JPH11223736A - Optical wavelength multiplexer/demultiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an light wavelength multiplexer/demultiplexer such that low cross-talk, mass production, and low cost can be attained. SOLUTION: This is a light wavelength multiplexer/demultiplexer constituted of an optical waveguide formed on a plane substrate. One asymmetrical Mach- Zehnder interferometer type light wavelength multiplexer/demultiplexer l and two array waveguide grating type light wavelength multiplexers/demultiplexers 4 and 5 connected with the two outputs of the asymmetrical Mach-Zehnder interferometer type light wavelength multiplexer/demultiplexer 1 are constituted as one basic structure, and at least one set of the basic structure or more are included in this system. Thus, light wavelength multiplexing/demultiplexing is realized with a lower cross-talk than the characteristics of a conventional single array waveguide grating type light wavelength multiplexer/demultiplexer.

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 in the fields of optical communication, optical signal processing, and optical measurement, and more particularly to low crosstalk, mass production, and low cost. It relates to a possible optical wavelength multiplexer / demultiplexer.

[0002]

2. Description of the Related Art Research and development of optical circuits fabricated on a flat substrate such as silicon (Si) or quartz have been promoted as promising practical optical devices in the fields of optical communication, optical information processing, and optical measurement. (Kawachi et al., J. Quantum Electron.
22 (1990) 391.). Among these optical circuits, a circuit having a wavelength multiplexing / demultiplexing function of light has been increasing in importance as the demand for constructing a wavelength division multiplexing optical communication system has increased in recent years. As an optical circuit having an optical wavelength multiplexing / demultiplexing function, a dielectric multilayer filter insertion type [Inoue et al, Electr
on. Lett. 32 (1996) 847.], Asymmetrical Mahazenda interferometer type (hereinafter, MZI type) [Suzuki et al., IEEEJ. Lightwave
Technol. 12 (1994) 790.], grating type [Nishihara et al.,
Optical Integrated Circuit Chapter 4, Ohmsha], Array waveguide grating type (hereinafter, AWG type) [Takahashi et al., IEEEJ. Lightwa
ve Technol. 12 (1994) 989.] has been developed.

[0003]

Among these optical circuits having an optical wavelength multiplexing / demultiplexing function, an MZI type optical wavelength multiplexing / demultiplexing device has a relatively simple structure and a frequency of 10 GHz to 100 GHz.
Wavelength multiplexing / demultiplexing with a narrow channel interval is realized with low loss and low crosstalk. FIG. 6 shows a conventional MZI.
FIG. 1 is a diagram showing a schematic configuration of an example of a type optical wavelength multiplexer / demultiplexer. The MZI type optical wavelength multiplexer / demultiplexer 1 shown in FIG. 6 has two input optical waveguides 11 and two output optical waveguides 12 formed on a substrate 10 and a predetermined length (ΔL). Two different arm optical waveguides (15, 16) are connected by two directional couplers (13, 14) having a coupling ratio of 3 dB.
Further, the MZI type optical wavelength multiplexer / demultiplexer 1 is provided with a thin film heater type thermo-optic phase shifter (17, 18), which can be used to easily adjust a desired optical path length difference. it can.

In order to realize a multi-channel optical wavelength multiplexer / demultiplexer using the MZI type optical wavelength multiplexer / demultiplexer 1, MZI type optical wavelength multiplexer / demultiplexer is required.
The configuration is such that I-type optical wavelength multiplexer / demultiplexers are connected in multiple stages. For example, in order to realize an eight-channel optical wavelength multiplexer / demultiplexer, as shown in FIG. 7, an MZI type optical wavelength multiplexer / demultiplexer 1 having a wavelength demultiplexing characteristic of a frequency interval of 10 GHz and a frequency interval of 20 GHz MZI type optical wavelength multiplexer / demultiplexer (2a, 2b) having the wavelength demultiplexing characteristics described above, and MZI type optical wavelength multiplexer / demultiplexer (3a-3) having the wavelength demultiplexing characteristics at a frequency interval of 40 GHz.
and d) need to be connected in three stages.

This is because each of the MZs constituting the optical wavelength multiplexer / demultiplexer is
It is necessary to adjust the phase error for each I-type optical wavelength multiplexer / demultiplexer (1, 2a, 2b, 3a to 3d), which means that the manufacturing process becomes complicated.

