JP2002082240A - Optical multiplexer/demultiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique by which a polarized wave/wavelength multiple transmission circuit is composed of a small number of devices. SOLUTION: In the case of manufacturing an arrayed waveguide grating type optical multiplexer/demultiplexer wherein slab waveguides 19 and 20 are provided in each of the input side and the output side of an array waveguide 18 in which plural waveguides 17 having different iengths are juxtaposed within a clad layer formed on a substrate, an input waveguide 21 is provided in the input side of the input side slab waveguide 19, and plural number of output waveguides 22 are provided in the output side of the output side slab waveguide 20, the optical multiplexer/demultiplexer, wherein multiplexed light of plural light having different wavelengths is inputted into the input waveguide 21, light demultiplexed every wavelength and every polarized wave is outputted from each of the output waveguides 22 and inversely an operation of outputting muitiplexed light is also possible, is composed by forming the waveguide large in the difference between effective refractive indexes of two polarized waves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrayed waveguide grating type optical multiplexer / demultiplexer used in the field of optical communication, which can simultaneously separate wavelength and polarization.

[0002]

2. Description of the Related Art In an optical communication system, in order to transmit a large amount of information, a wavelength multiplex transmission system has been proposed in which light having different wavelengths is multiplexed and transmitted. In addition, since light is composed of two orthogonal polarizations, a polarization / wavelength multiplexing transmission system in which light of different wavelengths is multiplexed and transmitted, and output when separated for each wavelength and for each polarization Has also been proposed. One polarization is called TE polarization, and the other polarization is called TM polarization.

FIG. 14 shows an example of a block diagram of a conventional polarization / wavelength multiplex transmission circuit. In this circuit, when multiplexed light of four wavelengths λ1, λ2, λ3, and λ4 is input to the input side optical fiber 1 located on the left side in the drawing, this light is input to the input port 2a of the polarization splitter 2. Then, the polarization splitter 2 separates each polarization, and outputs the TE-polarized multiplexed light of four wavelengths and the TM-polarized multiplexed light of four wavelengths from the output ports 2b and 2c, respectively. Next, the TE-polarized multiplexed light is input to the input port 3a of the optical multiplexer / demultiplexer 3 via the optical fiber 1 connected to the output port 2b, separated by the optical multiplexer / demultiplexer 3 for each wavelength, and output. Each of the optical fibers 1... Connected to the ports 3b, 3c, 3d, 3e has a TE of wavelength λ1, λ2, λ3, λ4.
Polarization is output. On the other hand, the multiplexed light of the TM polarization similarly enters the input port 4a of the optical multiplexer / demultiplexer 4 via the optical fiber 1 connected to the output port 2c, and is separated for each wavelength by the optical multiplexer / demultiplexer 4. , Output ports 4b, 4c, 4d, 4e
From each of the optical fibers 1.
The TM polarizations of λ2, λ3, and λ4 are output. As a result, 4
The multiplexed light of the three wavelengths can be distributed to a total of eight lights for each wavelength and for each polarization.

[0004]

As described above, in the conventional polarization / wavelength multiplexing transmission circuit, one polarization splitter for separating polarization and two optical multiplexers / demultiplexers for separating lights having different wavelengths are provided. Was needed. However, as the number of devices that make up the circuit increases, space efficiency decreases,
Since the loss increases, there has been a demand for a technology capable of configuring a polarization / wavelength multiplex transmission circuit with a small number of devices. Specifically, a device that can simultaneously perform polarization separation and wavelength separation has been desired.

On the other hand, as an optical multiplexer / demultiplexer, an arrayed waveguide grating type optical multiplexer / demultiplexer is often used because of its high wavelength separation performance. FIG. 15 shows an example of an arrayed waveguide grating type optical multiplexer / demultiplexer. A plate-shaped cladding layer 6 made of quartz glass is provided on a silicon substrate 5. An arrayed waveguide 8 is formed by arranging waveguides 7, 7,... Made of silica-based glass substantially in parallel and in a U-shape. The lengths of the waveguides 7, 7,... Constituting the arrayed waveguide 8 are different from each other by ΔL.

