JP2000292634A - Array waveguide diffraction grating type optical multiplexer/demultiplexer and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-loss and compact array waveguide diffraction grating type optical multiplexer/demultiplexer facilitating manufacture, and a manufacturing method. SOLUTION: A first channel waveguide for input/output 2, a first slab waveguide 3 connected to the first channel waveguide for input/output 2, an array waveguide part 4 comprising M (M>=2) of channel waveguides 41 to 4M with different optical path lengths connected to the first slab waveguide 3, a second slab waveguide 5 connected to the array waveguide part 4, and N (N>=2) of second channel waveguides for input/output 61 to 6N connected to the second slab waveguide 5 are formed on a base plate 1. A double refraction plate 7 is embedded in the course of the light path in the second slab waveguide 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer, which is a planar optical circuit component suitably used for multiplexing or demultiplexing multi-wavelength signal light in a wavelength division multiplexing communication system. The present invention relates to a manufacturing method thereof.

[0002]

2. Description of the Related Art An arrayed waveguide diffraction grating type optical multiplexer / demultiplexer is:
As shown in FIG. 5, at least one first input / output channel waveguide 2, a first slab waveguide 3 connected to the first input / output channel waveguide 2, and a first array waveguide portion 4 which the optical path length of each is connected to the slab waveguide 3 is different from a plurality of channel waveguides 4 ₁ to 4 _M to each other
When, a second slab waveguide 5 connected to the array waveguide portion 4, the second slab waveguide 5 connected to the plurality of second input-output channel waveguide 6 ₁ to 6 _N Are formed on the substrate 1.

In this array waveguide diffraction grating type optical multiplexer / demultiplexer, when light enters the input / output channel waveguide 2, the light sequentially passes through the slab waveguide 3, the array waveguide section 4, and the slab waveguide 5. demultiplexes light between which is guided, to output the respective light of each wavelength that demultiplexed to any of the N input-output channel waveguide 6 ₁ to 6 _N. The array waveguide diffraction grating type optical multiplexer / demultiplexer receives light of each wavelength into each of the _N input / output channel waveguides 6 _{1 to} 6 _N.
Light is multiplexed while sequentially guided through the slab waveguide 5, the arrayed waveguide section 4, and the slab waveguide 3, and the multiplexed light is output to the input / output channel waveguide 2. That is, the arrayed-waveguide grating type optical multiplexer / demultiplexer is used as an optical multiplexer / demultiplexer for multiplexing multi-wavelength signal light in a wavelength division multiplexing communication system.

In an arrayed waveguide grating type optical multiplexer / demultiplexer,
Input / output channel waveguide 2, slab waveguide 3, array conductor
Waveguide 4, slab waveguide 5, and input / output channel waveguide
Road 6 ₁~ 6_NAfter each high-temperature sintering,
Stress and strain due to the difference in thermal expansion coefficient when cooling
To stay. Each channel waveguide 4 of the array waveguide section 4₁~ 4_M
If residual stress exists in each core area,
TE mode light and TM mode light
The effective refractive indices for this are different from each other. You
That is, the effective refractive index for TE mode light is n_TEWhen
And the effective refractive index for the TM mode light is n_TMTo be
And when the substrate 1 is a silicon substrate, the thermal expansion coefficient difference
Is large, birefringence B = n_TE-N_TMIs 10^-Fourdegree
Up to

As described above, the T wave guided through the array waveguide portion 4
If the effective refractive indexes for the E mode light and the TM mode light are different from each other, the difference between the effective optical path lengths for the TE mode light and the TM mode light changes.
Then, as shown in FIG. 6, array waveguide portion 4 from the slab waveguide 5 the propagated output channel waveguide 6 ₁ to 6 _N
The positions at which they are incident are shifted by Δz.

[0006] different result, in the same TE mode light be a wavelength and TM mode light, the loss at the time of entering the channel waveguide 6 ₁ to 6 _N, respectively for input and output from the slab waveguide 5 from each other. That is, as shown in FIG. 7, the minimum loss peak wavelength is shifted by PDλ depending on the polarization state, and polarization dependence occurs. In particular, when the substrate 1 is a silicon substrate, the minimum loss peak wavelength shift PDλ is 0.1 nm to
It is about 0.4 nm, and the wavelength resolution as an optical multiplexer / demultiplexer is greatly deteriorated.

