical multiplexer / demultiplexer 100 as described above. In addition, since the warp of the warp mitigating member 51 and the compensating member 50 is absorbed by the adhesive 63, the warp is hardly transmitted to the base plate pieces 21 and 22.

  In this way, the warp mitigating member 51 is bonded to the compensation member 50 via the adhesive 62, and after annealing, the warp mitigating member 51 is bonded to the base plate pieces 21 and 22 via the adhesive 63. Since the fluctuation of the environmental temperature is large, the effect of suppressing the warp generated in the base plate pieces 21 and 22 by the warp mitigating member 51 is effectively exhibited.

  In addition, when the surface of the compensation member 50 is anodized, a sealing process may be performed to close the surface micropores in order to stabilize the surface state. Is preferable because the adhesive strength of the adhesive is increased. However, in the case of non-sealing holes, the adhesive strength varies depending on the time during which the surface is exposed to air from the alumite treatment to the time when the adhesive is applied, which causes the adhesive strength to vary. However, when the step of bonding the warp mitigating member 51 to the compensation member 50 and then bonding the warp mitigating member 51 to the base plate pieces 21 and 22 is performed, the warp mitigating member 51 is attached to the compensation member 50 after anodizing. Since it is easy to manage the time until bonding to be constant, the bonding strength between the compensation member 50 and the warp mitigating member 51 is stabilized.

  However, the effect of the warp mitigating member 51 does not depend on the order of steps. For example, as a process other than the above, the warp mitigating member 51 is bonded to the base plate pieces 21 and 22 via the adhesive 63, and then annealed, and then the warp mitigating member 51 is bonded to the warp mitigating member 51 via the adhesive 62. The process of adhering 50 may be performed. Alternatively, there may be a case in which the compensation member 50, the warp mitigating member 51, and the base plate pieces 21 and 22 are simultaneously bonded via the adhesives 62 and 63, and then annealing is performed. However, in any of these processes, since the warp mitigating member 51 has a linear expansion coefficient that is greater than or equal to the linear expansion coefficient of the base plate 20 and less than the linear expansion coefficient of the compensation member 50, the base plate 20 and the compensation member Since the stress between 50 is relieved, the warp of the base plate 20 is relieved.

  As described above, the AWG type optical multiplexer / demultiplexer 100 according to Embodiment 1 has good temperature dependency of optical characteristics.

(Example 1 and Comparative Example 1)
As Example 1 of the present invention, an AWG type optical multiplexer / demultiplexer having the configuration of Embodiment 1 shown in FIG. 1 was manufactured according to the above manufacturing method. As the compensation member, a pure aluminum (JIS: A1050) plate material whose entire surface was anodized and not sealed was used.

  Further, as Comparative Example 1, the same AWG type optical multiplexer / demultiplexer as in Example 1 except that the compensation member and the base plate piece are directly bonded with an adhesive without using the warp mitigating member as shown in FIG. Manufactured.

  FIG. 8 is a diagram illustrating circuit parameters of the AWG type optical multiplexer / demultiplexer according to the first embodiment and the first comparative example. Using this circuit parameter, the length of the compensation member was set to 18.0 mm.

  And about the AWG type | mold optical multiplexer / demultiplexer of Example 1 and Comparative Example 1, the level | step difference (refer FIG. 5) between baseplate pieces was measured. The steps were measured at measurement points P1, P2, and P3 corresponding to both ends and the center of the AWG chip pieces 11 and 12 of the AWG type optical multiplexer / demultiplexer 100 as shown in FIG. Also in Comparative Example 1, measurement was performed at the same measurement point. In addition, in both Example 1 and Comparative Example 1, measurement was performed with no clip attached.

  As a result, in the AWG type optical multiplexer / demultiplexer of Comparative Example 1, the steps at the measurement points P1, P2, and P3 were about 10 μm, about 7 μm, and about 3 μm, respectively, as average values of 10 samples. On the other hand, in the AWG type optical multiplexer / demultiplexer of Example 1, the steps at the measurement points P1, P2, and P3 were all 1 μm or less as an average value of 10 samples.