[0006] Slab waveguides 9 and 10 are provided on the input side and the output side at both ends of the arrayed waveguide 8, respectively. On the input side of the slab waveguide 9, a plurality of input waveguides 11, 11... Are arranged in parallel. On the other hand, a plurality of output waveguides 12 are arranged in parallel on the output side of the slab waveguide 10. Each of the waveguides 7 to 12 is formed of a material having a higher refractive index than the cladding layer 6 located therearound in order to guide light.

[0007] Then, one of the input waveguides 11
When multiplexed light of a plurality of lights having different wavelengths is input, the multiplexed light is distributed to the plurality of waveguides 7, 7... .. Are guided, and an optical path length difference occurs due to ΔL. Then, these lights interfere with each other in the slab waveguide 10 on the output side, the wavelength is selected, and the output is output from each of the output waveguides 12, 12,.

Incidentally, the arrayed waveguide grating type optical multiplexer / demultiplexer is an optical component using a substrate type waveguide, and as it is, the refractive index differs depending on the polarization (has a refractive index anisotropy). There is wave dependence. As described above, a substrate-type waveguide is generally formed by forming a waveguide and a cladding layer made of silica-based glass on a silicon substrate, and therefore, is manufactured by a difference in thermal expansion coefficient between silicon and silica-based glass. Sometimes, during the process of cooling the cladding layer and the waveguide from a high temperature, residual stress occurs in the waveguide, and the residual stress imparts polarization dependence. Therefore, as it is, even if the slab waveguide 1 has the same wavelength,
The condensing position for each polarization at the output end of 0 is different.

Since this characteristic is inconvenient when separating wavelengths, conventionally, a half-wave plate 13 is inserted near the center of the arrayed waveguide 8 as shown in FIG. are doing. Or the output side slab waveguide 1
The input ends of the zero output waveguides 12, 12,... Are set so as to be at the center of the two polarized light condensing positions constituting the light of the wavelength distributed to the respective output waveguides 12. A method of outputting these polarized waves from one output waveguide 12 is used. On the other hand, proposals have been made to use an arrayed waveguide grating type optical multiplexer / demultiplexer as a polarization beam splitter utilizing this polarization dependence. However, an arrayed waveguide grating type optical multiplexer / demultiplexer that simultaneously separates wavelength and polarization has not been proposed yet.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a technique capable of configuring a polarization / wavelength multiplex transmission circuit with a small number of devices. Specifically, it is an object of the present invention to provide an optical multiplexer / demultiplexer capable of simultaneously performing wavelength separation and polarization separation. It is still another object of the present invention to provide an arrayed waveguide grating type optical multiplexer / demultiplexer capable of simultaneously performing wavelength separation and polarization separation.

[0011]

According to a first aspect of the present invention, there is provided an optical multiplexer / demultiplexer comprising: an arrayed waveguide in which a plurality of waveguides having different lengths are arranged in parallel; First and second slab waveguides provided at both ends of the waveguide, input / output waveguides provided outside the first slab waveguide, and outside the second slab waveguide And a plurality of input / output waveguides provided in the cladding layer.
A grating type optical multiplexer / demultiplexer, wherein when a multiplexed light of a plurality of lights having different wavelengths is input to an input / output waveguide provided outside the first slab waveguide, the second slab waveguide is provided. An optical multiplexer / demultiplexer, which outputs light separated for each wavelength and for each polarization from each of a plurality of input / output waveguides provided outside a wave path. Second
In the optical multiplexer / demultiplexer according to the first aspect, one end of the second slab waveguide and the other end of the other side may be arranged for each wavelength at an end on the side of the plurality of input / output waveguides. An optical multiplexer / demultiplexer characterized by different wave focusing positions. According to a third aspect of the present invention, there is provided an optical multiplexer / demultiplexer according to the first or second aspect, wherein the birefringence of the arrayed waveguide is utilized. 4th
In the optical multiplexer / demultiplexer according to any one of the first to third inventions, the cladding layer and the waveguide formed inside the cladding layer are made of plastic. . A fifth invention is an optical multiplexer / demultiplexer according to the fourth invention, wherein the plastic is a fluorinated polyimide. A sixth invention is an optical multiplexer / demultiplexer according to any one of the first to fifth inventions, wherein the cladding layer is provided on a substrate. A seventh invention is the optical multiplexer / demultiplexer according to any one of the first to sixth inventions, wherein, in a wavelength band used by the optical multiplexer / demultiplexer, the effective refractive index of one polarized wave of the array waveguide and the array An optical multiplexer / demultiplexer characterized in that the difference from the effective refractive index of the other polarization of the waveguide is 0.0004 or more. An eighth aspect of the present invention is the optical multiplexer / demultiplexer according to any one of the first to seventh aspects, wherein one or both of polarization and wavelength are input to each of the plurality of input / output waveguides, An optical multiplexer / demultiplexer characterized in that these lights are multiplexed and output from an input / output waveguide provided on the first slab waveguide side.

