JP2001154043A - Optical wavelength multiplexer/demultiplexer and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical wavelength multiplexer/demultiplexer, where a dividing wavelength is correctly controlled and temperature independency is established, and to provide its manufacturing method. SOLUTION: In this optical wavelength multiplexer/demultiplexer 1, where an optical circuit is formed by preparing on a substrate 2, an array waveguide diffraction grating 4 consisting of plural channel waveguides 3, an input side slab waveguide 5 connected to the array waveguide diffraction grating 4 and an output side slab waveguide 6, an input port 7 connected to the input side slab waveguide 5 and an output port 3 connected to the output side slab waveguide 6 are prepared, a groove 9 is formed in either of a part of these input and output side slab waveguides 5, 6 or a part of the array waveguide diffraction grating 4, and temperature independency is established by filling into the groove material having a temperature gradient of a refractive index different of that of material composing the optical circuit, the array waveguide diffraction grating 4 is irradiated with light to control the refractive index of the array waveguide diffraction grating 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength multiplexer / demultiplexer used for performing wavelength division multiplexing transmission in the field of optical communication and a method of manufacturing the same, and more particularly to a temperature independent optical wavelength multiplexer / demultiplexer. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength multiplexer / demultiplexer that irradiates light to an arrayed waveguide diffraction grating of a waveguide and controls a refractive index of the arrayed waveguide diffraction grating, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In the field of optical communication, a wavelength division multiplexing method has been studied, in which a plurality of signals are put on lights of different wavelengths and transmitted through a single optical fiber to increase the information capacity.
In this method, an optical wavelength multiplexer / demultiplexer that multiplexes / demultiplexes light having different wavelengths plays an important role. Above all, the optical wavelength multiplexer / demultiplexer using the arrayed waveguide diffraction grating can realize the multiplexing / demultiplexing at a narrow wavelength interval, and has an advantage that the multiplexing number of the communication capacity can be easily increased.

FIG. 6 shows an optical circuit of a conventional arrayed waveguide diffraction grating type optical wavelength multiplexer / demultiplexer 60. This optical wavelength multiplexer / demultiplexer 60 is connected to an arrayed waveguide diffraction grating 63 composed of a plurality of channel waveguides 62 (hereinafter, referred to as an arrayed waveguide 62) on a substrate 61, and to the arrayed waveguide diffraction grating 63. Input slab waveguide 64 and output slab waveguide 6
5, and further, an input channel waveguide 66 connected to the input side slab waveguide 64 and an output channel waveguide 67 connected to the output side slab waveguide 65 are formed. It was done.

In the conventional optical wavelength multiplexer / demultiplexer 60, a light wave input from the input channel waveguide 66 propagates in the input side slab waveguide 64 and reaches a boundary with the arrayed waveguide diffraction grating 63. The arriving light wave is coupled and propagates to each array waveguide 62 at a power ratio according to the electric field distribution at the boundary, and reaches the boundary between the array waveguide 62 and the output side slab waveguide 65.

The length of the array waveguide 62 is ΔL from the inside.
It is designed to be longer for every fixed length. Therefore, the phase variation light wave propagated through the i-th arrayed waveguide 62 receives phi _'i (lambda) from the inside, the wavelength of the light wave in vacuum and lambda, the equivalent refractive index of the arrayed waveguide 62 n _a The following equation is given based on the innermost arrayed waveguide 62.

[0006]

(Equation 1)

Therefore, the equiphase plane of the light wave near the boundary between the arrayed waveguide 62 and the output side slab waveguide 65 is inclined depending on the wavelength. The light waves that have undergone a phase change by each array waveguide 62 cause interference in the output side slab waveguide 65, and this interference wave is extracted from the output channel waveguide 67.