  Further, in the manufacturing process of the AWG type optical multiplexer / demultiplexer of Example 1, the warpage of the warp mitigation member after the warp mitigation member was bonded to the compensation member and annealed at 90 ° C. was measured to be about 1.5 μm. Warpage occurred. However, when the warp of the base plate piece of the manufactured AWG type optical multiplexer / demultiplexer of Example 1 was measured, almost no warp occurred.

  Next, with the clip attached to the AWG type optical multiplexer / demultiplexer of Example 1 and Comparative Example 1, 20 ° C. → 50 ° C. → 65 ° C. → 50 ° C. → 20 ° C. → −5 ° C. → 20 ° C. The variation of the transmission center wavelength and insertion loss was measured while changing the temperature.

  FIG. 10 is a diagram showing the temperature dependence of the transmission center wavelength and insertion loss variation of the AWG type optical multiplexer / demultiplexer according to the first embodiment. In the figure, “transmission center wavelength” and “insertion loss” are simply described as “center wavelength” and “loss”, respectively. As shown in FIG. 10, the AWG type optical multiplexer / demultiplexer of the first embodiment has a small variation in the transmission center wavelength and the insertion loss. The graph of the temperature dependence of the variation of the transmission center wavelength is in principle a smooth convex quadratic curve, but in FIG. 10 and FIGS. 11 and 13 below, in order to make the hysteresis easier to see, Data points at the measured temperature are connected by straight lines.

  FIG. 11 is a diagram showing the temperature dependence of the variation of the transmission center wavelength and the insertion loss for a certain sample of the AWG type optical multiplexer / demultiplexer of Comparative Example 1. As shown in FIG. 11, a certain sample of the AWG type optical multiplexer / demultiplexer of Comparative Example 1 had a large variation in transmission center wavelength and insertion loss, and a large hysteresis with respect to the transmission center wavelength. As described above, in Comparative Example 1, it is difficult to stably reduce the level difference in all samples, and some samples have deteriorated optical characteristics, resulting in variations in characteristics.

(Embodiment 2)
By the way, in the AWG type optical multiplexer / demultiplexer 100 according to the first embodiment, since the level difference between the base plate piece 22 and the base plate piece 21 is very small, the pressing force of the clip for correcting the level difference is small. May be. This further suppresses the occurrence of temperature hysteresis. Furthermore, the clip need not be used.

  FIG. 12 is a schematic top view of an AWG type optical multiplexer / demultiplexer according to Embodiment 2 of the present invention. As shown in FIG. 12, the AWG type optical multiplexer / demultiplexer 200 has the same configuration as the AWG type optical multiplexer / demultiplexer 100 according to Embodiment 1 except that the clip 40 is not used.

  Similar to the AWG type optical multiplexer / demultiplexer 100 according to the first embodiment, the AWG type optical multiplexer / demultiplexer 200 has a good temperature dependency of optical characteristics and does not use the clip 40, so the number of parts is reduced. And the occurrence of temperature hysteresis is further suppressed.

(Example 2)
As Example 2 of the present invention, an AWG type optical multiplexer / demultiplexer having the configuration of Embodiment 2 shown in FIG.

  FIG. 13 is a diagram illustrating the temperature dependence of the variation of the transmission center wavelength and the insertion loss of the AWG type optical multiplexer / demultiplexer according to the second embodiment. As shown in FIG. 13, in the AWG type optical multiplexer / demultiplexer of the second embodiment, the fluctuations in the transmission center wavelength and the insertion loss are as small as those in the first embodiment shown in FIG.

(Embodiment 3)
In the first and second embodiments, the warp mitigating member is provided so as to be interposed between the base plate and the compensation member. On the other hand, in the AWG type | mold optical multiplexer / demultiplexer which concerns on Embodiment 3 of this invention, the curvature reduction member is provided so that a compensation member may interpose between the said curvature reduction member and a base plate.