[0012]

FIG. 1 is a plan view showing an example of the structure of an arrayed waveguide grating type optical multiplexer / demultiplexer according to the present invention. In FIG. 1, a substrate and a cladding layer, which will be described later, are not shown for convenience of explanation. FIG. 2 is a sectional view taken along line AA shown in FIG. This optical multiplexer / demultiplexer has a waveguide formed in a plate-shaped cladding layer 16 formed on a substrate 15 such as a silicon substrate. The waveguide has the following configuration. First, as shown in FIG. 1, an arrayed waveguide 18 in which a plurality of waveguides 17, 17... Are arranged substantially in parallel and in a U-shape is formed at the center. The lengths of these adjacent waveguides 17, 17 are different by ΔL. The number of waveguides 17, 17,... Is appropriately designed. The slab waveguide (first slab waveguide) 19 and the slab waveguide (second slab waveguide) are provided at both ends of the array waveguide 18 at the input side and the output side, respectively, when the light is demultiplexed. (Wave path) 20 is provided. Here, the input side and the output side are used for splitting light. When multiplexing light, the input side and the output side of the array waveguide 18 are reversed. Hereinafter, for the sake of convenience, description will be given along the operation at the time of demultiplexing. The slab waveguide 19 on the input side is substantially rectangular. The two opposing short sides 19c and 19d forming the input end 19a and the output end 19b of the slab waveguide 19 are formed in a bow shape protruding outward. The output side slab waveguide 20 has the same shape as the slab waveguide 19.

On the input side of the slab waveguide 19, one input waveguide (input waveguide) 21 is provided. On the other hand, a plurality of output waveguides (output waveguides) 22 extend from the output side of the slab waveguide 20. The input waveguide 21 corresponds to the above-mentioned “input / output waveguide provided outside the first slab waveguide”. The output waveguides 22, 22,... Correspond to the above-described “a plurality of input / output waveguides provided outside the second slab waveguide”. That is, “outside” here means the opposite side of the arrayed waveguide 18. The number of output waveguides 22, 22,.
Usually, the number is twice the number of wavelengths to be separated, that is, the number of polarizations to be output. The cross-sectional shape of each of the waveguides 17 to 22 is not particularly limited, but is, for example, substantially rectangular as shown in FIG. Each of the waveguides 17 to 22 is formed of a material having a higher refractive index than that of the cladding layer 16 located therearound in order to guide light. In addition, each of the waveguides 17 to
22 are usually formed from the same material and have the same refractive index.

The cladding layer 16 and each of the waveguides 17 to 22
Is made of a transparent material. As the transparent material, a transparent plastic is preferably used. Light of one wavelength is composed of TE polarization and TM polarization. A waveguide using plastic has a large difference in the refractive index between the TE polarized light and the TM polarized light, and is therefore suitable for use in separating polarized light.
Note that, as described above, the refractive index (effective refractive index) of TE polarization and TM
The difference between the refractive index of the polarized wave (effective refractive index) is called birefringence. In the present invention, the birefringence of the array waveguide 18 is used. As the plastic, for example, silicone resin, polyimide resin such as fluorinated polyimide, methacrylic resin such as fluorinated methacrylate, and the like are used. Among them, a polyimide resin is preferable because the difference in refractive index between TE polarized light and TM polarized light is large, and it is easy to adjust the difference in refractive index depending on the combination of monomers used. Polyimide is preferred.