Therefore, a multi-channel optical wavelength multiplexer / demultiplexer composed of MZI type optical wavelength multiplexers / demultiplexers such as 64 and 128 wavelengths is not suitable for mass production. It is difficult to respond to the problem.

[0007] With respect to each wavelength multiplexer / demultiplexer of a dielectric multilayer filter insertion type and a grating type, an optical wavelength multiplexer / demultiplexer exhibiting good characteristics for the number of wavelengths of about 2 to 8 waves is manufactured. There are also examples. However, as in the case of the MZI-type optical wavelength multiplexer / demultiplexer, considering a device compatible with multiple wavelengths such as 32 waves and 64 waves, it is expected that the manufacturing process will be complicated or the device will be enlarged. ,
It seems that mass production at low cost is difficult.

On the other hand, the AWG type optical wavelength multiplexer / demultiplexer is capable of multiplexing / demultiplexing a plurality of wavelengths at a time, and is attracting attention as an important device for constructing a wavelength division multiplexing optical communication system. FIG. 8 is a diagram showing a schematic configuration of an example of a conventional AWG type optical wavelength multiplexer / demultiplexer 4. As shown in FIG. The AWG type optical wavelength multiplexer / demultiplexer 4 shown in FIG. 8 includes an input channel optical waveguide 21, an output channel optical waveguide 22, a channel optical waveguide array (array optical waveguide grating) 23 formed on the substrate 10, and Input channel optical waveguide 21 and channel optical waveguide array 2
3 and an output fan-shaped slab optical waveguide 25 connecting the channel optical waveguide array 23 and the output channel optical waveguide 22. The channel optical waveguide array 23 is configured such that the length of each optical waveguide is sequentially increased by a predetermined optical waveguide length difference (ΔL).

The wavelength interval (Δλ) of such an AWG type optical wavelength multiplexer / demultiplexer includes a pitch (d) of the channel optical waveguide array 23, an optical waveguide length difference (ΔL), an effective refractive index (n _c ), and a group. Refractive index ( _ng ), the input channel optical waveguide 2
1 and the optical waveguide interval (Δx) in the output channel optical waveguide 22, the radius of curvature (focal length) (f) of the slab optical waveguides (24, 25), the effective refractive index ( _ns ), and the like. be able to. The frequency of light obtained from the optical waveguide at the center of the output channel optical waveguide 22 (having a diffraction angle of 0 degree) is called a center frequency (fo). As an order, fo
= MC / of more information (n _c · ΔL) in determined (AWG type optical wavelength demultiplexer, T.Takahashi, et al., J.Lightwave T
echnol. 12, p. 989, 1994. ).

However, the A which has been developed
The WG type optical wavelength multiplexer / demultiplexer has a tendency that crosstalk increases as the wavelength separation (Δλ) decreases. For example, crosstalk of an AWG type optical wavelength multiplexer / demultiplexer having a demultiplexing interval of 100 GHz (approximately 0.8 nm in a wavelength band of 1.55 μm) (crosstalk at a wavelength separated by a demultiplexing wavelength interval from the center wavelength of the transmission band). Talk) has reached about −40 dB, while the frequency is 10 GHz (wavelength 1.55 μm).
The crosstalk of an AWG type optical wavelength multiplexer / demultiplexer having a demultiplexing interval of about 0.08 nm in the m-band is only about -15 dB [Takahashi et al., Data of Optical Switching Technology Research Group (1992)
p. 41]. Fig. 9 shows the channel spacing dependence of crosstalk in the AWG type optical wavelength multiplexer / demultiplexer developed so far.
Shown in