Here, since the direction of the equal phase plane is different for each wavelength, when the wavelength changes, the light condensing position shifts at the boundary between the output side slab waveguide 65 and each output channel waveguide 67. For this reason, each output channel waveguide 67
Can extract only a light wave having a unique demultiplexing wavelength, and a multiplexing / demultiplexing function of the light wave is realized. The wavelength λ of the light wave output from the output channel waveguide 67 disposed on the axis of symmetry 68 of the output side slab waveguide 65 is represented by the following equation, where the diffraction order is m.

[0009]

(Equation 2)

When an optical circuit is formed using ordinary materials, when the temperature changes, the refractive index of the material changes due to the thermo-optic effect, and as a result, n _a changes. Further, the length of the arrayed waveguide 62 changes due to thermal expansion, which also changes ΔL. Therefore, the equal phase plane of the light wave near the boundary between the arrayed waveguide 4 and the output side slab waveguide 5 is inclined due to the temperature, and the output demultiplexed wavelength changes. In the case of a light wave output from the output channel waveguide 67 disposed on the axis of symmetry 68 of the output side slab waveguide 65, the wavelength change amount Δλ when the temperature T changes by ΔT is expressed by Equation 2 By differentiating with T,

[0011]

(Equation 3)

## EQU1 ##

[0013] Here, consider the case of a configuration using a quartz-based material as an example, dn _a / dT is the equal to the temperature coefficient of the refractive index of the silica-based material, dn _a / dT is approximately 1 × 1
0 ^-5 , (1 / ΔL) · d (ΔL) / dT is approximately 5 × 1
0 ^-7, since n _a is approximately 1.45, λ = 1550 [n
m], Δλ / ΔT is approximately 0.01 [nm / ° C.]
Becomes Therefore, for example, when used at an environmental temperature of 0 to 60 ° C., the demultiplexing wavelength is shifted by a maximum of 0.6 nm. Therefore, it cannot be used in a practical system as it is, and it is necessary to control the temperature of the optical circuit by a heater or a Peltier element.

Therefore, as a method of eliminating the wavelength shift due to temperature and using it in a practical system without controlling the temperature, conventionally, as shown in FIG. There is a method in which a material having a temperature coefficient of refractive index different from that of the optical circuit is filled to cancel the inclination of the equal phase plane due to temperature. This method is based on Y. "Athermal silica-based arrayed-waveguide gr
ating (AWG) multiplexer ", ECOC97technical digest, pp.3
3-36, 1997.

According to the conventional optical wavelength multiplexer / demultiplexer 70 shown in FIG. 7, in a configuration having several hundred waveguides, a wedge-shaped groove 71 is provided.
The diffraction width increases because the maximum width of
A large additional loss of about 4 to 6 dB was generated.

In order to obtain good demultiplexing characteristics with small crosstalk, a high-precision groove width, whose width is smoothly changed to sub-μm or less, is generally required, but as shown in FIG. If it is attempted to form the groove 71, it is difficult to increase the processing accuracy, so that crosstalk has been degraded.

On the other hand, as proposed in Japanese Patent Application No. 11-226875, that is, in the optical wavelength multiplexer / demultiplexer 80 shown in FIG. 8, the temperature compensating member 81 is connected to the input side slab waveguide 64 or the output side. By providing the slab waveguide 65,
The thickness can be reduced, and additional loss and crosstalk can be reduced.

In an optical wavelength multiplexer / demultiplexer actually manufactured, a deviation occurs between a split wavelength and a desired wavelength to be split due to fluctuations in the manufacturing process of the optical circuit. It is important to eliminate this deviation and make the demultiplexed wavelength coincide with the desired wavelength.

In an optical wavelength multiplexer / demultiplexer in which a demultiplexing wavelength shift occurs due to temperature, the temperature dependence of the demultiplexing wavelength is positively utilized to accurately control the temperature of a heater or a Peltier element, thereby achieving demultiplexing. It is possible to match the wavelength with the desired wavelength.