  FIG. 14 is a schematic cross-sectional side view of an essential part of an AWG type optical multiplexer / demultiplexer according to Embodiment 3 of the present invention. Since the first embodiment and the third embodiment are different only in the positional relationship among the warp mitigating member, the base plate, and the compensation member, this point will be described below.

  As shown in FIG. 14, in the AWG type optical multiplexer / demultiplexer 300 according to the third embodiment, one warp mitigating member 51 has a compensating member 50 interposed between the warp mitigating member 51 and the base plate piece 22. It is provided as follows. Similarly, the other warp mitigating member 51 is also provided so that the compensation member 50 is interposed between the warp mitigating member 51 and the base plate piece 21. Specifically, the compensation member 50 is bonded to the base plate pieces 21 and 22 via the adhesive 63 at the convex portion 50a. In addition, it is preferable to have the convex portion 50a as described above, because the adhesion area between the compensation member 50 and the base plate pieces 21 and 22 can be easily managed to be constant. Further, the warp mitigating member 51 is bonded to the compensation member 50 via the adhesive 62 on the side opposite to the side where the convex portion 50a is provided.

  In the AWG type optical multiplexer / demultiplexer 300, since the stress to be generated between the compensation member 50 and the base plate pieces 21 and 22 is also borne by the warp mitigation member 51 side, the compensation member 50 and the base plate pieces 21 and 22 are provided. The stress generated between the two is relaxed. As a result, warpage occurring in the base plate pieces 21 and 22 is suppressed, and the step between the base plate pieces 21 and 22 is also reduced. As a result, the AWG type optical multiplexer / demultiplexer 300 according to the third embodiment has good temperature dependency of the optical characteristics.

  Thus, the region where the warp mitigating member 51 is bonded to the compensation member 50 is a region where the stress generated between the compensating member 50 and the base plate pieces 21 and 22 is mitigated by the presence of the warp mitigating member 51. If it is.

  In the first to third embodiments, the adhesive surface between the warp mitigating member 51 and the base plate 20 (the base plate pieces 21 and 22) and the adhesive surface between the warp mitigating member 51 and the compensation member 50 are substantially parallel. However, it may be non-parallel.

(Embodiment 4)
FIG. 15 is a schematic cross-sectional side view of a main part of an AWG type optical multiplexer / demultiplexer according to Embodiment 4 of the present invention. Since the first embodiment and the fourth embodiment differ only in the positional relationship between the warp mitigating member, the base plate, and the compensation member, and only the shapes of the warp mitigating member and the compensation member, this point will be described below.

  In the AWG type optical multiplexer / demultiplexer 400 according to the fourth embodiment, the warp mitigating member 451 is provided so as to be interposed between the base plate pieces 21 and 22 and the compensation member 450. However, the warp mitigating member 451 has a rectangular parallelepiped shape, for example. Further, the compensation member 450 is, for example, a plate shape without a convex portion. The compensation member 450 is bonded to the side surface 451a of the warp mitigating member 451 via the adhesive 462 on the side surface 450a. The warp mitigating member 451 is bonded to the base plate pieces 21 and 22 via an adhesive 463. Here, the adhesives 462 and 463 are, for example, epoxy ultraviolet curing adhesives.

  Thus, even if the adhesion surface between the warp mitigation member 451 and the base plate 20 (the base plate pieces 21 and 22) and the adhesion surface between the warp mitigation member 451 and the compensation member 450 are substantially perpendicular, the warp mitigation member 451. As a result, the stress generated between the base plate 20 and the compensation member 450 is relieved. As a result, the AWG type optical multiplexer / demultiplexer 400 according to the fourth embodiment has good temperature dependence of optical characteristics.

  In the fourth embodiment, the adhesive surface between the warp mitigating member 451 and the base plate 20 (the base plate pieces 21 and 22) and the adhesive surface between the warp mitigating member 451 and the compensation member 450 are substantially perpendicular to each other. The surface may be in another non-parallel state, for example acute or obtuse. For example, the warp mitigating member 451 may have a wedge shape, the side surface 451a may be inclined, and the side surface 450a of the compensation member 450 may also be inclined corresponding to the side surface 451a.