It is considered that these crosstalks are caused by an error in the optical path length of each of a large number of optical waveguides in the channel optical waveguide array (array optical waveguide grating) 23. In order to correct this optical path length error, a method of providing a thin film heater type thermo-optic phase shifter in each of a large number of arrayed optical waveguides and adjusting the phase error [Yamada et al., IEICE General Conference C-253 (1995) )] And a method of inserting a phase compensating plate [Japanese Patent Application No. 9-182651]. However, the method of correcting the phase error of the channel optical waveguide array is a time-consuming step of correcting each of tens of optical waveguides in the channel optical waveguide array, and mass production and cost reduction are required. There was a problem that it was difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an optical wavelength multiplexer / demultiplexer with low crosstalk, mass production, and cost reduction. It is to provide a technology that makes it possible. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0013]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, the present invention relates to an optical wavelength multiplexer / demultiplexer constituted by an optical waveguide formed on a plane substrate, wherein the optical wavelength multiplexer / demultiplexer comprises one asymmetrical Mahachender interferometer type optical wavelength multiplexer / demultiplexer. And two or more arrayed waveguide grating type optical wavelength multiplexer / demultiplexers respectively connected to two outputs of the optical wavelength multiplexer / demultiplexer are included as one basic structure, and one or more sets of the basic structures are included. I do.

Further, according to the present invention, the FSR of the optical wavelength multiplexer / demultiplexer according to the asymmetrical Mahach-Zehnder interferometer is N [GHz] (N
Is a real number), and the wavelength multiplexing / demultiplexing interval of the arrayed waveguide grating type optical wavelength multiplexing / demultiplexing device is N [GHz].

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.

[First Embodiment] FIG. 1 is a diagram showing a schematic configuration of an optical wavelength multiplexer / demultiplexer according to a first embodiment of the present invention. As shown in the figure, the optical wavelength multiplexer / demultiplexer of the present embodiment has
MZI type optical wavelength multiplexer / demultiplexer 1 and two AWs respectively connected to two outputs of the MZI type optical wavelength multiplexer / demultiplexer.
And a G-type optical wavelength multiplexer / demultiplexer (4, 5). This M
The ZI type optical wavelength multiplexer / demultiplexer 1 and the AWG type optical wavelength multiplexer / demultiplexer (4, 5) are arranged on the substrate 10, respectively.

This MZI type optical wavelength multiplexer / demultiplexer 1 has a wavelength demultiplexing characteristic with a frequency interval of 10 GHz. In FIG. 1, reference numerals 13 and 14 denote directional couplers having a coupling ratio of 3 dB. , 16 indicate arm optical waveguides connecting the directional couplers (13, 14). This arm optical waveguide (15, 1)
6) has an optical path length of 10 mm, and has an arm optical waveguide (1).
On the upper surfaces of the cladding layers (5, 16), thin-film heater-type thermo-optic phase shifters (17, 18) are provided, respectively, so that the optical path length can be finely adjusted.

The AWG type optical wavelength multiplexer / demultiplexer 4 has a wavelength demultiplexing characteristic at a frequency interval of 20 GHz, and the AWG type optical wavelength multiplexer / demultiplexer 4 includes an input channel optical waveguide 21 and an output channel optical waveguide. 22, a channel optical waveguide array 23, the input channel optical waveguide 21 and the channel optical waveguide array 2
3 and an output fan-shaped slab optical waveguide 25 connecting the channel optical waveguide array 23 and the output channel optical waveguide 22. The basic structure of the AWG type optical wavelength multiplexer / demultiplexer 5 is the same as that of the AWG type optical wavelength multiplexer / demultiplexer 4. Where AWG
Center wavelength (f ₀₁ ) of the optical wavelength multiplexer / demultiplexer 4 is 19310
At 0 GHz, the center frequency (f ₀₂ ) of the AWG type optical wavelength multiplexer / demultiplexer 5 is set to 193110 GHz corresponding to the demultiplexing interval of 10 GHz of the MZI type optical wavelength multiplexer / demultiplexer 1 at the preceding stage. Also, the output port 26 of the AWG-type optical wavelength multiplexer / demultiplexer 4,
In addition, the output ports 27 of the AWG-type optical wavelength multiplexer / demultiplexer 5 are arranged with optical waveguides arranged at intervals of 250 μm in the same plane so that connection with a fiber array or the like can be easily performed.