An arrayed waveguide diffraction grating type optical multiplexer / demultiplexer.
In the equation, the light propagation equation and the characteristic relational equation are:_s・ D · sin θ + n_c・ ΔL = m ・ λ (1) m = n_c・ ΔL / λ₀ ... (2) Δx / Δλ = fm / n_s/ D (3) PDλ = ΔL · B / m (4) B = n_TE-N_TM= K · σ (5) Here, as shown in FIG._cIs
Each channel waveguide 4 of the array waveguide section 4₁~ 4_MEffective
Index of refraction, n_sIs the effective refractive index of the slab waveguide 5
And d is each channel waveguide 4 of the array waveguide section 4.₁~
4_MIs the interval at the position in contact with the slab waveguide 5 of
L is each channel waveguide 4 of the array waveguide section 4 ₁~ 4_MBaby
It is the difference between two adjacent geometric lengths. m is the diffraction order
Λ is the wavelength of light and f is the number of slab waveguides 5
Focal length, λ₀Is the light obtained from the slab waveguide 5
Is the center wavelength. Δx is the input / output channel waveguide 6₁
~ 6_N, Δλ is the optical wavelength interval, and K is
Is the photoelastic coefficient of the waveguide, and σ is the stress of the waveguide.

Therefore, several proposals have been made to solve the problem of polarization dependence in such an arrayed waveguide grating optical multiplexer / demultiplexer. For example, Japanese Patent Application Laid-Open No. 4-241
304 No. those disclosed in Japanese, insert the lambda / 2 plate as a polarization rotator so as to cross each channel waveguide 4 ₁ to 4 _M, respectively of the central portion of the arrayed waveguide 4, the polarization The rotator converts the TE mode light and the TM mode light into each other, thereby eliminating the problem of polarization dependence. Those disclosed in Japanese Patent Laid-Open No. 5-157920 has a stress applying section such as amorphous silicon film of a specific shape provided on each of the channel waveguides 4 ₁ to 4 _M of the arrayed waveguide 4, the stress applying The residual stress is canceled by the stress given by the portion, thereby solving the problem of polarization dependence. In addition, Japanese Patent Application Laid-Open No. 4-163406
In this publication, two input / output channel waveguides 2 for inputting light to a slab waveguide 3 are provided, TE mode light is made incident on one input / output channel waveguide, and the other input / output channel waveguide is used. The TM mode light into the channel waveguide for
This eliminates the problem of polarization dependence.

[0009]

However, the array waveguide diffraction grating type optical multiplexer / demultiplexer disclosed in each of the above publications has the following problems.

In the structure disclosed in Japanese Patent Application Laid-Open No. Hei 4-241304, each channel waveguide 4 ₁ of the arrayed waveguide section 4 is provided.
Although the dimensions of the core cross section of each of ~ 4 _M are about 6 µm × 6 µm, the polarization rotator (λ /
2) has a thickness of 20 μm to 100 μm. Therefore, when light passes through the polarization rotator, diffraction occurs, and the diffraction loss becomes 0.3 dB or more.

In the structure disclosed in Japanese Patent Application Laid-Open No. 5-157920, each channel waveguide 4 ₁ of the arrayed waveguide section 4 is provided.
It is required that the film of the stress applying part provided on each of the ４4 _M has a specific shape. Therefore, when the stress applying portion is formed, steps of film formation, resist application, pattern processing, and resist peeling are required, and manufacturing is not easy.

Also, in the device disclosed in Japanese Patent Application Laid-Open No. 4-163406, in order to make light of mutually different polarization components incident on each of the two input / output channel waveguides 2,
It is necessary to provide a polarization separation circuit such as a Mach-Zehnder interferometer separately from the arrayed waveguide grating optical multiplexer / demultiplexer. Therefore, a circuit including both of them becomes complicated and large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a low-loss, easy-to-manufacture and compact array waveguide grating type optical multiplexer / demultiplexer and a method of manufacturing the same. I do.