Specifically, as a preferable fluorinated polyimide, a copolymer of 6FDA / TFDB represented by the following [Chemical Formula 1] and 6FDA / ODA represented by the following [Chemical Formula 2] can be exemplified. .

Embedded image

Embedded image

FIG. 3A shows 6FDA in this copolymer.
3 shows the relationship between the ratio of / TFDB and the refractive index of the copolymer. In the figure, n _TE is the refractive index of TE polarization, and n _TM is T
This is the refractive index of M polarized light. As is clear from this graph, the refractive index can be changed by changing the composition of the copolymer. In addition, there is always a difference in the refractive index between the TE polarized light and the TM polarized light, indicating that this copolymer is a material having a large birefringence (refractive index anisotropy) ^{* 1} . Also, 6FDA / TF represented by the above [Chemical Formula 1]
Copolymers of DB and PMDA / TFDB represented by the following [Formula 3] can also be exemplified.

Embedded image FIG. 3B shows the relationship between the ratio of 6FDA / TFDB in the copolymer and the refractive index of the copolymer. The upper graph shows the refractive index of each polarization, and the lower graph shows the difference in the refractive index of each polarization (birefringence).
It can be seen that the difference in refractive index can be changed by changing the ratio of 6FDA / TFDB ^{* 2} . * 1: JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 16, N
O, 16 JUNE 1998, Kobayashi et, al., "Fluorinated Po
lyimide Waveguides with Low Polarization-Dependent
Lossand Their Applications to Thermooptic Switche
s "* 2: Macromolecules, 1994, 27, Tohru Matsuura et.
al., "Polyimides Derived from 2,2'-Bis (trifluorom
ethyl) -4,4'-diaminobiphenyl. 4. Optical Properties
of Fluorinated Polyimides for Optoelectronic Comp
onents "

When the cladding layer and each of the waveguides 17 to 22 are formed of plastic, this arrayed waveguide grating type optical multiplexer / demultiplexer can be manufactured, for example, as follows. That is, a lower cladding layer corresponding to the thickness of the cladding layer below the waveguides 17 to 22 is formed on the upper surface of the silicon substrate 15 by spin coating or the like, and the thickness of the waveguides 17 to 22 is formed over the entire upper surface. Is formed. Then, this waveguide layer is processed by the ion etching method or the like along the pattern of the waveguides 17 to 22 to form the waveguides 17 to 22, and to expose the lower cladding layer around the waveguides. Then, an upper clad layer is formed on the lower clad layer and the waveguides 17 to 22 by a spin coating method or the like, and a clad layer 16 in which the lower clad layer and the upper clad layer are integrated is completed. Obtain a waveguide grating type optical multiplexer / demultiplexer.

Here, the following expressions hold for the effective refractive index of the TE polarization and the effective refractive index of the TM polarization in the arrayed waveguide grating type optical multiplexer / demultiplexer.

[0019]

(Equation 1)

(Equation 2)

The parameters in these equations are as follows: ns: the effective refractive index of the slab waveguide (the effective refractive index differs between the TE-polarized light and the TM-polarized light) d: of the adjacent waveguide constituting the arrayed waveguide at the input end of the output-side slab waveguide Distance between centers ΔL: difference in length of adjacent waveguides forming array waveguide m: diffraction order λ: wavelength Lf: focal length of slab waveguide on output side θ: light ray in slab waveguide on output side X: the light condensing position (output position) at the output end of the output-side slab waveguide nc: the effective refractive index of the arrayed waveguide (the effective refractive index differs between TE-polarized light and TM-polarized light). )

D, Lf, θ and x are specifically shown in FIG. As shown in this figure, Lf is the output end (slab waveguide 2) of the outermost waveguide 17s among the waveguides 17, 17,.
0s) to the center of the input end (output end of the slab waveguide 20) 24c of the output waveguide 22c located at the center of the plurality of output waveguides 22, 22,. Is the distance. is the center of the output end 23c of the waveguide 17c positioned at the center of the waveguides 17 constituting the arrayed waveguide 18, and the center of the plurality of output waveguides 22, 22. Input end (output end of slab waveguide 20) 24c of output waveguide 22c located at
And the line connecting the center of the output end 23c and the center of the input end 24s of any output waveguide 22s. x is a position on the x-axis orthogonal to the central axis y of the slab waveguide in the light guiding direction and passing through the center of the input end 24c of the output waveguide 22c located at the center.