The optical wavelength multiplexer / demultiplexer according to the present embodiment is manufactured by the following method. First, by flame hydrolysis deposition on a silicon (Si) substrate by depositing a lower cladding layer mainly composed of silicon dioxide (SiO _2), then, the silicon dioxide was added germanium dioxide (GeO ₂₎ as the dopant (SiO ₂ After the core layer mainly composed of (1) and (2) is deposited, the glass is transparently vitrified in an electric furnace. Next, an optical waveguide portion is formed by etching, and silicon dioxide (Si
An upper cladding layer mainly composed of O ₂ ) is deposited. Finally, the thin film heater type thermo-optic phase shifter (17, 1
8) was formed on the upper cladding layer. The size of the core layer of the optical waveguide was 7 μm × 7 μm, and the relative refractive index difference Δ between the core layer and the cladding layer was 0.75%.

Hereinafter, the operation principle of the optical wavelength multiplexer / demultiplexer according to the present embodiment will be described. For example, the FSR (Free Spectral Range) of the MZI type optical wavelength multiplexer / demultiplexer 1 is set to N (GH
z), the frequency and the output of f, f ± N, f ± 2N... from one of the two output optical waveguides 12
From the other side, the frequency is f ± (1/2) N, f ± (3 /
2) N is obtained. This output optical waveguide 12
Have the same demultiplexing interval N (GHz), and the center frequencies (fo) are f, f + (1 /
2) Connect N AWG type optical wavelength multiplexer / demultiplexers (4, 5) respectively. Therefore, in the MZI type optical wavelength multiplexer / demultiplexer 1, the frequency multiplexed optical signal having the frequency interval N / 2 (GHz) is N / 2 (GHz) and the frequency is shifted by N / 2 (GHz). The two signal light beams are then input to two AWG type optical wavelength division multiplexers (4, 5) whose center frequencies are different from each other by N / 2 (GHz). You. As a result, the sum of the two AWG-type optical wavelength multiplexer / demultiplexers (4, 5) is calculated assuming that the crosstalk of the AWG-type optical wavelength multiplexer / demultiplexer with the separation interval N (GHz) is maintained. An output of N / 2 (GHz) is obtained. That is, according to the optical wavelength multiplexer / demultiplexer of the present embodiment, in order to demultiplex an optical signal having a frequency interval of N / 2 (GHz), an AWG type optical wavelength multiplexer / demultiplexer having a wavelength separation interval of N (GHz) is used. Multiplexing / demultiplexing interval N / 2
The crosstalk can be remarkably improved as compared with the case where the (WG) AWG type optical wavelength multiplexer / demultiplexer is used alone.

Further, the above principle will be specifically supplemented by taking as an example a case where an optical signal multiplexed at 10 GHz is demultiplexed. First, the optical signal multiplexed at 10 GHz is FS
In the MZI type optical wavelength multiplexer / demultiplexer 1 in which R is 20 GHz,
The signal light flux is split into two at a frequency interval of 20 GHz.
Each signal beam has a demultiplexing interval of 20 GHz.
Are passed through the two AWG type optical wavelength multiplexer / demultiplexers (4, 5) to be demultiplexed and output. As a result, in the entire optical wavelength multiplexer / demultiplexer of the present embodiment, the frequency interval is 10 GHz.
The optical wavelength demultiplexing of z can be realized with the same crosstalk as that of a conventional AWG type optical wavelength demultiplexer having an optical wavelength demultiplexing / demultiplexing characteristic of 20 GHz. FIG. 2 is a graph showing optical wavelength demultiplexing characteristics of the optical wavelength multiplexer / demultiplexer according to the present embodiment. In the figure, output lights from two AWG type optical wavelength multiplexer / demultiplexers (4, 5) are superimposed and displayed, and light indicated by A in the figure is AW light.
The light indicated as B from the G-type optical wavelength multiplexer / demultiplexer 4 is AWG
3 shows output light from the type optical wavelength multiplexer / demultiplexer 5. In addition,
The light demultiplexed by the optical wavelength multiplexer / demultiplexer according to the present embodiment covers a total of 128 waves. In FIG. 2, in particular, the light having a wavelength of about 8 around the center frequency (f ₀₁ ) (193100 FHz, A5 in FIG. 2).
The wave and the center frequency (f ₀₂ ) (193110 FHz, FIG. 2)
B5) shows the optical wavelength demultiplexing characteristics of 16 waves before and after 8 waves in total. As can be seen from the graph of FIG.
The optical wavelength demultiplexer with a frequency interval of 10 GHz, which was realized only by the -14 dB crosstalk in the WG type optical wavelength multiplexer / demultiplexer alone, is -2 in the optical wavelength multiplexer / demultiplexer of the present embodiment.
The crosstalk is improved to 5 dB.

