JPH0968730A - Frequency multiplexing optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency multiplexing optical switch of simple constitution which decreases the number of wirings between blocks constituting this frequency multiplexing optical switch and has no three-dimensionally intersected wirings. SOLUTION: Optical matrix switches 43 to 45 are switches of input/outputs 3x3 and output the input signals of the single frequency of incoming ports 31 to 33 to arbitrary outgoing ports 34 to 36. An optical frequency router 11 of an input stage is a multiplex separating element which is inputted with the multiplexed signals of frequencies f2, f5, f8 from an input path 13 and outputs the light signals of the single frequencies f2, f5, f8 respectively to adjacently arranged ports b1 to b3, b4 to b6, b7 to b9. This router is connected to the incoming ports 31 to 33 of the optical matrix switches 43 to 45 corresponding to the respective frequencies f2, f5, f8 via an optical connecting path or links 41 of optical fibers. The outgoing ports 34 to 36 of the respective switches are connected via the links 41 to the incoming pots b1 to b3, b4 to b6, b7 to b9 of the frequencies f2, f5, f8 of the frequency router 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency multiplexing optical switch which is connected to a frequency multiplexing transmission line using light such as an optical fiber and which outputs an arbitrary frequency channel of an input route to an arbitrary output route. .

[0002]

2. Description of the Related Art Reference to a conventional device for a frequency multiplexing optical switch is "Introduction to Optical Switching Technology", edited by Ken-ichi Yukimatsu.
, Which describes three schemes. Part 1
One is a line that inputs the frequency-multiplexed optical signal of the input route to the frequency channel selection element, separates it by frequency, and inputs each of the separated frequency lights to the optical matrix switch and outputs it to the desired output route. It is an exchange method. The second is a method in which the optical signal of the incoming route is split into powers for the number of outgoing routes, input to the multi-frequency selection filter, and only the light of the desired frequency is output to the outgoing route. The third method is a method in which a line switching switch capable of setting a line for each frequency of an input multi-frequency optical signal is constituted by, for example, a 2x2 switch of an acousto-optic (AO) element.

[0003]

Among such conventional methods, the first method is advantageous in that the power loss is small and switching of a large number of routes can be easily realized. The conventional switch N (M, N is a natural number) that handles M multiple lines with frequency multiplicity N separates N frequency-dependent outputs by connecting frequency channel selection elements for each multiplex line. It is configured to connect to the matrix switch for each frequency. Therefore, even if only the input stage is considered, the NxM connection lines intersect three-dimensionally, the space factor is bad, and there is a drawback that it takes time to manufacture.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a frequency multiplexing optical switch having a simple structure.

[0005]

According to the present invention, input / output terminals are connected to M optical transmission lines for transmitting frequency-multiplexed optical signals frequency-multiplexed to a multiplicity N (M and N are natural numbers). In the frequency multiplexing optical switch for switching the frequency multiplexing optical signal between the input and output ends, the optical switch has M input terminals connected to the M optical transmission lines and receiving the frequency multiplexing optical signal. The frequency demultiplexed optical signals are demultiplexed, and M sets of N optical signals having different frequencies are output to the NxM output terminals, and M sets of N optical signals having different frequencies are input. A multiplexer element that has NxM input terminals and multiplexes N sets of N optical signals into a frequency-multiplexed optical signal of multiplicity N and outputs the multiplexed optical signals from the M output terminals. It has M input terminals to be input, and this input light N matrix switches that output the signals to the desired ports of the M output terminals and the M optical signals of the same frequency among the N optical signals obtained from the NxM output terminals of the demultiplexing element. First connecting means for connecting to the input terminals of the same switch of the matrix switches and M output terminals of the same switch of the N matrix switches are respectively the same as the input terminals of the multiplexing element. Second connecting means for connecting to M input terminals of the frequency.

Further, according to the present invention, M first ports for transmitting frequency-multiplexed optical signals each having a multiplicity of N and NxM for transmitting M sets of N optical signals having frequencies different from each other are transmitted.
When the frequency-multiplexed optical signal arrives at the M first ports, it is demultiplexed and output to the NxM second ports, and the NxM second ports are provided. An optical frequency router is provided which, when N optical signals having different frequencies arrive at the ports, multiplexes the signals and outputs the multiplexed signals to the M first ports.

