JPH11352356A - Optical wavelength router - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the constitution even in plural transmission lines by introducing each of the light rays of N kinds of wavelengths inputted to the respective input ports of one optical multiplexer/demultiplexer to the respective desired output ports of the other optical multiplexer/demultiplexer. SOLUTION: The optical waveguide wavelength router 10 has a pair of the optical multiplexer/demultiplexers 12 (12a, 12b), an optical matrix circuit 13 consisting of many (n×n×N pieces) of conductive paths 13x to 13z for optical coupling of both optical multiplexer/demultiplexers 12 and optical gate devices 14 disposed at the respective conductive paths 13x to 13z of the optical matrix circuit 13. The optical multiplexer/demultiplexers 12 are capable of making the sepn. of the wavelength number of nN pieces indicated by the product of the wavelength number N of the multiplex light inputted to the input ports and the port number (n). The light rays λ1, λ2 of the respective wavelengths from the respective input ports (a)to (c) may, therefore, be respectively led out to n×n×N pieces of the output pots A1 to C2 , A3 to C4 , A5 to C6 in the state of respectively separating these light rays without overlapping the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength router for switching a wavelength division multiplexed signal light to a desired route for each wavelength.

[0002]

2. Description of the Related Art In an optical communication using a wavelength multiplexed signal, an optical wavelength router for switching a multiplexed light to a desired route for each wavelength is used. This type of conventional router includes a pair of multiplexers / demultiplexers for each transmission line composed of each optical fiber. Each multiplexer / demultiplexer on the input side functions as a duplexer having one input port. A plurality of output ports of these duplexers provided for each transmission path are connected to a plurality of output ports of the multiplexer / demultiplexer on the output side via an optical matrix circuit. The output-side multiplexer / demultiplexer functions as a multiplexer, and each one input port functioning as an output port is connected to a corresponding transmission line. In other words, a pair of multiplexers / demultiplexers provided for each transmission path are symmetrically connected to each other with a matrix circuit between the two multiplexers.

According to the above-mentioned conventional optical wavelength router, an optical gate element provided in each optical conducting path of an optical matrix circuit is connected and disconnected to each input port of one optical multiplexer / demultiplexer. The multiplexed light of each transmission line can be switched to each transmission line connected to each input port of the other optical multiplexer / demultiplexer, which is the other optical multiplexer / demultiplexer, for each wavelength.

[0004]

However, in the conventional optical wavelength router, as described above, since a multiplexer / demultiplexer having a single input port is used as a pair, a plurality of multiplexers / demultiplexers are used. In order to cope with the number of transmission lines, a number of multiplexers / demultiplexers corresponding to the number of transmission lines is required, and furthermore, a large number of optical couplers for separating and coupling multiplexed lights having different wavelengths for each transmission line are required. Therefore, in a multi-transmission line, the configuration of the optical wavelength router is complicated. Therefore, there has been a demand for an optical wavelength router that can simplify the configuration of a plurality of transmission paths without complicating the configuration.

[0005]

The present invention adopts the following constitution in order to solve the above points. <Structure> The present invention is an optical wavelength router for switching connection paths of multiplexed light obtained by superposing N kinds of wavelengths for each wavelength, each having n input ports and n × nx. The multiplexed light having N output ports and comprising the N types of light of each wavelength input to each of the input ports is output to the different output ports according to each of the input ports and each wavelength. A pair of optical multiplexer / demultiplexers,
An optical matrix circuit for connecting the output ports of the two optical multiplexer / demultiplexers, and each of the input ports of one of the optical multiplexer / demultiplexers provided on each conductive path of the optical matrix circuit; And an optical gate device for guiding each of the N wavelengths of light input to the optical multiplexer / demultiplexer to the desired output port of the other optical multiplexer / demultiplexer.

<Operation> In the optical wavelength router according to the present invention, a pair of multiplexers / demultiplexers each having n input ports and n × n × N output ports is used. ing. The output ports of these two multiplexers / demultiplexers are connected to each other via an optical matrix circuit in which an optical gate device is provided in each conduction path. By operating the optical gate device provided in the optical matrix circuit, each of the N wavelengths of light input to each of the input ports of one of the optical multiplexer / demultiplexers is converted into a desired light of the other optical multiplexer / demultiplexer. Each of the output ports can be guided.

Therefore, according to the present invention, as described above, each of the pair of multiplexers / demultiplexers is provided with n input ports. As described above, a single set of the multiplexer / demultiplexer is used without using n pairs of multiplexer / demultiplexers and without using n × N optical couplers as in the related art. Switching according to the wavelength of the multiplexed light can be performed.