[Second Embodiment] FIG. 3 is a diagram showing a schematic configuration of an optical wavelength multiplexer / demultiplexer according to a second embodiment of the present invention. As shown in FIG. 1, the optical wavelength multiplexer / demultiplexer according to the present embodiment includes an MZI type optical wavelength multiplexer / demultiplexer 1 having a wavelength demultiplexing characteristic with a frequency interval of 10 GHz and a wavelength demultiplexer with a frequency interval of 20 GHz. An MZI type optical wavelength multiplexer / demultiplexer (2a, 2b)
Further, two 64 × 64 channel AWG type optical wavelength multiplexer / demultiplexers (4 to 7) having wavelength demultiplexing characteristics with a frequency interval of 40 GHz constitute a two-layer structure of an upper layer 8 and a lower layer 9. It is formed.

The MZI type optical wavelength multiplexer / demultiplexer 1 having a wavelength demultiplexing characteristic at a frequency interval of 10 GHz comprises an optical waveguide 31 on the upper layer 8 and an optical waveguide 32 on the lower layer 9. A directional coupler having a coupling ratio of 3 dB is formed at the upper and lower portions. Reference numerals 15 and 16 denote arm optical waveguides for connecting the directional couplers (13 and 14). The arm optical waveguides (15 and 16) have an optical path length difference of 10 mm. Further, on the upper surface of the intermediate cladding layer on the arm optical waveguide 15, a thin film heater type thermo-optic phase shifter 1 is provided.
7. On the upper cladding layer on the arm optical waveguide 16, a thin film heater type thermo-optic phase shifter 18 is provided so that the optical path length can be finely adjusted. MZ having wavelength demultiplexing characteristics at a frequency interval of 20 GHz on the upper layer 8
The I-type optical wavelength multiplexer / demultiplexer 2a and the MZI-type optical wavelength multiplexer / demultiplexer 2b having a wavelength demultiplexing characteristic at a frequency interval of 20 GHz on the lower layer 9 have the above-mentioned frequency interval of 10 GHz. Is the same as that of the MZI type optical wavelength multiplexer / demultiplexer 1 having the wavelength demultiplexing characteristic of FIG.
mm.

In an AWG type optical wavelength multiplexer / demultiplexer (4 to 7) having a wavelength demultiplexing characteristic with a frequency interval of 40 GHz, an AWG
The optical wavelength multiplexer / demultiplexer 4 and the AWG optical wavelength multiplexer / demultiplexer 5 are arranged in the upper layer 8, and the AWG optical wavelength multiplexer / demultiplexer 6 and the AWG optical wavelength multiplexer / demultiplexer 7 are located in the lower layer 9. Be placed. These AW
The basic configuration of the G-type optical wavelength multiplexer / demultiplexer (4 to 7) is almost the same. If the AWG-type optical wavelength multiplexer / demultiplexer 4 is taken as an example, the input channel optical waveguide 21, the output channel optical waveguide 22,
A channel optical waveguide array 23, an input-side fan-shaped slab optical waveguide 24 connecting the input channel optical waveguide 21 and the channel optical waveguide array 23, and connecting the channel optical waveguide array 23 and the output channel optical waveguide 22. The output side fan-shaped slab optical waveguide 25 is configured. Here, the center frequency (f _{01 to} f ₀₄ ) of the AWG type optical wavelength multiplexer / demultiplexer (4 to 7) is equal to the MZI type optical wavelength multiplexer / demultiplexer (2
a, 2b) corresponding to a demultiplexing interval of 20 GHz,
90 GHz, 193100 GHz, 193110 GH
z is set to 193120 GHz. As shown in FIG. 4, the exit ports (26 to 29) of the AWG type optical wavelength multiplexer / demultiplexer (4 to 7) are formed to have a certain unity.
Connection to a fiber array or the like can be easily performed.

