JPH01126096A - Optical switch for wavelength multiplex signal - Google Patents

Abstract

PURPOSE:To realize the optimization of a function with a small scaled hardware of which regularity is high by separating the wavelength conversion function and the optional fetching function of a signal which are possessed by a light wavelength selector and optimizing the respective needed pieces of them. CONSTITUTION:The wavelength multiplex signal of (n) wave flows to input light highways 1-1-1-m. A light wavelength conversion device 2-1-2-m executes conversion not so as blocking does not occur to the light space switches 6-1-6-n of a next stage and not so as the wavelength of the light flowing to the identical output light highway is not mutually the same. The light of which wavelength is converted is passed through the light space switches 6-1-6-m after being separated by optical demultiplexers 3-1-3-m. Besides, it is collected again by optical multiplexers 9-1-9-m and outputted through light wavelength converter 10-1-10-m.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technology for converting signals between a plurality of highways, and particularly to an optical switch that handles wavelength multiplexed signals.

[Conventional technology]

As a signal switching circuit between a plurality of optical highways through which wavelength-multiplexed signals flow, Japanese Patent Application Laid-Open No. 61-288593
etc. are known as conventional examples. This conventional optical switch performs switching between m optical highways multiplexed with n waves, and after branching each input optical highway into m lines to form i lines, an optical wavelength selector is used. In this method, the output is obtained by re-combining every m lines through the cables. Here, the optical wavelength selector is a circuit that is the basis of this switch, and is a circuit that has both a wavelength conversion function and a selection function of light waves. The feature of this switch is that signals can be exchanged in a non-blocking manner.

(Problems to be Solved by the Invention) The first problem with the conventional example described above lies in the amount of required hardware.

That is, in the above-mentioned conventional technology, in order to perform switching between m n-wavelength multiplexed signals, a number of optical wavelength selector circuits are required. This wavelength selector circuit is a circuit that has a complex function of wavelength conversion between n-wave optical signals and selective extraction of a wave of an arbitrary value among the n-waves, and its hardware is large-scale and expensive. This becomes,
The circuit shown in the prior art embodiment is also shown to be a combination of nXn electrical switches, n O/E converters and n E10 converters.

The second problem with the conventional example is that it uses an optical branch circuit with an output of 1 m. Only one of the m branched outputs is actually switched, and the remaining m -1 optical outputs flow uncontrolled.

In other words, by using an optical branching circuit, the optical power is definitely attenuated to -, which is a big problem when m is conventionally made large.

The present invention has been made for the purpose of solving the problems of the prior art as described above.

[Means for solving problems]

The above object can be achieved by separating the wavelength conversion function and the selective signal extraction function that the optical wavelength selector has, and then optimizing the required number of each. In addition, in the actual conversion system, complete non-blocking (non-blocking) as aimed at in the conventional example is required.
Rearrangement non-blocking (reconfigurable non-blocking) property, which can be maintained by changing the connected line, is often sufficient. Focusing on this point, reducing the hardware scale of the − layer also plays a major role in solving the above problems.

[Effect]

In the optical switch of the present invention, within one optical highway, there is a wavelength conversion switch that performs mutual wavelength swapping between n wavelength multiplexed signals (λ1 to λ,), and a switch that performs spatial switching between signals of the same wavelength. Use both matrices. The reason why the above-mentioned conventional technology requires as many as - wavelength selector circuits is that both of these functions are combined into one (or one block) circuit. It becomes possible to reduce the amount of hardware. - For example, when configuring a non-block switch, 2m wavelength conversion devices (n wave input, 2n wave input,
-1 wave output) and 2n-1 m×m optical space switches. Moreover, if it is a rear angle non-blocking switch, only 1m wavelength converters and n mXm optical space switches are required.

The reason why an optical branch circuit was required in the prior art is the same, and by dividing the functions of each switch, there is no need to use an optical branch circuit.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an optical switch according to an embodiment of the present invention. Input optical highway 1-1~1n
Wavelength multiplexed signals of n waves of λ1 to λ are flowing through the channels. The 2-1 to 2m optical wavelength conversion device has the function of exchanging the wavelengths λ1 to λ of these n waves. This wavelength conversion device.

To prevent blockage from occurring in the next stage optical space switch.

The optical jumper converts the light flowing on the same output optical highway so that it does not have the same wavelength. After being passed through n m x m optical space switch matrices and subjected to switching, it is combined into rays 7-1 to 7-m. Finally, an optical wavelength converter 10-1 replaces the wavelength within each optical highway.
10-m and then connected to the output optical highway 11-1 to 11-m.

As described above, in this embodiment, an optical switch is constituted by a total of 2 m optical wavelength converters, a total of n m x m optical space switches, and m demultiplexers and multiplexers, respectively. This requires much less hardware than the conventional switch configuration, which required an amount of hardware proportional to (n Because of this, it is also suitable for integration.Another major feature is that the use of a demultiplexing/nine-multiplexing circuit eliminates the light attenuation (1/m2) that occurs when 5 branches and 2 converges occur. However, the optical switch of this embodiment has the disadvantage that it is not a completely non-blocking switch network, but a relocation type non-blocking switch network.

In actual switched networks, complete non-blocking is rarely required, and relocation type non-blocking is often sufficient for practical use.

FIG. 2 shows another embodiment of the present invention. The switch configuration of this embodiment is specifically similar to the embodiment of FIG.
The difference between the two is number 21! In the embodiment 1, the output of the optical wavelength converter is not n waves but 2n waves of λ1' to λ' 2n-1.
It is at the point where it is a -1 wave.

Along with this, the number of optical space switch matrices has also increased from n to 2n-1.