In this way, M input / output terminals connected to the frequency multiplex transmission line and M output terminals of the demultiplexing element connected to each M input / output terminals of the N matrix switches. And M input terminals of the multiplexing element are adjacent to each other. Therefore, the connecting means of the optical fiber connecting the input and output ends of the switch or the optical connecting path on the optical wiring board are arranged in parallel, and the separation and multiplexing of the multiplicity N are performed inside the frequency router at the input and output stages. Therefore, the number of connection wirings is reduced as compared with the conventional method.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a frequency multiplexing optical switch according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a functional block diagram showing an embodiment of a frequency multiplexing optical switch according to the present invention. The frequency multiplexing optical switch 10 of the embodiment has two frequency routers 11 and 12, one of which, the ingress side frequency router 11, accommodates the frequency multiplexing optical transmission line of the optical fiber cable of the input path 13. , The other, that is, the output side frequency router 12 accommodates the frequency multiplexing optical transmission line of the optical fiber cable of the output route 14,
The circuit switching device outputs an arbitrary frequency channel of an incoming route 13 to an arbitrary outgoing route 14.

The frequency routers 11 and 12 may have the same configuration, and in the present embodiment, the maximum number of ports is 9, which is a 9x9 type optical routing element having a maximum frequency multiplexing number of 9. The logical configuration is, as shown in FIG. 3, provided with nine ports a of # 1 to # 9 and nine ports b of # 1 to # 9, and an optical signal of the frequency multiplexed input port a. To output port b. Each of the ports a1 to a9 and b1 to b9 has a frequency selection characteristic as shown in FIG. More specifically, when optical signals having frequencies f0 to f8 different from each other are input to the ports a1 to a9, the matrix 15
The optical signals having the frequencies shown in the columns of are output to the ports b1 to b9. Similarly, when the optical signals having the frequencies f0 to f8 are input to the ports b1 to b9, the optical signals having the frequencies shown in the rows of the matrix 15 are output to the ports a1 to a9. When applying such an optical routing element to the input side frequency router 11, only the input ports a1, a2 and a3 are used, and when applied to the output side frequency router 12, the output ports a1, a2 and a3 are used. Use only. In this example, the frequency used is f
2, f5 and f8.

FIG. 4 is a functional diagram showing the relationship between the ports used by the frequency routers 11 and 12 of FIG. 1 and their frequencies. In FIG. 3, when applied to the frequency router 11 on the ingress side, for example, ports a1, a2, and a3 adjacent to each other are used.
When optical signals of multiple frequencies f2, f5 and f8 are input to
As indicated by the solid blocks 16, 17 and 18 in the matrix 15, the optical signals of the frequency f2 are adjacent to each other at the port b1,
Similarly for b2 and b3, the frequency f5 is at ports b4, b5 and b6
Further, the frequency f8 is output to the ports b7, b8 and b9, respectively. That is, the same frequencies are collectively output to the adjacent ports. Conversely, when applied to the outgoing frequency router 12, the dotted block 1 in the matrix 15
Port b1 adjacent to each other as shown at 6, 19 and 20
~ B3, b4 ~ b6 and b7 ~ b9 are input with optical signals of frequencies f2, f5 and f8 respectively, the adjacent ports 1a
The optical signals of the multiple frequencies f2, f5, and f8 are output to 3a. In this way, the frequency of the frequency router 11 or 12
By appropriately selecting f0 to f8, multiple frequency separation and frequency multiplexing can be realized by using adjacent ports.

Assuming that the number of input / output ports a and b of the frequency router 11 or 12 shown in FIG. 3 is a natural number n (same for both input and output), NxM = n from the relation that the number of ports with frequency multiplicity N is M. Become. Since the number of input / output ports n is considered to be 144, a frequency router with M = 12 and N = 12 is realized. As the frequency interval, light having a wavelength M times that in the closest state, that is, light having a frequency f (M0 + Mi) is used. However, i = 1, 2, 3,
..., and M0 is a constant.