[0014]

An array waveguide diffraction grating type optical multiplexer / demultiplexer according to the present invention is an array waveguide diffraction grating type optical multiplexer / demultiplexer formed on a substrate for multiplexing / demultiplexing light. (1) a first input / output terminal having first and second input / output terminals on the substrate, and outputting light to the second input / output terminal when light is input to the first input / output terminal Channel waveguide, (2) a first input / output end connected to the second input / output end of the first input / output channel waveguide, and when light is input to the first input / output end, A first slab waveguide having M (M ≧ 2) second input / output terminals for outputting light, and (3) one M input / output terminals of the M first input / output terminals of the first slab waveguide. A first input / output end connected to the pair, and a second input / output end outputting light when the light is input to the first input / output end, and each of the optical path lengths is a predetermined length. Different by (4) M first waveguides connected one-to-one to the second input / output terminals of each of the M channel waveguides in the array waveguide. N (N ≧ N) that outputs light when light is input to each of the input / output terminals of M and the M first input / output terminals.
(2) a second slab waveguide having two second input / output ends, and (5) a first slab waveguide connected to the N second input / output ends of the second slab waveguide in a one-to-one correspondence. , And N second input / output channel waveguides each having an input / output end and a second input / output end for outputting light when light enters the first input / output end. A birefringent flat plate is embedded between the first input / output end and the second input / output end of the second slab waveguide.

According to this arrayed waveguide grating type optical multiplexer / demultiplexer, the light input to the first input / output terminal of the first channel waveguide is transmitted to the first channel waveguide and the first slab waveguide. , And through the M channel waveguides forming the arrayed waveguide section, the signal is input to the second slab waveguide. In each of the M channel waveguides forming the array waveguide portion, the effective refractive index may differ depending on the polarization state due to residual stress. In this case, if the birefringent flat plate is not provided, when light enters the first input / output end of the second input / output channel waveguide, displacement occurs due to a difference in polarization state. However, in the present invention, since the birefringent flat plate is provided in the middle of the optical path of the second slab waveguide, this displacement is compensated. Then, light is efficiently incident on the first input / output end of the second input / output channel waveguide regardless of the polarization state. As described above, the polarization dependence at the time of input to the second input / output channel waveguide is reduced, and the shift amount of the minimum loss peak wavelength is reduced. In particular, the birefringent flat plate is preferably a rutile crystal plate.

Further, a phase difference compensating flat plate is buried between the first input / output terminal and the second input / output terminal of any of the first and second slab waveguides. I do. In this case, even if a phase difference occurs due to a difference in optical path length when light in each polarization state passes through the birefringent flat plate, the phase difference is provided because the phase difference compensating flat plate is provided. Compensated.

The method for manufacturing an arrayed waveguide grating type optical multiplexer / demultiplexer according to the present invention is a method for manufacturing an arrayed waveguide grating type optical multiplexer / demultiplexer formed on a substrate and for multiplexing / demultiplexing light. (1) a first input / output terminal having first and second input / output terminals on the substrate, and outputting light to the second input / output terminal when light is input to the first input / output terminal A channel waveguide for
(2) A first input / output terminal connected to the second input / output terminal of the first input / output channel waveguide, and M () outputs light when light is input to the first input / output terminal. (1) a first slab waveguide having M ≧ 2) second input / output terminals, and (3) one-to-one connection with the M second input / output terminals of the first slab waveguide. A first input / output end, and a second input / output end that outputs light when light is input to the first input / output end,
(4) One-to-one connection between the arrayed waveguide section composed of M channel waveguides having different optical path lengths by a predetermined length, and (4) the second input / output end of each of the M channel waveguides in the arrayed waveguide section. The M first input / output terminals connected to each other, and N outputs light when light is input to each of the M first input / output terminals.
(5) a second slab waveguide having (N ≧ 2) second input / output ends, and (5) one-to-one connected to the N second input / output ends of the second slab waveguide. The first input / output terminal and the first
And N second input / output channel waveguides each having a second input / output end for outputting light when light is input to the input / output end of the second slab waveguide. A groove is formed between the input / output terminal and the second input / output terminal, and a birefringent flat plate is buried in the groove and fixed by adhesion. Further, a groove is formed between the first input / output end and the second input / output end of any of the first and second slab waveguides,
A phase difference compensating flat plate is embedded and fixed in the groove. According to this manufacturing method, the above-described array waveguide diffraction grating type optical multiplexer / demultiplexer according to the present invention can be suitably manufactured.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a configuration diagram of an arrayed waveguide grating type optical multiplexer / demultiplexer according to this embodiment. The arrayed waveguide grating optical multiplexer / demultiplexer according to the present embodiment includes a first input / output channel waveguide 2 and a first input / output channel waveguide 2.
And a first slab waveguide 3 connected to the first slab waveguide 3 and having different optical path lengths M (M ≧ M).
2) array waveguide portion 4 composed of a channel waveguide 4 ₁ to 4 _M of this, a second slab waveguide 5 connected to the array waveguide portion 4, which is connected to the second slab waveguide 5 N (N ≧
2) The second input / output channel waveguides 6 _{1 to} 6 _N are:
The birefringent flat plate 7 is formed on the substrate 1 and is embedded in the optical path of the second slab waveguide 5.