Each of the pair of multiplexers / demultiplexers can be realized by combining a large number of diffraction gratings on one optical substrate. However, it is desirable to configure the multiplexer / demultiplexer with a conventionally well-known array waveguide diffraction grating from the viewpoint of simplifying the configuration. Also, as a gate device,
A conventionally well-known optical gate element can be used. Instead of the optical gate element, for example, an N × N switching element for switching an optical path can be used in combination with a wavelength conversion element.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a block diagram schematically showing an optical wavelength router according to the present invention. Optical wavelength router 1 according to the present invention
0 is n lights, specifically, for example, n light beams, each of which guides a multiplexed light having two wavelength components composed of components of different wavelengths λ1 and λ2, for example,
For example, multiplexed light is inserted into three optical fiber paths 11 (11a, 11b and 11c) to enable selection of a path for each wavelength.

The optical wavelength router 10 includes a pair of optical multiplexer / demultiplexers 1.
2 (12a and 12b) and a large number (n × n × N) of conducting paths (1) for optically coupling the two optical multiplexer / demultiplexers 12.
3x, 13y, 13z) Optical matrix circuit 13
And each conduction path (13x, 13x) of the optical matrix circuit 13.
y, 13z). Each optical multiplexer / demultiplexer 12 has three input ports (a, b, and
c), 18 output ports (A1 to A6, B1 to B6,
C1 to C6).

Each optical multiplexer / demultiplexer 12 can be constituted by a well-known array waveguide diffraction grating. FIG.
FIG. 3 is a plan view schematically showing an optical multiplexer / demultiplexer 12 including an arrayed waveguide diffraction grating. Array waveguide diffraction grating (AWG)
2, an optical substrate 15 such as quartz or a compound semiconductor, and a pair of input / output waveguide groups 16a and 16b formed on the optical substrate, as shown in FIG.
And a pair of slab waveguides 17a and 17b, and an arrayed waveguide group 18 between both slab waveguides 17a and 17b.

According to the array waveguide diffraction grating 12,
As is well known in the art, each input port (a, b,
The multiplexed light having the wavelengths λ1 and λ2 guided to c) is guided to one slab waveguide 17a via each waveguide (16a) constituting one input / output waveguide group 16a. From each waveguide (16a) to the slab waveguide 17a
The multiplexed light guided to the waveguides is diffracted to excite the respective waveguides of the arrayed waveguide group 18 with different phases for respective input ports (a, b, c).

Therefore, each multiplexed light (.lambda.1 and .lambda.2) having a phase difference as each input port information is branched into each waveguide (16).

Each of the waveguides (1
The multiplexed light guided to 8) is guided to the other slab waveguide 17b via each waveguide. Each multiplexed light guided to the other slab waveguide 17b is diffracted by the slab waveguide 17b for each waveguide (18). In order to guide multiplexed light to the slab waveguide 17b, both slab waveguides 17a are used.
Since the lengths of the respective waveguides (18) of the arrayed waveguide group 18 provided between the waveguides 17 and 17b are different from each other by a predetermined value (ΔL), the multiplexing from the respective waveguides guided to the slab waveguide 17b is performed. Different phase difference conditions are added to the diffraction of light (λ1 and λ2) depending on the wavelength difference. Therefore, since the wavelength (λ1 and λ2) depends on the diffraction in the other slab waveguide 17b, the output ports A1 to C2, A3 to C4, and A5 are output from the slab waveguide 17b.
Light guided to C6 is demultiplexed into respective wavelength components. The above-described demultiplexing function of the optical multiplexer / demultiplexer 12 is shown by being arranged in the wavelength routing characteristics of FIG.

FIG. 3 is an explanatory diagram showing the wavelength routing characteristics between the input port and the output port of the optical multiplexer / demultiplexer 12 (12a, 12b) comprising the arrayed waveguide diffraction grating. As is clear from this figure, of the multiplexed light of wavelengths λ1 and λ2 input to the input port a, the light of wavelength λ1 is output to the output ports A1, A3 and A5, and the light of wavelength λ2 is output to the output ports A2 and A4. , A6. The wavelengths λ1 and λ2 input to the input port b are
Of the multiplexed light of wavelengths λ1 are output ports B1, B
3, the light of wavelength λ2 is output to the output port B2,
Output to B4 and B6. Further, of the multiplexed light of wavelengths λ1 and λ2 input to the input port c, the light of wavelength λ1 is output to output ports C1, C3 and C5, and the light of wavelength λ2 is output to output ports C2, C4 and C6. .