  Further, in the fourth embodiment, if the warp mitigating member 451 is made of a material that transmits ultraviolet rays, the ultraviolet rays are passed through the warp mitigating member 451 to the adhesive 62 when the adhesives 462 and 463 are ultraviolet curable adhesives. Can be irradiated. In this case, the base plate 20 (base plate pieces 21 and 22) may not be made of a material that transmits ultraviolet light, and may be made of a material such as silicon having a linear expansion coefficient larger than that of quartz glass. .

  In the above embodiment, an epoxy ultraviolet curable adhesive is used as the adhesive, but a thermosetting adhesive may be used. Further, when the compensation member is bonded to the base plate or the warp mitigating member with an adhesive, it is preferable to clean the surface of the compensation member with an organic solvent, plasma, or the like because the surface wettability is improved and the adhesive strength is further increased. . Further, if a coupling agent such as a silane coupling agent is applied to the surface of the compensation member, the base plate, or the warp mitigating member to be bonded, and the adhesive is bonded with the adhesive via the coupling agent, the adhesive strength is further increased. Therefore, it is preferable.

  In the above embodiment, the smaller one of the AWG chips cut and separated is pressed with a clip as a movable piece. However, the larger piece is pressed with a clip as a movable piece. May be. That is, only one of the separated AWG chips is pressed against the reference plate with the clip, and the other is joined and fixed to the reference plate, whereby the clip can be made small and simple.

  In the above embodiment, the first slab waveguide is cut and separated. However, the second slab waveguide or both the first slab waveguide and the second slab waveguide are cut and separated. It may be.

  Moreover, in the said embodiment, in order to slide a movable piece smoothly, uneven | corrugated processes, such as a frost process, or a groove | channel may be provided in the surface of a reference | standard board, and a hollow part may be formed. As long as such a hollow part reduces the contact area of a movable piece and a reference | standard board, the aspect will not be specifically limited. Moreover, when providing a groove | channel, the extending direction is not restricted to the direction along the cut surface of an AWG chip | tip, A direction perpendicular | vertical to a cut surface may be sufficient.

  Further, the constituent materials of the base plate and the reference plate are not limited to quartz glass. If the length of the compensation member is determined in consideration of the linear expansion coefficients of the constituent materials of the base plate and the reference plate, various materials such as metals, semiconductors, and ceramics can be used.

  Further, the compensation member is not limited to aluminum or aluminum subjected to alumite treatment, but may be other metal such as copper or surface treatment for preventing alteration thereof.

  Further, the position where the AWG chip and the base plate are joined and the position where the compensation member is bridged are not limited to those in the embodiment, and the position of the AWG chip cut by expansion and contraction of the compensation member can be changed relatively. Any position is acceptable.

  Furthermore, in the above-described embodiment, the arrayed waveguide diffraction grating chip and the base plate are cut into two at the cutting plane crossing the first slab waveguide to form a fixed piece and a movable piece. However, the base plate does not necessarily have to be completely cut, and may be cut in part along the cut surface of the arrayed waveguide grating chip and connected in part. In this case, if the compensation member is stretched over the region of the base plate separated by the cut surface, when the compensation member expands and contracts, the relative position between the separated portions changes with the connected portion as a fulcrum. It will be. As a result, the relative position between the cut pieces of the arrayed waveguide grating chip changes. The change amount of the relative position may be adjusted to a change amount that compensates for the shift of the transmission center wavelength depending on the temperature change.

  Moreover, in the said embodiment, although a board | substrate is cut | disconnected along the outline shape of AWG and the boomerang-shaped AWG chip | tip is obtained, a board | substrate may be cut | disconnected to a rectangle and you may make it obtain a rectangular AWG chip | tip.