In the following, description will be made on the assumption that the arrayed waveguide grating type optical multiplexer / demultiplexer according to the present embodiment is an optical demultiplexer. That is, the light input to the first input / output channel waveguide 2 is demultiplexed, and the demultiplexed light of each wavelength is transmitted to the N second input / output channel waveguides 6 _{1 to} 6 _N. Description will be made assuming a case of outputting to any of them.

The input / output channel waveguide 2 is a waveguide in which a region having a higher refractive index than the refractive index of the substrate 1 is formed in a channel shape. The input / output channel waveguide 2 is
An input end 2 a is provided on an end face of the substrate 1, and an output end 2 b for outputting light input to the input end 2 a is provided at a joint position with the slab waveguide 3.

The slab waveguide 3 is a waveguide in which a region having a higher refractive index than the refractive index of the substrate 1 is formed in a layer. The slab waveguide 3 allows light input from the output end 2b of the input / output channel waveguide 2 to the slab waveguide 3 to be input to the input end 4a of the arrayed waveguide unit 4 joined to the slab waveguide 3. .

The array waveguide section 4 is composed of _M channel waveguides 4 ₁ to 4 _M in which regions each having a higher refractive index than the refractive index of the substrate 1 are formed in a channel shape. The array waveguide section 4 has an input terminal 4 for inputting light from the slab waveguide 3.
a and an output end 4 b for outputting the light to the slab waveguide 5. Channel waveguides 4 ₁ to 4 _M of the M, each of the optical path length is different by a predetermined length [Delta] L, giving a phase difference to light guided through each.

The slab waveguide 5 is a waveguide in which a region having a higher refractive index than the refractive index of the substrate 1 is formed in a layer. The slab waveguide 5 is connected to the output end 4 of the array waveguide section 4.
b is input to the slab waveguide 5 by the birefringent flat plate 7.
Through, is inputted to the input terminal 6a of the slab waveguide 5 to the joint has been that output channel waveguide 6 ₁ to 6 _N.

The input / output channel waveguides 6 _{1 to} 6 _N are waveguides in which a region having a higher refractive index than the refractive index of the substrate 1 is formed in a channel shape. Each of the input / output channel waveguides 6 _{1 to} 6 _N outputs light input from the slab waveguide 5 to the input end 6 a to an output end 6 b provided on the end face of the substrate 1.

The birefringent flat plate 7 is located in the middle of the optical path in the slab waveguide 5, that is, the output end 4 of the array waveguide 4.
b and are embedded in a groove formed between the input end 6a of the input and output channel waveguides 6 ₁ to 6 _N. Birefringent flat plate 7
Separates light incident on one surface into an ordinary light component and an extraordinary light component, and for each of the ordinary light component and the extraordinary light component,
The light propagates through different optical paths and exits from different positions on the other surface.

Since the birefringent plate 7 is inserted into the slab waveguide 5 having a wide waveguide, the diffraction loss is small and the insertion loss is small. In addition, as the birefringent flat plate 7,
A rutile crystal plate in which the optical axis is set in a predetermined direction and the thickness is appropriately set is preferable. In this case, the workability is excellent, and the wavelength 1.5 which is generally used in optical communication is used.
The transmittance is high for signal light in the 5 μm band.

FIG. 2 is an explanatory diagram of the birefringent flat plate 7 in the arrayed waveguide grating optical multiplexer / demultiplexer according to the present embodiment. As shown in this figure, light that enters the slab waveguide 5 from the array waveguide section 4 and propagates through the slab waveguide 5 is
TE mode light and TM mode light are separated by birefringence caused by residual stress in the arrayed waveguide portion 4, and even if the wavelength is the same, each mode light enters the birefringent flat plate 7 through different paths. I do. The birefringent flat plate 7 outputs the input TE mode light and TM mode light by propagating them through different optical paths. Until the light is output from the birefringent flat plate 7 and is input to the input / output channel waveguide 6 _j , the TE mode light and the TM mode light propagate along the slab waveguide 5 along the same path.