The optical wavelength multiplexer / demultiplexer according to this embodiment is manufactured by the following method. First, by flame hydrolysis deposition on a silicon (Si) substrate by depositing a lower cladding layer mainly composed of silicon dioxide (SiO _2), then, the silicon dioxide was added germanium dioxide (GeO ₂₎ as the dopant (SiO ₂ After the core layer mainly composed of (1) and (2) is deposited, the glass is transparently vitrified in an electric furnace. Next, etching is performed to form a lower optical waveguide portion, and an intermediate cladding layer containing silicon dioxide (SiO ₂ ) as a main component is deposited again.
A thin film heater type thermo-optic phase shifter is formed on the upper part. Further, a core layer mainly composed of silicon dioxide (SiO ₂ ) doped with germanium dioxide (GeO ₂ ) as a dopant is deposited and etched to form an upper optical waveguide portion, and again silicon dioxide (SiO ₂ ) is mainly used. An upper clad layer as a component was deposited. Finally, a thin film heater type thermo-optic phase shifter is formed on the upper cladding layer. The size of the core layer of the optical waveguide is 7 μm × 7 μm.
m, the relative refractive index difference Δ between the core layer and the cladding layer is 0.75
(For such a multilayer optical waveguide, see Suzuki et al., Proceedings of the 1992 IEICE Autumn Conference 4-
See 25).

The operation principle of the optical wavelength multiplexer / demultiplexer according to this embodiment will be described below. In this embodiment, in order to further reduce crosstalk, one MZI optical wavelength multiplexer / demultiplexer 1 having an FSR of 20 GHz and an FSR of 40 GHz
And two MZI type optical wavelength multiplexer / demultiplexers (2a, 2b) are connected in multiple stages, and the optical signal multiplexed at 10 GHz is wavelength-demultiplexed into four signal light beams at a frequency interval of 40 GHz (Takato etal., IEEEJ.SelectedAreas in Commun.Vol.8
(1990) 1120.). Thereafter, each signal light beam is divided into four AWG type optical wavelength multiplexer / demultiplexers (4
７7) Therefore, according to the present embodiment, in the entire optical wavelength multiplexer / demultiplexer, the wavelength demultiplexer having a frequency interval of 10 GHz is replaced with the conventional AWG type optical wavelength multiplexer / demultiplexer having the optical wavelength multiplexer / demultiplexer having a frequency interval of 40 GHz. It can be realized with the same crosstalk as a wave device.

FIG. 5 is a graph showing the optical wavelength demultiplexing characteristics of the optical wavelength multiplexer / demultiplexer according to the present embodiment. In the figure, the output light from the four AWG type optical wavelength multiplexer / demultiplexers (4 to 7) is superimposed and displayed, and the light indicated by A in the figure is the AWG type optical wavelength multiplexer / demultiplexer. The light indicated as B from the optical device 4 is from the AWG type optical wavelength multiplexer / demultiplexer 5, the light indicated as C is from the AWG type optical wavelength multiplexer / demultiplexer 6, and the light indicated as D is an AWG type light. The output light from the wavelength multiplexer / demultiplexer 7 is shown. The light demultiplexed by the optical wavelength multiplexer / demultiplexer according to the present embodiment has a total of 256
In FIG. 5, the center frequency (f ₀₁ ) (19
5A, the three waves around A3) in FIG. 5, the four waves around the center frequency (f ₀₂ ) (193100 FHz, B3 in FIG. 5), and the four waves around the center frequency (f ₀₃ ) (193110 FHz, FIG. 5).
C3), four waves before and after and a center frequency (f ₀₄ ) (1931)
The optical wavelength demultiplexing characteristics of a total of 16 waves at 20 FHz and four waves before and after D3) in FIG. 5 are shown. As can be seen from the graph of FIG. 5, the conventional AWG type optical wavelength multiplexer / demultiplexer alone has −14d.
The optical wavelength demultiplexing at a frequency interval of 10 GHz, which was realized only by the B crosstalk, is improved to -35 dB crosstalk in the optical wavelength multiplexer / demultiplexer of the present embodiment.

As described above, the invention made by the present inventor is:
Although a specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the invention.