A design example of each parameter of the arrayed waveguide grating type optical multiplexer / demultiplexer of this embodiment will be described below. These values are not particularly limited, and can be appropriately set according to desired characteristics. Note that n
s (TE), ns (TM) and nc (TE), nc
(TM) sets a common value for all of a plurality of wavelengths propagating through the optical multiplexer / demultiplexer. ns (TE): 1.533706 (all wavelengths) ns (TM): 1.525438 (all wavelengths) d: 11 μm ΔL: 71.086 μm m: 70 λ: 1545.322 nm to 1557.363 nm (0.8 nm interval, The center wavelength λc is 1550.918n
m) Lf: 7500 μm nc (TE): 1.53197 (all wavelengths) nc (TM): 1.52364 (all wavelengths)

As described above, suppose that nc (TE) =
When nc (TM) = 1.53197 (all wavelengths), T
The light condensing position of the output end of the slab waveguide 20 of the light of each polarization E and TM coincides with each wavelength. FIG. 5 shows the relationship between the wavelength and the light condensing position (output position) in such a case. In this example, the wavelength interval is 0.8 nm. Therefore, the interval between the condensing positions (output positions) x of each wavelength is 25 μm.
Becomes This interval can be increased by increasing Lf, as can be seen from the above equation (2) Lf. In the design of the optical multiplexer / demultiplexer of the present invention, first, as shown in FIG.
E) Fix at the position where nc (TM). That is, the light condensing positions of the respective wavelengths of one polarization are arranged at equal intervals in the position shown in FIG. Then, between these converging positions, the converging positions of the light of each wavelength of the other polarization are set.
Then, the condensing positions of one polarization and the other polarization are alternately arranged. Therefore, multiplexed light having a plurality of different wavelengths input to the input waveguide 21 can be output from each output waveguide for each wavelength and each polarization.

FIG. 6 shows that nc (TE) is 1.
53197 (all wavelengths), nc (TM) 1.52364
6 is a graph showing the relationship between the wavelength and the light condensing position (output position) when (all wavelengths) is set. The graphs of the TE polarization and the TM polarization are parallel straight lines, and in the graph for each polarization, the light condensing positions of each wavelength are at intervals of 25 μm.
Then, in the polarizations having the same wavelength, the condensing position (output position) of the TM polarization is 265 μm away from the condensing position (output position) of the TE polarization. If an output waveguide for TE polarization and an output waveguide for TM polarization are arranged at these condensing positions, the TM polarization and the TE polarization can be separated and output for each wavelength.

265 μm is equivalent to 10 channels (25 μm) having a distance of 25 μm between light-condensing positions for each wavelength in each polarization.
× 10 = 250 μm) and half (25 μm / 2 = 1)
2.5 μm) (262.5 μm).
Therefore, the interval between the output waveguides for TE polarization and TM polarization is 12.5 μm. Therefore, by arranging the output waveguides for TE polarization and TM polarization alternately at an interval of 12.5 μm at the output end of the slab waveguide on the output side, desired characteristics can be obtained. In this example, the width of the output waveguide is about 7 μm. Therefore, the focusing position is 12.5μ
The output waveguides can be arranged in parallel so as to have m intervals. At this time, the interval between adjacent output waveguides is 5.5.
μm, which is sufficiently far away that no light leaks between the output waveguides.

For reference, the TM polarization of the array waveguide and T
FIG. 7 shows the calculation result of the light condensing position (output position) x for the light having the center wavelength when the effective refractive index of the E-polarized light is changed, that is, the arrangement position of the output waveguide. It can be seen that the condensing position (output position) x can be adjusted by selecting the effective refractive index of the array waveguide of both polarizations.
In this embodiment, the FSR (Free Spectrum Ra) is used.
nge) is 22.1 nm and the bandwidth of λ (1557.
363-1545.322 = approximately 12 nm), so that no problem is caused by light having different diffraction orders.