That is, when the birefringent flat plate 7 is not provided, the displacement Δz between the TE mode light and the TM mode light incident on the input / output channel waveguide 6 _j is determined in the optical path of the slab waveguide 5. Is provided with a birefringent flat plate 7, a positional shift amount-[Delta] z between the TE mode light and the TM mode light is generated and compensated for. Accordingly, both of the TE mode light and TM mode light incident efficiently to the input and output channel waveguides 6 _j. As described above, the polarization dependence at the time of input to the input / output channel waveguide 6 _j is reduced, and as shown in FIG. 3, the deviation amount PDλ of the minimum loss peak wavelength becomes extremely small, for example, 0.05 nm or less. Is reduced to

Next, the operation of the arrayed waveguide grating type optical multiplexer / demultiplexer according to this embodiment will be described. Here, it is assumed that light input to the input end 2a of the input / output channel waveguide 2 includes light of wavelengths λ _{1 to} λ _N in a predetermined wavelength band, and light of wavelength λ _j is input / output channel waveguide 6. It shall be output to _j of the output terminal 6b (j = 1~N).

Light input to the arrayed waveguide grating type optical multiplexer / demultiplexer is guided through the input / output channel waveguide 2 and is input to the slab waveguide 3 from the output end 2b. The light input to the slab waveguide 3 propagates through the slab waveguide 3 while diffusing toward the input end 4 a of the arrayed waveguide section 4. Each wavelength component of the light input to the input end 4a of the arrayed waveguide section 4 is M
All channel waveguides 4 ₁ to 4 _M of the guided, output 4
b and input to the slab waveguide 5. And
Each wavelength component of the light is input-output channel waveguides 6 ₁
Guided while diffusing the slab waveguide 5 toward the input end 6a of 6 _N.

At this time, since the optical path lengths of the _M channel waveguides 4 ₁ to 4 _{M of} the arrayed waveguide section 4 are different from each other by a predetermined length, the light guided therethrough has a phase difference corresponding to the wavelength. Given. Further, M the channel waveguide 4 ₁ to 4 _M each has be made birefringent due to the residual stresses, are compensated by the birefringent plate-7 embedded in the slab waveguide 5. At the time when the light propagates through the _M channel waveguides 4 ₁ to 4 _M , the slab waveguide 5 and the birefringent flat plate 7 and reaches the input end 6 a of the input / output channel waveguide 6 _j , the polarization dependence is increased. And the light of wavelength λ _j reinforces, while the light of other wavelengths λ _k (k ≠ j) cancels out (j = 1 to
n). Therefore, the light of the wavelength λ _j is output from the output end 6b of the input / output channel waveguide 6 _j with low loss (j =
1-n).

Next, a specific design example of the arrayed waveguide grating type optical multiplexer / demultiplexer according to the present embodiment will be described.
Here, each of the channel waveguides 4 ₁ of the arrayed waveguide 4
The interval d of 4 _M is 25 μm. The focal length f of the slab waveguide 5 is set to 18.162 nm. The difference ΔL between two adjacent geometrical lengths of the channel waveguides 4 ₁ to 4 _M of the arrayed waveguide section 4 is 106.8 μm. The diffraction order m is set to 100. The effective refractive index n _TE for the TE mode light in the slab waveguide 5 is 1.4510, and the effective refractive index n _TM for the TM mode light is 1.4514.
At this time, the birefringence B is −4 × 10 ⁻⁴ . When the birefringent flat plate 7 is not provided, the input / output channel waveguide 6
The positional shift amount Δz between the TE mode light and the TM mode light incident on _j is calculated to be 21.4 μm.

Therefore, in order to compensate for the displacement Δz, a rutile crystal plate is used as the birefringent flat plate 7, the angle between the c-axis of the rutile crystal plate and the normal is set to 46 degrees, and The thickness is set to 220 μm. In the region where the slab waveguide 5 is formed on the substrate 1, a groove having a width of about 220 μm is formed by dicer processing so as to cross the optical path. Then, the rutile crystal plate is buried in the groove so that the plane where the c-axis and the normal line of the rutile crystal plate extend is parallel to the surface of the substrate 1 and is bonded and fixed with an adhesive.