[0029]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. (1) According to the present invention, one asymmetrical Maha-Zehnder interferometer type optical wavelength multiplexer / demultiplexer is connected to two outputs of the asymmetrical Maha-Zehnder interferometer type optical wavelength multiplexer / demultiplexer.
And a plurality of array waveguide grating type optical wavelength multiplexer / demultiplexers as a basic structure, and include at least one of the basic structures. Optical wavelength multiplexing / demultiplexing can be realized with low crosstalk. (2) According to the present invention, in the arrayed optical waveguide grating of the arrayed waveguide grating type optical wavelength multiplexer / demultiplexer, it is possible to avoid the phase error correction for each one, thereby realizing mass production and cost reduction. Can be achieved. (3) According to the present invention, since the optical waveguides constituting the optical wavelength multiplexer / demultiplexer are laminated in two or more layers, the optical wavelength multiplexer / demultiplexer can be made compact.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an optical wavelength multiplexer / demultiplexer according to a first embodiment of the present invention.

FIG. 2 is a graph showing optical wavelength demultiplexing characteristics of the optical wavelength multiplexer / demultiplexer according to the first embodiment.

FIG. 3 is a diagram illustrating a schematic configuration of an optical wavelength multiplexer / demultiplexer according to a second embodiment of the present invention.

FIG. 4 is a diagram showing an optical waveguide arrangement of an emission port in the second embodiment.

FIG. 5 is a graph showing optical wavelength demultiplexing characteristics of the optical wavelength multiplexer / demultiplexer according to the second embodiment.

FIG. 6 is a diagram showing a schematic configuration of an example of a conventional MZI type optical wavelength multiplexer / demultiplexer.

FIG. 7 is a diagram showing a schematic configuration of an example of an optical wavelength multiplexer / demultiplexer in which MZI type optical wavelength multiplexer / demultiplexers are connected in multiple stages to form a multi-channel.

FIG. 8 is a diagram showing a schematic configuration of an example of a conventional AWG type optical wavelength multiplexer / demultiplexer.

FIG. 9 is a graph showing the relationship between channel spacing and crosstalk in a conventional AWG type optical wavelength multiplexer / demultiplexer.

[Explanation of symbols]

1, 2a, 2b, 3a to 3d: asymmetrical Maha-Zehnder interferometer type optical wavelength multiplexer / demultiplexer, 4, 5, 6, 7 ... array waveguide grating type optical wavelength multiplexer / demultiplexer, 8: upper layer, 9: lower layer, Reference numeral 10: substrate, 11: input optical waveguide, 12: output optical waveguide, 1
3, 14 ... directional coupler, 15, 16 ... arm optical waveguide, 17, 18 ... thin film heater type thermo-optic phase shifter, 2
DESCRIPTION OF SYMBOLS 1 ... Channel optical waveguide for input, 22 ... Channel optical waveguide for output, 23 ... Channel optical waveguide array, 24 ... Slab optical waveguide on the input side, 25 ... Slab optical waveguide on the output side, 26, 27, 28, 29 ... Outgoing ports, 31, 32 ... Optical waveguides.

Claims (5)

[Claims] 1. An optical wavelength multiplexer / demultiplexer configured by an optical waveguide formed on a plane substrate, comprising: one asymmetrical Mahazenda interferometer type optical wavelength multiplexer / demultiplexer;
The above-mentioned basic structure is composed of two or more sets of two basic optical waveguide multiplexer / demultiplexers each connected to two outputs of the asymmetrical Maha-Zehnder interferometer type optical wavelength multiplexer / demultiplexer. An optical wavelength multiplexer / demultiplexer, comprising: 2. The FSR of the asymmetrical Maha-Zehnder interferometer type optical wavelength multiplexer / demultiplexer is N [GHz] (N is a real number), and the wavelength coupling / demultiplexing interval of the arrayed waveguide grating type optical wavelength multiplexer / demultiplexer is N.
The optical wavelength multiplexer / demultiplexer according to claim 1, wherein the frequency is [GHz]. 3. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein the optical waveguide is made of a material mainly composed of quartz. 4. The optical waveguide according to claim 1, wherein at least a part of the optical waveguide is formed by laminating two or more layers.
The optical wavelength multiplexer / demultiplexer according to claim 3. 5. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein at least one optical waveguide and an adjacent optical waveguide are formed on the same plane at an input / output portion of the optical wavelength multiplexer / demultiplexer. 5. The optical wavelength multiplexer / demultiplexer according to any one of 4.