  Further, the present invention is not limited by the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

1, 3 Optical connector 2 Optical fiber core wire 4 Optical fiber tape 10 AWG chip 10A AWG
10Aa first input / output waveguide 10Ab first slab waveguide 10Ac array waveguide 10Ad second slab waveguide 10Ae second input / output waveguide 11, 12 AWG chip fragment 20 base plate 21, 22 base plate piece 30 reference plate 40 clip 50, 450 Compensation member 50a Convex part 51, 451 Warp mitigation member 61, 62, 63, 64, 462, 463 Adhesive 71 Fixed piece 72 Movable piece 100, 200, 300, 400 AWG type optical multiplexer / demultiplexer C Cut surface D Direction F Pressing force G Groove L Cutting line P1, P2, P3 Measurement point S Substrate

Claims (10)

A first input / output waveguide through which light is input / output, a first slab waveguide connected to the first input / output waveguide, and a first slab waveguide connected to the first slab waveguide and having different lengths and arranged in parallel An arrayed waveguide composed of a plurality of channel waveguides, a second slab waveguide connected to the arrayed waveguide, and a plurality of second connected to the second slab waveguide and to which light is input and output An input / output waveguide, and an arrayed waveguide grating chip cut in two at a cutting plane crossing the first slab waveguide or the second slab waveguide;
A base plate bonded to the lower surface of the arrayed waveguide grating chip and cut at least partially along the cut surface of the arrayed waveguide grating chip;
Relative relation between each of the cut arrayed waveguide grating chips fixed by an adhesive so as to be stretched over a region of the base plate separated by the cut surface, and expanded and contracted according to a temperature change. A compensation member that compensates for the temperature-dependent shift of the light transmission center wavelength of the arrayed waveguide grating by changing the position;
It has a linear expansion coefficient that is greater than or equal to the linear expansion coefficient of the base plate and less than the linear expansion coefficient of the compensation member, and uses an adhesive so as to relieve stress generated between the base plate and the compensation member. A warp mitigating member bonded to the compensation member;
An arrayed waveguide diffraction grating type optical multiplexer / demultiplexer comprising:   2. The arrayed waveguide grating optical multiplexer / demultiplexer according to claim 1, wherein the warp mitigating member is provided so as to be interposed between the base plate and the compensation member.   2. The arrayed waveguide grating optical multiplexing / demultiplexing according to claim 1, wherein the warp mitigating member is provided such that the compensation member is interposed between the warp mitigating member and the base plate. 3. vessel.   4. The array guide according to claim 1, wherein an adhesive surface between the warp mitigating member and the base plate and an adhesive surface between the warp mitigating member and the compensation member are substantially parallel. Waveguide diffraction grating type optical multiplexer / demultiplexer.   4. The array guide according to claim 1, wherein an adhesive surface between the warp mitigating member and the base plate and an adhesive surface between the warp mitigating member and the compensation member are non-parallel. Waveguide diffraction grating type optical multiplexer / demultiplexer.   6. The arrayed waveguide grating optical multiplexer / demultiplexer according to claim 1, wherein the warp mitigating member is made of a material that transmits ultraviolet rays.   7. The arrayed waveguide grating optical multiplexer / demultiplexer according to claim 1, wherein the warp mitigating member and the base plate have the same linear expansion coefficient. The arrayed waveguide diffraction grating chip and the base plate are cut into two at the cutting plane crossing the first slab waveguide or the second slab waveguide to form a fixed piece and a movable piece. ,
8. The arrayed waveguide grating optical system according to claim 1, wherein the compensation member is provided so as to be spanned between the fixed piece and the movable piece. Duplexer.   A reference plate on which the fixed piece is joined and the movable piece is in contact; and a clip that sandwiches the reference plate and the movable piece so that the movable piece can slide on the reference plate. The arrayed waveguide diffraction grating type optical multiplexer / demultiplexer according to claim 8.   The arrayed waveguide grating type optical combining according to any one of claims 1 to 9, wherein the arrayed waveguide grating chip has a shape along a contour shape of the arrayed waveguide grating. Waver.

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