When an array waveguide diffraction grating type optical multiplexer / demultiplexer was actually manufactured in this manner, the deviation PDλ of the minimum loss peak wavelength when the birefringent flat plate 7 was not provided was 0.
In contrast to 4 nm, by inserting the birefringent flat plate 7 in the middle of the optical path of the slab waveguide 5, the shift amount PDλ of the minimum loss peak wavelength was reduced to about 0.05 nm.
Further, the loss increased by inserting the birefringent flat plate 7 in the middle of the optical path of the slab waveguide 5 was about 0.1 dB or less, which was extremely small. Further, no deterioration of the crosstalk characteristic was observed.

In the above-described manufacturing method, a groove is formed by dicer processing in a region on the substrate 1 where the slab waveguide 5 is formed, and the birefringent flat plate 7 is embedded in the groove. A groove may be formed by etching, and by inserting the birefringent flat plate 7 in the middle of the optical path of the slab waveguide 5, each of the TE mode light and the TM mode light passes through the birefringent flat plate 7. There is a case where a phase difference occurs due to the difference in the optical path length. If this phase difference causes a problem in optical transmission, it is preferable to insert a phase difference compensating plate in the optical path of the slab waveguide 3 or 5. FIG. 4 is a configuration diagram of an arrayed waveguide grating optical multiplexer / demultiplexer according to another embodiment. In the array waveguide diffraction grating type optical multiplexer / demultiplexer shown in this figure, a phase difference compensating plate 8 is inserted in the optical path of the slab waveguide 3. A groove is formed by dicing or etching in a region on the substrate 1 where the slab waveguide 3 is formed, and a phase difference compensating plate 8 is embedded in the groove and fixed by adhesion. , To compensate for a phase difference generated in the birefringent flat plate 7.

[0037]

As described in detail above, the arrayed waveguide grating type optical multiplexer / demultiplexer according to the present invention is provided on a substrate.
A first input / output channel waveguide, a first slab waveguide,
An array waveguide section composed of M channel waveguides, a second slab waveguide, and N second input / output channel waveguides are formed, and in the middle of the optical path of the second slab waveguide. A birefringent flat plate is embedded.

If the effective refractive index differs depending on the polarization state due to the residual stress in each of the M channel waveguides constituting the arrayed waveguide section, if the birefringent flat plate is not provided, the second input / output When light is incident on the first input / output end of the channel waveguide for use, a positional shift occurs due to a difference in polarization state. However, since the birefringent flat plate is provided in the middle of the optical path of the second slab waveguide. , This displacement is compensated. Then, light is efficiently incident on the first input / output end of the second input / output channel waveguide regardless of the polarization state. As described above, the polarization dependence at the time of input to the second input / output channel waveguide is reduced, and the shift amount of the minimum loss peak wavelength is reduced.

Therefore, the arrayed waveguide grating type optical multiplexer / demultiplexer according to the present invention has a small increase in loss due to the insertion of the birefringent flat plate, and can be easily manufactured only by inserting the birefringent flat plate. In addition, when a birefringent flat plate is inserted, a new occupied area is not required on the substrate or separately from the substrate.

Further, when a phase difference compensating plate is buried between the first input / output terminal and the second input / output terminal of any of the first and second slab waveguides, Even if a phase difference occurs due to the difference in the optical path length when the light in each polarization state passes through the birefringent flat plate, the phase difference is compensated because the phase difference compensating flat plate is provided.

The method for manufacturing an arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention is the same as the method for manufacturing an arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention. A groove is formed between the first input / output end and the second input / output end of the wave path, and a birefringent flat plate is embedded and fixed in the groove. Further, a groove is formed between the first input / output terminal and the second input / output terminal of any of the first and second slab waveguides, and a phase difference compensating plate is buried in the groove and fixed by adhesion. I do. With this manufacturing method, the above-described arrayed waveguide grating optical multiplexer / demultiplexer according to the present invention can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an arrayed waveguide grating optical multiplexer / demultiplexer according to an embodiment.

FIG. 2 is an explanatory diagram of a birefringent flat plate in the arrayed waveguide grating optical multiplexer / demultiplexer according to the present embodiment.

FIG. 3 is a diagram illustrating the polarization dependence of the minimum loss peak wavelength in the arrayed waveguide grating optical multiplexer / demultiplexer according to the present embodiment.