A simulation was performed using the beam propagation method. As shown in FIG. 1 and FIG. 4, when channel 1 (ch. 1), channel 2 (ch. 2),. FIG. 8 shows the transmission characteristics of No. 8. It is clear that only the TE polarized light having the center wavelength of 1551 nm is selectively output. On the other hand, ch. FIG. 9 shows the transmission characteristics of No. 24. Wavelength 155
It is clear that only the TM polarization having a center wavelength of 1 nm is selectively output. Therefore, the wavelength of 1551 nm
Can be separated and output separately.

Further, using the above parameter design example,
As shown in FIG. 10, an arrayed waveguide-grating type optical multiplexer / demultiplexer for outputting light of eight wavelengths λ1, λ2, λ3,..., Λ8 for each of the TE polarization and the TM polarization was manufactured. . The cladding layer and each waveguide were manufactured using fluorinated polyimide.

FIG. 11 shows that in the arrayed waveguide grating type optical multiplexer / demultiplexer, multiplexed light of λ1 to λ8 is input to an input waveguide, and ch. 1 to ch. 1
6 is a graph showing the relationship between wavelength and transmittance actually output from FIG. Each ch. It can be seen from FIG. 7 that light separated for each wavelength and for each polarization is output. 12 and 13
Are ch. 5 and ch. 13 is a graph showing wavelength-transmittance characteristics of light output from FIG. Wavelength 155
Light having a center wavelength of 0 nm is separated into TE polarized light and TM polarized light. 5 and ch. It is clear that each of them is output from the control unit 13. Therefore, in an arrayed waveguide grating type optical multiplexer / demultiplexer actually manufactured using fluorinated polyimide, characteristics that separate multiplexed light of a plurality of wavelengths for each wavelength and for each polarization can be obtained. Can be confirmed.

As described above, in the arrayed waveguide grating type optical multiplexer / demultiplexer of the present invention, by forming an arrayed waveguide having a large difference between the effective refractive indices of both polarized waves, it is possible to change the wavelength and the polarization of each polarized light. Light can be output every time. Although the effective refractive index of each polarization varies depending on the wavelength band to be transmitted, it cannot be particularly limited,
In the wavelength band used by the optical multiplexer / demultiplexer, the TM of the array waveguide
The difference between the effective refractive index of the polarized light and the effective refractive index of the TE polarized light of the array waveguide is 0.0004 or more, preferably 0.000
Desirably, it can be about 5 or more. as a result,
When ΔL, m, and d are set to the values shown in the above parameter design example, the interval between the output waveguides can be set to 12.5 μm or more, and the wavelength and the polarization can be simultaneously separated. A possible optical multiplexer / demultiplexer can be obtained.

As described above, the operation of demultiplexing light for each polarization and for each wavelength has been described here for the sake of convenience. However, the optical multiplexer / demultiplexer of the present invention has reversibility. Conversely, an operation of multiplexing light can be performed. That is, contrary to the arrow shown in FIG.
2, 22,... Are input waveguides, and when a plurality of lights having different polarizations and / or wavelengths are input to these waveguides, a plurality of lights having different polarizations and wavelengths are multiplexed. The multiplexed light, the input waveguide 21 as an output waveguide,
You can output from here.

[0032]

As described above, in the present invention,
An optical multiplexer / demultiplexer capable of simultaneously separating and synthesizing wavelength and polarization can be provided. Therefore, instead of the polarization beam splitter and the two optical multiplexers / demultiplexers, a single optical multiplexer / demultiplexer can constitute a polarization / wavelength multiplexing transmission circuit, which can save space and reduce loss.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of the configuration of an arrayed waveguide grating type optical multiplexer / demultiplexer according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA shown in FIG.

FIG. 3 shows 6FDA / copolymer in a copolymer as a material of a waveguide.
It is the graph which showed the relationship between the ratio of TFDB and the refractive index of a copolymer.

FIG. 4 is an enlarged view of a slab waveguide showing parameters d, Lf, θ, and x used when obtaining an effective refractive index.

FIG. 5: Assuming that nc (TE) = nc (TM) = 1.53
Wavelength and focusing position (output position) for 197 (all wavelengths)
It shows the relationship with.

FIG. 6 shows nc (TE) of 1.53197 (all wavelengths),
It is the graph which showed the relationship between the wavelength and light-collecting position (output position) when nc (TM) was set to 1.52364 (all wavelengths).