By doing this, it becomes possible to provide the switch network with complete non-blocking property. Even with this configuration, the required amount of hardware is sufficiently smaller than in the conventional case.

FIG. 3 shows an example of the configuration of an optical wavelength converter which is an important component of the optical switch of the present invention. In this configuration example, an optical amplitude modulator is applied to optical wavelength conversion. First, input light is separated into wavelengths by a demultiplexer 12, and then 13-1 to 13-13.
-n two-wave branching, 1 = 1, each of which is 1
The optical amplitude modulators 4-1 to 14-n and 15-1 to 15-n receive modulation by the outputs of variable frequency oscillators 16-1 to 16-n. The modulation frequency is changed to Δω optical signal by As1n(ω
t+φ), this modulation is expressed as follows.

As1n(Δ(1) t) sin(ωt + (+) Therefore, when the modulation inputs to the modulators 14-i and 15-i are made in phase, the output of the confluencer 17-1 is A5in(out
) sin(ωt+ O)+A cos(otlIt)c
os (ω is 10) + cos ((ω − Δω) t + θ) co
s((ω+Δω)t+θ)=eos((ω−Δω)=10), and a frequency lower by Δω is obtained. Similarly, when the phase is reversed, As1n (Δ(1) t) sin (ωt + 0) − A
cos(Δωt)cog(ωt−f?)=cos((ω
+Δω) becomes 10), and a frequency higher by Δω is obtained. By controlling this frequency shift amount, it becomes possible to perform wavelength switching between n wavelengths (11 to 1 m).

FIG. 4 shows another embodiment of the invention. The feature of this embodiment is that it is constructed by combining switches in the order of space switch - wavelength converter - space switch. n coming in from input optical highway 1-1 to 1-n
Wavelength multiplexed signals are first separated into wavelengths by optical demultiplexers 3-1 to 3-m, grouped into wavelengths, and switched by an mXk optical space switch matrix. Here, the number of lines on the output side must be selected to be equal to or larger than m. The outputs of each optical space switch are combined one by one, and then combined with an optical multiplexer. After switching the wavelengths with an optical wavelength conversion device, the outputs are sent to an optical demultiplexer and an optical space switch matrix as in the previous stage. and connected to output optical highways 11-1 to 11-m via optical multiplexers.

In this embodiment as well, if you select = m, you can ensure the rear array non-blocking property, and if you select = 2m-1, you can ensure the non-blocking property. requires an optical space switch matrix and 2n optical multiplexers and optical demultiplexers. What are the advantages and disadvantages of the embodiments shown in FIGS. 1 and 2?

The decision is made based on the performance and price of these hardware, and you can choose one depending on the situation.

[Effects of the Invention] According to the present invention, signal exchange between optical highways through which wavelength-multiplexed signals flow can be realized using small-scale, highly regular eight-domain hardware. Furthermore, since no branch circuit is included, signals can be used without being wasted, so the insertion loss of the switch circuit can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an optical switch according to a first embodiment of the present invention, FIG. 2 is a block diagram of an optical switch according to a second embodiment, and FIG.
The figure is a block diagram showing an example of the configuration of an optical wavelength converter, and FIG. 4 is a block diagram of an optical switch according to another embodiment of the present invention.

Claims (1)

[Claims] 1. In a device for exchanging signals between optical highways to which wavelength division multiplexed optical signals are supplied, an optical wavelength exchange device and a demultiplexer that switch wavelengths of signals within the highway. 1. An optical switch for wavelength multiplexed signals, comprising as constituent elements an optical space switch matrix, and a multiplexer. 2. In the wavelength multiplexed signal optical switch described in item 1,
The components include twice the number of optical wavelength converters as the number of input optical highways, the same number of demultiplexers and the same number of multiplexers, and the same number of optical space switch matrices as or more than the number of multiplexed wavelengths. An optical switch for wavelength multiplexed signals featuring: 3. In the optical switch for wavelength multiplexed signals described in paragraphs 1 and 2, one optical wavelength conversion device is connected to each of the input optical highway and the output highway, and the output of each optical wavelength conversion device on the input side is connected to each of the input optical highway and the output highway. Connect the input line of a demultiplexer that separates the wavelengths multiplexed into a line, and the multiplexer output line to the input line of each optical wavelength multiplexing converter on the output side, 1. An optical switch for wavelength multiplexed signals, which is characterized in that lines through which the waves flow are grouped together, each line is connected to an optical space switch matrix, and each of its output lines is connected to an input line of a different demultiplexer. 4. In the optical switch described in item 1, the number of multiplexed wavelengths is 2.
Constructs twice the number of optical space switch matrices, twice the number of demultiplexers as the number of input optical highways, multiplexers equal to or greater than the number of optical highways, and the same number of wavelength conversion devices. 1. An optical switch for wavelength multiplexed signals, characterized by comprising: 5. In the optical switch described in paragraphs 1 and 4, the lines carrying signals of the same wavelength among the outputs of each demultiplexer are collected and passed through the optical space switch matrix, and the outputs of each optical space switch matrix are connected one by one. Wavelength multiplexing characterized in that optical space switch blocks, each of which is combined into a single line by a multiplexer, are connected to an input optical highway and an output highway, and one optical wavelength conversion device is connected between each of them. Optical switch for signals. 6. The optical wavelength conversion device in the optical switch described in items 1 to 5 includes one demultiplexer and one multiplexer, and twice as many optical 3 dB hybrids and optical amplitude modulators as the number of multiplexed wavelengths. What is claimed is: 1. An optical switch for wavelength multiplexed signals, comprising the component as a component.