On the other hand, this method cannot be used in an optical wavelength multiplexer / demultiplexer in which the demultiplexing wavelength is made temperature-independent. Therefore, in order to control the splitting wavelength, there has been a method in which an optical fiber is directly connected to the end of the input side slab waveguide, and the splitting wavelength is controlled by the connection position of the optical fiber. This method is similar to the method described in Y. "Athermal silica-based arra" by Inoue et al.
yed-waveguide grating (AWG) multiplexer ", ECOC97techn
ical digest, pp. 33-36, 1997.

[0021]

However, in this method, even if the connection position of the optical fiber is slightly shifted, a shift occurs between the demultiplexed wavelength and the desired wavelength.

Further, even if the demultiplexing wavelength can be accurately adjusted to a desired wavelength, if a stress is applied to the substrate in a subsequent mounting process, the refractive index of the material changes due to the photoelastic effect. Therefore, there is a possibility that the demultiplexing wavelength is shifted. In particular, in the step of bonding the substrate to the inner tray that directly supports the substrate, there is a problem that the largest stress is applied and the wavelength of the demultiplexed light varies greatly.

It should be noted that JP-A-7-294756, JP-A-10-282352 and JP-A-10-3329.
No. 57 and Japanese Patent Application Laid-Open No. 10-332971 disclose related techniques.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature-independent optical wavelength multiplexer / demultiplexer in which the demultiplexing wavelength is accurately controlled and a method of manufacturing the same.

[0025]

In order to achieve the above object, the present invention provides an array waveguide diffraction grating comprising a plurality of channel waveguides on a substrate, and an array waveguide diffraction grating comprising the same. An input slab waveguide connected to the grating;
An output side slab waveguide is formed to form an optical circuit, and an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided. A groove was formed in either a part or a part of the arrayed waveguide diffraction grating, and the groove was filled with a material having a temperature gradient of a refractive index different from that of the material constituting the optical circuit, thereby making the temperature independent. The optical wavelength multiplexer / demultiplexer is an optical wavelength multiplexer / demultiplexer in which the array waveguide diffraction grating is irradiated with light to control the refractive index of the array waveguide diffraction grating.

According to a second aspect of the present invention, the substrate is bonded to the inner tray, and thereafter, the arrayed waveguide grating is irradiated with light to control the refractive index of the arrayed waveguide grating. It is a wave device.

According to a third aspect of the present invention, there is provided the optical wavelength multiplexer / demultiplexer according to the first or second aspect, wherein the substrate is made of a quartz material, and the core of the optical circuit contains germanium.

According to a fourth aspect of the present invention, there is provided an arrayed waveguide grating comprising a plurality of channel waveguides, an input slab waveguide connected to the arrayed waveguide grating, and
An output side slab waveguide is formed to form an optical circuit, and an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided. A groove was formed in either a part or a part of the arrayed waveguide diffraction grating, and the groove was filled with a material having a temperature gradient of a refractive index different from that of the material constituting the optical circuit, thereby making the temperature independent. The method for manufacturing an optical wavelength multiplexer / demultiplexer includes a step of irradiating the arrayed waveguide grating with light to control the refractive index of the arrayed waveguide grating.

According to a fifth aspect of the present invention, there is provided an arrayed waveguide diffraction grating comprising a plurality of channel waveguides on a substrate, and an input side slab waveguide connected to the arrayed waveguide diffraction grating.
An output side slab waveguide is formed to form an optical circuit, and an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided. A groove was formed in either a part or a part of the arrayed waveguide diffraction grating, and the groove was filled with a material having a temperature gradient of a refractive index different from that of the material constituting the optical circuit, thereby making the temperature independent. In a method of manufacturing an optical wavelength multiplexer / demultiplexer, a step of connecting an input port or an output port for adjusting a demultiplexed wavelength to a desired wavelength, and irradiating the arrayed waveguide grating with light to form an arrayed waveguide grating. Controlling the refractive index of the optical wavelength multiplexer / demultiplexer.