FIG. 2 conceptually shows an example of the mechanism of the optical frequency router 11 or 12 shown in FIG. In this embodiment, the optical frequency routers 11 and 12 are each formed in a planar shape on the optical wiring board 30. A planar waveguide is provided on the optical wiring board 30.
21 and 23 are formed, and both are connected to each other via a waveguide array 25. One of the planar waveguides 21 is a port
It has a1, a2 and a3 to which the waveguide array 22 is connected. The other planar waveguide 23 has ports b1 to b9 to which another waveguide array 24 is connected. The interconnected waveguide array 25 has a plurality of mutually different lengths,
N _W individual waveguides 25a are connected to the planar waveguides 2 and 23 at a pitch d and arranged in a plane.
The waveguide array 22 corresponds to the ports a1, a2 and a3,
It includes three individual waveguides arranged at an angle between adjacent ones, that is, a difference angle of Δθ.
It corresponds to. In the present embodiment, adjacent waveguides in the waveguide array 24 are also arranged at the differential angle Δθ. Assuming that the refractive indexes of the planar waveguides 21 and 23 are n _s , the difference in optical path length between adjacent waveguides 25a in the waveguide array 25 is ΔL, and the average of wavelengths used is λ ₀ , the wavelengths λ _i and λ The wavelength interval Δλ _{W from i + 1} is Δλ _W = 2n _s d Δθ / m, where m
= 2n _c ΔL / λ ₀ , and n _c is the equivalent refractive index in the waveguide array 25. The demultiplexed wavelength half-width Δλ _FW is Δλ
_FW = λ ₀ / (N _W m).

As described above, the wavelength spacing is M in the densest state.
Since it may be doubled, that is, MΔλ _W = Δλ _FW , the angle Δθ between adjacent waveguides of the waveguide array 22 is Δθ = λ ₀ / 2n
It can also be _s dMN _W.

Returning to FIG. 1, the outgoing port of the frequency router 11
An optical matrix switch 43 is arranged between b1 to b3 and the input ports b1 to b3 of the frequency router 12 as shown. Similarly, the optical matrix switch 44 is provided between the output ports b4 to b6 of the frequency router 11 and the input ports b4 to b6 of the frequency router 12, and the output port b7 to
Optical matrix switches 45 are arranged between b9 and the input ports b7 to b9 of the frequency router 12 as shown in the figure. Optical matrix switches 43, 44 and 45
In the present embodiment, is disposed on the optical wiring board 30, and an input signal of a single frequency is input to each of the input ports 31, 32 and 33 in response to a control signal from the outside, and
It is an input / output 3x3 switch that switches and outputs 34, 35 and 36. This enables the frequency multiplexing optical switch
Reference numeral 10 as a whole has the same function as that described as the first method in relation to the prior art, and does not provide a planar shape, that is, a complicated three-dimensional wiring or cross wiring on the optical wiring substrate 30, Can be realized.

The frequency router 11 at the input stage provided on the optical wiring board 30 has an input route connected to the ports a1, a2 and a3.
When multiplexed optical signals of frequencies f2, f5, and f8 are input from 13, the adjacent ports b1 to b3, b4 to b6, and b7 to b9
The optical signals of frequencies f2, f5 and f8 are respectively distributed to and output. The frequency router 11 is an optical matrix switch corresponding to each frequency f2, f5, and f8 via an optical connection path formed on the optical wiring board 30 or an optical fiber link 41.
Connected to input ports 31-33 on 43, 44 and 45. The egress ports 34-36 of each switch 43, 44 and 45 are linked 41
Frequency f2 of the frequency router 12 via link 42, similar to
It is connected to the input ports b1 to b3, b4 to b6 and b7 to b9 of f5 and f8. One of the links 41 is the adjacent frequency router 11 and three switches 43, 44 and 45 arranged adjacent to each other.
A route between ports 31-33 and the other link 42
Has a corresponding frequency router 12 and switches 43, 44 and
An optical signal path between adjacent three ports 34 to 36 at 45 is formed and arranged in parallel and orderly. Therefore, there is no crossover of the route wiring between the optical switches as in the conventional case.

Similarly, the frequency router 12 at the output stage provided on the optical wiring board 30 has input ports b1 to b3, b4 to b6 and
The optical signals of frequencies f2, f5, and f8 input from b7 to b9 are multiplexed and output to the output path 14 as a multiplexed signal.

In operation, for example a frequency router
When the optical signal of the channel f5 of the port a1 of 11 is connected to the port a3 of the frequency router 12, the transfer is performed by the following route in response to the control signal from the outside. That is, (port a1 of frequency router 11)-(ports b4 to b6)-(link
41)-(Ports 31 to 33 of optical matrix switch 20)-
(Ports 34 to 36)-(Link 42)-(Frequency router 12
B4 to b6)-(the same port a3). Thus, according to the present invention, complete circuit switching between a plurality of ports and between frequency channels can be realized without providing complicated three-dimensional wiring or cross wiring.