FIG. 7 is a graph showing a calculation result of an arrangement position of an output waveguide when an effective refractive index of TM polarization and TE polarization of an arrayed waveguide is changed.

FIG. 8 shows ch. 8 is a graph showing transmission characteristics of No. 8;

FIG. 9 shows ch. 24 is a graph showing the transmission characteristics of No. 24.

FIG. 10 is a schematic configuration diagram of an optical multiplexer / demultiplexer actually manufactured using fluorinated polyimide.

11 is a diagram illustrating an arrayed waveguide grating type optical multiplexer / demultiplexer shown in FIG. 10 in which multiplexed light of λ1 to λ8 is input to an input waveguide, and ch. 1 to ch. 1
6 is a graph showing the relationship between wavelength and transmittance actually output from FIG.

FIG. 12 shows an example of the arrayed waveguide grating type optical multiplexer / demultiplexer shown in FIG. 5 is a graph showing wavelength-transmittance characteristics of light output from FIG.

FIG. 13 shows an example of the arrayed waveguide grating type optical multiplexer / demultiplexer shown in FIG. 13 is a graph showing wavelength-transmittance characteristics of light output from FIG.

FIG. 14 is a block diagram showing an example of a conventional polarization / wavelength multiplex transmission circuit.

FIG. 15 is a plan view showing an example of an arrayed waveguide grating type optical multiplexer / demultiplexer.

[Explanation of symbols]

17: waveguide, 18: array waveguide, 19: slab waveguide (first slab waveguide), 20: slab waveguide (second
, Slab waveguides), 21 ... input waveguides (input / output waveguides), 22 ... output waveguides (input / output waveguides).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Oura 1440, Mukurosaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Office (72) Inventor Kenichiro Asano 1440, Musaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Office ( 72) Inventor Hideyuki Hosoya 1440 Mutsuzaki, Sakura City, Chiba Prefecture Fujikura Co., Ltd. Sakura Office F-term (reference) 2H047 KA04 KA12 LA18 LA21 QA05 TA22

Claims (8)

[Claims] An array waveguide in which a plurality of waveguides having different lengths are arranged in parallel; first and second slab waveguides provided at both ends of the array waveguide; A waveguide including an input / output waveguide provided outside the slab waveguide and a plurality of input / output waveguides provided outside the second slab waveguide is provided in the cladding layer. An arrayed waveguide grating type optical multiplexer / demultiplexer, comprising: a multiplexed light beam of a plurality of lights having different wavelengths being input to an input / output waveguide provided outside the first slab waveguide; An optical multiplexer / demultiplexer, which outputs light separated for each wavelength and for each polarization from each of a plurality of input / output waveguides provided outside the second slab waveguide. 2. The optical multiplexer / demultiplexer according to claim 1, wherein at one end of the second slab waveguide on the side of the plurality of input / output waveguides, one polarization and the other polarization are provided. An optical multiplexer / demultiplexer, wherein the positions of condensing polarized waves are different. 3. The optical multiplexer / demultiplexer according to claim 1, wherein the birefringence of the arrayed waveguide is utilized. 4. The optical multiplexer / demultiplexer according to claim 1, wherein the cladding layer and the waveguide formed therein are made of plastic. . 5. The optical multiplexer / demultiplexer according to claim 4, wherein
An optical multiplexer / demultiplexer, wherein the plastic is a fluorinated polyimide. 6. The optical multiplexer / demultiplexer according to claim 1, wherein the cladding layer is provided on a substrate. 7. The optical multiplexer / demultiplexer according to claim 1, wherein, in a wavelength band used by the optical multiplexer / demultiplexer, an effective refractive index of one polarized light of the array waveguide and the effective refractive index of the polarized light. The difference from the effective refractive index of the other polarization of the array waveguide is 0.00
An optical multiplexer / demultiplexer, which is at least 04. 8. The optical multiplexer / demultiplexer according to claim 1, wherein light having one or both of a polarization and a wavelength different from each other is input to each of the plurality of input / output waveguides. Sometimes, these lights are multiplexed and output from an input / output waveguide provided on the first slab waveguide side.