According to a sixth aspect of the present invention, there is provided an arrayed waveguide diffraction grating comprising a plurality of channel waveguides on a substrate, and an input side slab waveguide connected to the arrayed waveguide diffraction grating.
An output side slab waveguide is formed to form an optical circuit, and an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided. A groove was formed in either a part or a part of the arrayed waveguide diffraction grating, and the groove was filled with a material having a temperature gradient of a refractive index different from that of the material constituting the optical circuit, thereby making the temperature independent. In a method of manufacturing an optical wavelength multiplexer / demultiplexer, a step of connecting an input port or an output port for adjusting a demultiplexed wavelength to a desired wavelength, a step of bonding a substrate and an inner tray, Irradiating light to control the refractive index of the arrayed waveguide diffraction grating.

According to a seventh aspect of the present invention, there is provided the optical wavelength multiplexing / demultiplexing apparatus according to any one of the fourth to sixth aspects, wherein the material constituting the substrate is a quartz-based material and the core of the optical circuit contains germanium. It is a manufacturing method of the container.

The invention according to claim 8 is the method for manufacturing an optical wavelength multiplexer / demultiplexer according to any one of claims 4 to 7, wherein the light source used for light irradiation is a carbon dioxide laser, an excimer laser, or an Ar ion laser. is there.

According to the above configuration, even if stress is applied to the substrate in the mounting process and the refractive index of the material changes due to the photoelastic effect and the wavelength of the demultiplexed light shifts, the array waveguide diffraction grating is irradiated with light to form an array. By controlling the refractive index of the waveguide diffraction grating, it is possible to suppress the shift of the demultiplexing wavelength.

Thus, a temperature-independent optical wavelength multiplexer / demultiplexer in which the demultiplexing wavelength is accurately controlled and a method of manufacturing the same are realized.

[0035]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of an optical wavelength multiplexer / demultiplexer according to a preferred embodiment of the present invention.

As shown in FIG. 1, an optical wavelength multiplexer / demultiplexer 1 according to the present invention includes a plurality of channel waveguides 3 a on a quartz substrate 2.
An arrayed waveguide diffraction grating 4 composed of 3b, 3c,..., An input side slab waveguide 5 connected to the arrayed waveguide diffraction grating 4, and an output side slab waveguide 6 are formed as an optical circuit. Input port 7 connected to slab waveguide 5
And an output port 8 connected to the output side slab waveguide 6, a groove 9 is formed in a part of the input side slab waveguide 5,
The groove 9 is filled with a material having a temperature gradient having a refractive index different from that of the material constituting the optical circuit so as to be independent of the temperature. After the quartz substrate 2 is mounted on the inner tray 10 by bonding, the array waveguide is formed. The diffraction grating 4 is irradiated with light to control the refractive index of the arrayed waveguide diffraction grating 4, and the inner tray 10 is connected to the outer tray 11.

The quartz substrate 2 has, for example, a structure in which a part of a flat plate is cut out so that the end face 12 of the input side slab waveguide 5 is exposed.

In the optical circuit, for example, a core made of a quartz-based material is formed on the quartz substrate 2, and the core constitutes the optical circuit. The core contains, for example, germanium. The core and the surface of the quartz substrate 2 are covered with a cladding film made of a quartz-based material.

Here, a description has been given of an example in which a quartz-based material core is used and the core contains germanium. However, if a material whose refractive index can be easily changed by light irradiation is used as the core, Any material may be used.

The groove 9 is filled with, for example, an optical resin 13 so as to realize a temperature-independent branching wavelength. This groove 9
May be formed on a part of the output side slab waveguide 6 or a part of the arrayed waveguide diffraction grating 4, for example.

The input port 7 comprises an input optical fiber 14 connected to the input side slab waveguide 5.

The input optical fiber 14 is connected to the outer tray 1.
1 is inserted through a hole or cutout groove 15 formed in the side surface of the device 1 and connected to the outside.

The output port 8 includes output channel waveguides 16a, 16b, 16c... Formed on the quartz substrate 2, and output optical fibers 17a, 17b connected to the output channel waveguides 16a, 16b, 16c. , 17c...