[0018]

As described above, according to the present invention, the frequency demultiplexing element for demultiplexing the frequency multiplexed channel at the input stage and the frequency demultiplexing optical element for performing the frequency multiplexing at the output stage have the same configuration of the frequency router. A plurality of terminals of the same frequency used and connected to the optical matrix switch from the input / output stage are arranged adjacent to each other. Therefore, the optical connection paths on the optical fiber or the optical wiring board are arranged in parallel in an orderly manner, and since the number of them is small, the three-dimensional wiring and the cross wiring in the prior art are eliminated, and the space factor is good,
It is possible to provide a frequency multiplexing optical switch with reduced manufacturing man-hours.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of a frequency multiplexing optical switch according to the present invention.

2 is a configuration diagram conceptually showing an example of a mechanism on an optical wiring board of the frequency router of the embodiment shown in FIG.

FIG. 3 is a diagram showing an example of a matrix of frequency characteristics of ports of the frequency router in the embodiment.

FIG. 4 is a functional diagram illustrating the relationship between ports and frequencies of the frequency router shown in FIG.

[Explanation of symbols]

 10 Frequency multiplexing optical switch 11, 12 Frequency router 13 Ingress route 14 Egress route 15 Matrix 43, 44, 45 Optical matrix switch

Claims (5)

[Claims] 1. An input / output terminal is connected to (M) optical transmission lines for transmitting frequency-division-multiplexed optical signals frequency-division multiplexed to a multiplicity N.
And N are natural numbers), and in the frequency multiplexing optical switch for switching the frequency multiplexing optical signal between the input and output ends, the optical switch is connected to the M optical transmission lines, and the frequency multiplexing optical signal is It has M input terminals to be input, and demultiplexes the frequency-multiplexed optical signal to demultiplex N optical signals having different frequencies from each other.
Group, NxM demultiplexing elements for outputting to the output ends, and N sets of NxM input terminals to which the N sets of optical signals having different frequencies are input, and N sets of the N sets of optical signals. Having a multiplexing element that multiplexes into a frequency-multiplexed optical signal of multiplicity N and outputs from M output terminals, and M input terminals to which optical signals of the same frequency are input,
N matrix switches for outputting the input optical signals to desired ports at M output terminals, and M of the optical signals obtained from NxM output terminals of the demultiplexing element, having the same frequency. First multiplexing means for connecting an optical signal to an input terminal of the same switch of the N matrix switches and M output terminals of the same switch of the N matrix switches are respectively multiplexed. And a second connecting means for connecting to M input terminals of the same frequency among the input terminals of the multiplexing element. 2. The frequency multiplexing optical switch according to claim 1, wherein the demultiplexing element and the multiplexing element include an optical frequency router that distributes an optical signal arriving at an input end to an output end according to a frequency. A frequency multiplexing optical switch characterized by. 3. The frequency multiplexing optical switch according to claim 2, wherein the frequency router is Nx of the demultiplexing element.
The M output terminals of the same frequency among the M output terminals are arranged adjacent to each other, and the M input terminals of the same frequency among the input terminals of the multiplexing device are arranged adjacent to each other. As described above, the frequency multiplexing optical switch characterized in that the used frequency is selected and the frequency characteristics are arranged. 4. M first ports for transmitting frequency-multiplexed optical signals each having a multiplicity of N, and N × M second ports for transmitting N sets of N optical signals having mutually different frequencies. When the frequency-multiplexed optical signal arrives at the M first ports, the Mx second optical signals are demultiplexed.
When the N optical signals of different frequencies arrive at the NxM second ports, the optical signals are multiplexed and output to the M first ports. Frequency router. 5. The optical frequency router according to claim 4, wherein the optical frequency router is provided with an optical wiring board, and the first optical frequency router is connected to the M first ports. And a second planar waveguide arranged on the optical wiring board and connected to NxM second ports, and arranged on the optical wiring board and having different optical path lengths. An optical frequency router comprising: a plurality of planar waveguides; and a planar waveguide array interconnecting first and second planar waveguides.