As described above, the optical multiplexer / demultiplexer 12 can separate nN wavelengths represented by the product of the number of wavelengths N of the multiplexed light input to the input port and the number of ports n. The optical multiplexer / demultiplexer 12 has a number of free spectral ranges equal to the number n of ports, that is, an optical multiplexer / demultiplexer 12 having three ports (a, b, c).
Has three free spectral ranges and its output shows three repetition periods. Thereby, light (λ1 and λ) of each wavelength from each input port (a, b, c)
2) in a state where each is separated without overlapping, and n
× n × N output ports A1 to C2, A3 to C4, A5
To C6.

Instead of the array waveguide diffraction grating 12, an optical multiplexer / demultiplexer having the same function as described above and realized by combining a large number of diffraction gratings on an optical substrate can be used. However, it is most desirable to configure the multiplexer / demultiplexer with a well-known array waveguide diffraction grating in terms of simplification of the configuration.

The optical multiplexer / demultiplexer 12 exhibits optically reversible characteristics. These pairs of optical multiplexer / demultiplexers 12a and 12a
b, both output ports A1 to C2, A3 to C4, A5 to C6
Referring again to FIG. 1, the optical matrix circuit 13
Connected to each other.

One optical multiplexer / demultiplexer 12a located on the input side
Functions as a demultiplexer, and the other optical multiplexer / demultiplexer 12b located on the output side functions as a multiplexer. Therefore, the duplexer 1
2b, the relationship between the input port and the output port is substantially inverted, but for the sake of convenience, the substantial input port of the duplexer 12b is hereinafter referred to as output port A1-C2,
A3 to C4, A5 to C6, and substantial output ports are referred to as input ports a, b, and c.

The optical matrix circuit 13 disposed between the splitter 12a and the multiplexer 12b is connected by a group of conductive paths (13x, 13y, 13z) showing three different wiring patterns.

A first group of conducting paths (13x) showing a parallel connection pattern connects the output ports A1 and C2 of the multiplexer 12a to the output ports A1 and C2 of the duplexer 12b, respectively. Second waveguide group (13y) showing a cross connection pattern
Connects the output ports A3 and A4, B3 and B4, C3 and C4 of the duplexer 12a to the output ports C3 and C4, A3 and A4, B3 and B4 of the multiplexer 12b, respectively. In addition, the third showing the cross connection pattern
Is the output port A of the duplexer 12a.
5 and A6, B5 and B6, C5 and C6 are connected to the output ports B5 and B6, C5 and C of the multiplexer 12b.
6, A5 and A6 respectively.

Each conduction path (13x, 13y, 13z) is provided with a gate device 14, such as a semiconductor optical amplifier (SOA), for interrupting light conduction. Although another gate element can be used as the optical gate device 14, the use of a semiconductor optical amplifier is advantageous in that a high extinction ratio can be obtained and optical amplification can be performed.

As shown in FIG. 3, the output ports A1 to C2, A3 to C4, and A5 to C6 of one multiplexer / demultiplexer 12a are input ports a and b of the duplexer 12a. ,
The light component of each wavelength for each c is guided. Therefore, each output port A1-C2, A3-C4, A
By opening and closing the optical gate device 14 provided in each of the conductive paths (13x, 13y, 13z) of the optical matrix circuit 13 connected to 5 to C6, the input ports a, b, and c of the desired duplexer 12a are opened. Light having a desired wavelength (λ1, λ2) can be guided to desired ports a, b, and c of the optical multiplexer 12b.

FIG. 4 shows ports a, b, and c of the demultiplexer 12a by switching each optical gate device 14, and the multiplexer 12b.
Of the wavelengths λ1, λ
It is explanatory drawing which arranged about 2 lights. The explanatory diagram shown on the left side of FIG. 4 shows, for light of wavelength λ1, for example, a conduction path 13x extending from the output port number A1 of the duplexer 12a.
By opening the optical gate device 14 provided in the optical multiplexer 12a, the light having the wavelength λ1 guided to the port a of the duplexer 12a can be guided to the port a of the multiplexer 12b.

FIG. 4 shows the light gate device 14 provided on the conduction path 13y extending from the output port number C4 of the splitter 12a for the light of the wavelength λ2. By operating, the light of the wavelength λ2 guided to the port c of the duplexer 12a can be guided to the port b of the multiplexer 12b.

Therefore, as shown in the explanatory view of FIG. 4, by selectively opening and closing the optical gate device 14, the optical multiplexer / demultiplexer 12 is not provided for each of the optical fiber paths 11a, 11b and 11c. Further, light of different wavelengths can be switched to a desired path, that is, a transmission path, with a very simple configuration without using a large number of optical couplers.