FIG. 4 is a configuration diagram of an arrayed waveguide grating optical multiplexer / demultiplexer according to another embodiment.

FIG. 5 is a configuration diagram of a conventional arrayed waveguide diffraction grating type optical multiplexer / demultiplexer.

FIG. 6 is a diagram illustrating light guiding in a slab waveguide of a conventional arrayed waveguide diffraction grating type optical multiplexer / demultiplexer.

FIG. 7 is a diagram illustrating the polarization dependence of the minimum loss peak wavelength in a conventional arrayed waveguide grating optical multiplexer / demultiplexer.

FIG. 8 is a diagram illustrating parameters in an arrayed waveguide grating optical multiplexer / demultiplexer.

[Explanation of symbols]

1 ... substrate, 2 ... first input-output channel waveguide, 3 ... first slab waveguide, 4 ... array waveguide portion, 5 ... second slab waveguide, 6 ₁ to 6 _N ... second Input / output channel waveguides, 7: birefringent flat plate, 8: phase difference compensating flat plate.

Claims (5)

[Claims] 1. An arrayed waveguide grating type optical multiplexer / demultiplexer formed on a substrate for multiplexing / demultiplexing light, the substrate having first and second input / output terminals on the substrate. A first input / output channel waveguide for outputting light to the second input / output terminal when light is input to the first input / output terminal; and a second input / output channel waveguide of the first input / output channel waveguide. A first input / output terminal connected to the input / output terminal and M (M ≧ 2) second input / output terminals that output light when the light is input to the first input / output terminal; One slab waveguide, a first input / output end connected to the M second input / output ends of the first slab waveguide on a one-to-one basis, and an optical input / output terminal connected to the first input / output end. And a second input / output end for outputting the light when the light is inputted, and an arrayed waveguide section comprising M channel waveguides each having a different optical path length by a predetermined length. And M first input / output terminals connected to the second input / output terminals of each of the M channel waveguides of the array waveguide section on a one-to-one basis, and the M first input / output terminals thereof. When light is input to each of the input and output terminals, N (N ≧ 2) second
A second slab waveguide having a first input / output end connected to the N number of second input / output ends of the second slab waveguide; And N second input / output channel waveguides each having a second input / output end for outputting light when light is input to the first input / output end, wherein: A birefringent flat plate is buried between the first input / output terminal and the second input / output terminal of an optical waveguide. 2. The optical multiplexer / demultiplexer according to claim 1, wherein the birefringent flat plate is a rutile crystal plate. 3. The method according to claim 1, wherein a phase difference compensating plate is buried between the first input / output terminal and the second input / output terminal of any one of the first and second slab waveguides. 2. An optical multiplexer / demultiplexer according to claim 1, wherein said optical waveguide is a diffraction grating type optical multiplexer / demultiplexer. 4. A method for manufacturing an arrayed waveguide grating type optical multiplexer / demultiplexer for multiplexing / demultiplexing light formed on a substrate, comprising: a first input / output terminal on the substrate; A first input / output channel waveguide configured to output light to the second input / output terminal when light is input to the first input / output terminal; A first input / output terminal connected to the second input / output terminal, and M (M ≧ 2) second input / output terminals outputting light when the light is input to the first input / output terminal; A first slab waveguide having: a first input / output terminal connected to the M second input / output terminals of the first slab waveguide in a one-to-one correspondence; An array comprising M channel waveguides, each having a second input / output end for outputting light when the light is input to the end, and each having a different optical path length by a predetermined length. A waveguide section; M first input / output ends connected to the second input / output ends of each of the M channel waveguides in the arrayed waveguide section; When light is input to each of the first input / output terminals, N (N ≧ 2) second light
A second slab waveguide having a first input / output end connected to the N second input / output ends of the second slab waveguide; N second input / output channel waveguides each having a second input / output end for outputting light when light is input to the first input / output end; A groove is formed between the first input / output end and the second input / output end of the waveguide, and a birefringent flat plate is buried in the groove and adhesively fixed. How to make a duplexer. 5. A groove is formed between the first input / output terminal and the second input / output terminal of any one of the first and second slab waveguides, and the groove is formed in the groove. 5. The method for manufacturing an arrayed waveguide grating optical multiplexer / demultiplexer according to claim 4, wherein a flat plate is embedded and fixed.