Output optical fibers 17a, 17b, 17c
Are connected to the outside by a connector 18 attached to the side surface of the outer tray 11.

The optical wavelength multiplexer / demultiplexer 1 according to the present invention is configured as described above.

Next, a method of manufacturing the optical wavelength multiplexer / demultiplexer according to the present invention will be described.

FIG. 2 is a flow chart showing a manufacturing process of the optical wavelength multiplexer / demultiplexer according to the present invention.

As shown in FIG. 2, the production of the optical wavelength multiplexer / demultiplexer starts at S0.

First, in step S 1, an optical circuit whose wavelength is made independent of temperature is manufactured on a quartz substrate 2. This step includes a step of manufacturing the groove 9 and a step of filling the groove 9 with the optical resin 13.

In the next step S2, the input port 7 is connected to the input side slab waveguide 5. The input port 7 in this embodiment is an input optical fiber 14.

This input port 7 connects the temperature-independent splitting wavelength so as to substantially match the desired wavelength to be split. This makes it possible to improve the controllability of the demultiplexing wavelength by reducing the irradiation amount of the light irradiation performed later, and to adjust the demultiplexing wavelength to a desired wavelength almost accurately.

In the next step S3, the output channel waveguides 16a, 16b, 16c,.
a, 17b, 17c...

In the next step S4, the quartz substrate 2 is bonded to the inner tray 10. During this step, stress is applied to the quartz substrate 2 by adhesion, and the refractive index of the optical circuit changes due to the photoelastic effect, and the demultiplexing wavelength may fluctuate.

In the next step S5, in order to correct the change in the refractive index of the optical circuit generated in the step S4, the array waveguide diffraction grating 4 is irradiated with light to control the refractive index of the array waveguide diffraction grating 4. The refractive index of the core is changed so that the demultiplexed wavelength matches the desired wavelength.

Here, the light irradiation in the present invention will be described in more detail.

FIG. 3 is a schematic view of a light irradiation device according to the present invention.

As shown in FIG. 3, a light irradiation device 30 according to the present invention comprises a KrF excimer laser 31 serving as a light source for light irradiation, a mirror 33 for adjusting the direction of the light beam 32,
A broadband light source 34 connected to the input optical fiber 14,
An optical spectrum analyzer 35 is connected to the output optical fiber 17.

First, the direction of the light beam 32 from the KrF excimer laser 31 is changed by the mirror 33 and is irradiated on the arrayed waveguide diffraction grating 4. Here, at the same time, light from the 1.55 μm band broadband light source 34 is input to the input optical fiber 14, and the split wavelength of output light from one of the output optical fibers 17 is measured by the optical spectrum analyzer 35. Light irradiation is performed until the demultiplexing wavelength reaches a desired wavelength.

As a result, the refractive index of the core of the optical circuit is changed to control the refractive index of the arrayed waveguide diffraction grating 4, so that the demultiplexed wavelength can be matched with a desired wavelength.

Although an example using a KrF excimer laser as a light source for light irradiation has been described, a carbon dioxide laser or an Ar ion laser may be used as a light source. That is, as the light source for light irradiation, any light source can be used as long as it has a large optical power and can generate a wavelength that is highly sensitive to germanium contained in the core.

The light irradiation in the present invention is performed as described above.

In the next step S6, the inner tray 10 is connected to the outer tray 11.

Then, in step S7, the manufacture of the optical wavelength multiplexer / demultiplexer is completed.

In this way, the optical wavelength multiplexer / demultiplexer of the present invention shown in FIG. 1 can be manufactured.

Next, the operation of the present invention will be described.

FIG. 4 is a diagram showing the relationship between the deviation between the demultiplexed wavelength and the desired wavelength at the end of each step in the present invention, with the horizontal axis taken at the end of each step and the vertical axis taken as the wavelength deviation.

As shown in FIG. 4, first, after the input port is connected in step S2, a wavelength deviation of -0.03 nm occurs due to a small controllability at the input port connection position.
After the connection of the output optical fiber in the next step S3, the value of the wavelength deviation does not substantially change.