The conduction paths (13x,
13y, 13z) is preferably composed of a tape fiber or a multi-core fiber from the viewpoint of simplifying wiring management. When a tape fiber is used, n N-core fibers can be used.

FIG. 5 shows a modification of the optical gate device 14. Each set of output ports A1 and A2 of the duplexer 12a,
B1 and B2, C1 and C2, A3 and A4, B
3 and B4, C3 and C4, A5 and A6, B5
And conduction paths (13x, 13y, 13z) where wavelengths λ1 and λ2 make a pair, such as B6, C5 and C6.
Using a wavelength conversion element 14a having a function of mutually converting wavelengths and a switching function, that is, a gate function, and an N × N optical matrix switching element 14b provided for each pair of conductive paths. Can be.

Light having a wavelength λ1 input to one of the conversion elements 14a is output as light having a wavelength λ1 from the conversion element 14a, and light having a wavelength λ2 input to the other conversion element 14a is output from the conversion element 14a. When output as light of wavelength λ2, the wavelength of the output light is arranged in the order of λ1 and λ2 by the switching element 14b as shown in FIG. The wavelength λ1 input to one of the conversion elements 14a is obtained by the wavelength switching action of the two conversion elements 14a.
Is output from the conversion element 14a as light having a wavelength λ2, and the wavelength λ2 input to the other conversion element 14a.
Is output from the conversion element 14a as light having the wavelength λ1, the switching element 14b causes the wavelength of the output light to be in the alignment order of λ1 and λ2, as described above.

Therefore, by using the wavelength switching mechanisms 14a and 14b as shown in FIG. 5, when it becomes necessary to switch the wavelengths λ1 and λ2,
Even if the wavelength switching operation is performed by the operation a, the wavelength of the light input to the multiplexer 12b does not change depending on the presence or absence of the switching operation, and the setting of the optical multiplexer 12b according to the wavelength switching operation is performed. No changes are required.

[0031]

According to the present invention, as described above, each of the pair of multiplexers / demultiplexers is provided with n input ports, and each of the input ports is connected to each of the n transmission lines. By using an optical gate device provided in an optical matrix circuit between the two multiplexers / demultiplexers, it is possible to use a large number of optical couplers without using a plurality of sets of multiplexers / demultiplexers as in the related art. Instead, it is possible to perform switching according to each wavelength of multiplexed light, as in the conventional case, by using a single set of the multiplexer / demultiplexer, thereby simplifying the configuration of the optical wavelength router.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of an optical wavelength router according to the present invention.

FIG. 2 is a plan view schematically showing an example of the multiplexer / demultiplexer shown in FIG.

FIG. 3 is an explanatory diagram of wavelength routing characteristics showing a relationship between input and output of the multiplexer / demultiplexer shown in FIG. 2;

FIG. 4 is an explanatory diagram of a switching operation of the optical gate device shown in FIG.

FIG. 5 is a block diagram showing another example of the optical gate device according to the present invention.

[Explanation of symbols]

Reference Signs List 10 optical wavelength router 11 (11a, 11b and 11c) optical fiber path 12 (12a and 12b) optical multiplexer / demultiplexer (arrayed waveguide diffraction grating) 12a duplexer 12b multiplexer 13 optical matrix circuit 14 (14a, 14b) Optical gate device

Claims (4)

[Claims] 1. An optical wavelength router for switching connection paths of multiplexed light obtained by superimposing light of N kinds of wavelengths for each wavelength, each having n input ports and n × n × N ports. A plurality of output ports, each of which outputs the multiplexed light composed of the light of the N types of wavelengths input to each of the input ports to the output ports different from each other according to the input ports and the wavelengths. An optical multiplexer / demultiplexer, an optical matrix circuit connecting between the output ports of the two optical multiplexer / demultiplexers, and provided on each conduction path of the optical matrix circuit, and one of the optical multiplexer / demultiplexers is provided by the intermittent conduction path. An optical gate device for guiding each of the N wavelengths of light input to each of the input ports of the optical multiplexer to the desired one of the output ports of the other optical multiplexer / demultiplexer. 2. The optical wavelength router according to claim 1, wherein each of said optical multiplexer / demultiplexers comprises an arrayed waveguide diffraction grating. 3. The optical wavelength router according to claim 1, wherein said optical gate device is an optical gate element. 4. The optical wavelength router according to claim 1, wherein the gate device includes an optical path switching device.