After the inner tray is bonded in step S4, the bonding causes stress on the substrate.
The wavelength fluctuates by 0.04 nm, resulting in a total wavelength deviation of −0.07 nm. That is, in the conventional optical wavelength multiplexer / demultiplexer,
Since there is no light irradiation step in step S5, the demultiplexed wavelength of the manufactured optical wavelength multiplexer / demultiplexer deviates by -0.07 nm from the desired wavelength.

However, in the present invention, the refractive index of the core of the optical circuit is changed in the light irradiation step to control the refractive index of the arrayed waveguide diffraction grating 4 so that the demultiplexed wavelength matches the desired wavelength. Can be corrected, the wavelength deviation is corrected, and-
The wavelength deviation can be suppressed to 0.01 nm.

After the outer tray is connected in step S5, the wavelength deviation slightly deviates from -0.01 nm. According to the present invention, the temperature-independent optical wavelength multiplexing / demultiplexing in which the demultiplexing wavelength is accurately controlled. Container and its manufacturing method can be realized.

Next, an optical wavelength multiplexer / demultiplexer according to another embodiment of the present invention will be described.

FIG. 5 is a perspective view of an optical wavelength multiplexer / demultiplexer according to another embodiment of the present invention.

As shown in FIG. 5, the optical wavelength multiplexer / demultiplexer 5
Numeral 0 has the same configuration as the optical wavelength multiplexer / demultiplexer 1 shown in FIG. 1 except for the outer shape of the quartz substrate and the input port.

The quartz substrate 51 of the optical wavelength multiplexer / demultiplexer 50 has a flat plate shape.

The input port 52 comprises an input channel waveguide 53 formed on the quartz substrate 51 and an input optical fiber 54 connected to the input channel waveguide 53.

This optical wavelength multiplexer / demultiplexer 50 is suitable for a case where the variation in the amount of demultiplexed wavelength between optical circuits in the optical circuit manufacturing process is small.
2, the input port connection step is omitted, and in step S3,
The input optical fibers 54 of the optical wavelength multiplexer / demultiplexer 50 may be connected simultaneously.

In the optical wavelength multiplexer / demultiplexer and the method of manufacturing the same according to the present invention, when the variation in the wavelength of the demultiplexed light after bonding to the inner tray is small, the light irradiation step of step S5 is performed first. Then, the inner tray bonding step of step S4 may be performed.

Further, the order of step S2 and step S3 may be reversed.

In the above embodiments, the optical wavelength multiplexer / demultiplexer has been described. However, the present invention is not limited to these. For example, the optical wavelength multiplexer / demultiplexer used in the optical multiplex transmission system may be used. , M × N frequency routing device,
The present invention can also be used for an Add / Drop filter and the like and a method for manufacturing them.

[0081]

As is apparent from the above description,
According to the present invention, the following excellent effects are exhibited.

(1) A temperature-independent optical wavelength multiplexer / demultiplexer in which the demultiplexing wavelength is accurately controlled and a method of manufacturing the same can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a preferred embodiment of the present invention.

FIG. 2 is a flowchart of a manufacturing process of the optical wavelength multiplexer / demultiplexer shown in FIG.

FIG. 3 is a schematic view of a light irradiation device according to the present invention.

FIG. 4 is a diagram showing a relationship between a deviation between a demultiplexed wavelength and a desired wavelength at the end of each step in the present invention.

FIG. 5 is a perspective view showing another embodiment of the present invention.

FIG. 6 is a plan view showing an optical circuit of a conventional optical wavelength multiplexer / demultiplexer.

FIG. 7 is a plan view showing an optical circuit of a conventional optical wavelength multiplexer / demultiplexer.

FIG. 8 is a plan view showing an optical circuit of a conventional optical wavelength multiplexer / demultiplexer.

[Explanation of symbols]

 Reference Signs List 1 optical wavelength multiplexer / demultiplexer 2 quartz substrate 3 channel waveguide 4 arrayed waveguide diffraction grating 5 input side slab waveguide 6 output side slab waveguide 7 input port 8 output port 9 groove 10 inner tray 11 outer tray

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Naoto Uezuka 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture F-term in Opto-Systems Research Laboratory, Hitachi Cable, Ltd. 2H047 KA02 KA04 KA12 LA01 LA18 MA05 PA11 RA00 TA00 TA11

Claims (8)

[Claims] 1. An arrayed waveguide grating composed of a plurality of channel waveguides, an input slab waveguide connected to the arrayed waveguide grating, and an output slab waveguide formed on a substrate. As an optical circuit, an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided, and a part of the input / output slab waveguide or one of the arrayed waveguide diffraction gratings is provided. In an optical wavelength multiplexer / demultiplexer in which a temperature is made independent by filling a groove having a temperature gradient with a refractive index different from that of the material constituting the optical circuit, a groove is formed in one of the portions. An optical wavelength multiplexing / demultiplexing device, wherein a light is irradiated on a waveguide grating to control a refractive index of the arrayed waveguide grating. 2. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein the substrate is adhered to the inner tray, and thereafter, the array waveguide diffraction grating is irradiated with light to control the refractive index of the array waveguide diffraction grating. 3. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein the substrate is made of a quartz-based material, and the core of the optical circuit contains germanium. 4. An arrayed waveguide grating composed of a plurality of channel waveguides, an input slab waveguide connected to the arrayed waveguide grating, and an output slab waveguide formed on a substrate. As an optical circuit, an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided, and a part of the input / output slab waveguide or one of the arrayed waveguide diffraction gratings is provided. Forming a groove in any of the portions, and filling the groove with a material having a temperature gradient of a refractive index different from that of the material constituting the optical circuit to make the temperature independent optical wavelength multiplexer / demultiplexer. Irradiating the arrayed waveguide grating with light to control the refractive index of the arrayed waveguide grating. 5. An array waveguide diffraction grating comprising a plurality of channel waveguides, an input slab waveguide connected to the array waveguide diffraction grating, and an output slab waveguide formed on a substrate. As an optical circuit, an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided, and a part of the input / output slab waveguide or one of the arrayed waveguide diffraction gratings is provided. Forming a groove in any of the portions, and filling the groove with a material having a temperature gradient of a refractive index different from the material constituting the optical circuit to make the temperature independent optical wavelength multiplexer / demultiplexer. Connecting an input port or an output port for adjusting the demultiplexing wavelength to a desired wavelength, and controlling the refractive index of the arrayed waveguide grating by irradiating the arrayed waveguide grating with light. Features Of manufacturing optical wavelength multiplexer / demultiplexer. 6. An arrayed waveguide grating composed of a plurality of channel waveguides, an input slab waveguide connected to the arrayed waveguide grating, and an output slab waveguide formed on a substrate. As an optical circuit, an input port connected to the input side slab waveguide and an output port connected to the output side slab waveguide are provided, and a part of the input / output side slab waveguide or one of the arrayed waveguide diffraction gratings is provided. Forming a groove in any of the portions, and filling the groove with a material having a temperature gradient of a refractive index different from the material constituting the optical circuit to make the temperature independent optical wavelength multiplexer / demultiplexer. Connecting an input port or an output port for adjusting the demultiplexed wavelength to a desired wavelength, bonding the substrate and the inner tray, and irradiating the array waveguide diffraction grating with light to form the array waveguide diffraction grating. refraction Controlling the rate. A method for manufacturing an optical wavelength multiplexer / demultiplexer, comprising: 7. The method of manufacturing an optical wavelength multiplexer / demultiplexer according to claim 4, wherein the material forming the substrate is a quartz-based material, and the core of the optical circuit contains germanium. 8. The method according to claim 4, wherein the light source used for light irradiation is a carbon dioxide laser, an excimer laser, or an Ar ion laser.