JPH0419622A - Constitution system for wavelength conversion switch - Google Patents

Abstract

PURPOSE:To increase the wavelength multiplicity of a wavelength conversion switches independently of the limit of variable wavelength width of each wavelength conversion element by providing a wavelength conversion part with plural wavelength conversion means for converting the wavelengths of respective selected optical signals by plural wavelength conversion element groups connected in multistages. CONSTITUTION:This wavelength conversion switch 7 is constituted of a wavelength leading part 2 consisting of plural selection filters for separating a wavelength multiplex input signal 1 wavelength-multiplied on an optical fiber transmission line, the wavelength conversion part 4 for converting the wavelengths of optical signals 3-1 to 3-n selected by respective selection filters and a wavelength multiplier 5 for multiplexing converted optical signals and forming a wavelength multiplexed output signal 6. The means 4 is provided with plural wavelength conversion means 8-1 to 8-n for converting the wavelengths of respective selected optical signals by plural wavelength conversion element groups connected in multistages. Thus, the wavelength multiplicity of the wavelength conversion switch 7 can be increased independently of the limit of the variable wavelength width.

Description

[Detailed Description of the Invention] [Summary] A wavelength conversion switch that switches between wavelengths of a plurality of information multiplexed on the wavelength axis in optical exchange that exchanges optical information from an optical fiber transmission line as light. Regarding the configuration method of the wavelength conversion switch, regardless of the limit of the variable wavelength width of the wavelength conversion element, the aim is to increase the wavelength multiplicity of the wavelength conversion switch. A wavelength selection unit (selection filter 1, selection filter 2,
..., a selection filter n, a wavelength conversion section that converts the wavelength of the optical signal selected by each selection filter, and a wavelength multiplexer that multiplexes the converted optical signals to generate a wavelength multiplexed output signal. The wavelength conversion section of the wavelength conversion switch is configured to include wavelength conversion means for converting the wavelength of each selected optical signal using a plurality of wavelength conversion element groups connected in multiple stages.

(Industrial Application Field) The present invention is a wavelength conversion switch that switches between wavelengths of a plurality of information multiplexed on the wavelength axis in optical exchange that exchanges optical information from an optical fiber transmission line as light. Concerning the method of construction.

[Background Art] In recent years, as the capacity of information has increased, the development of information transmission and exchange technology using light has become active.

Among these, wavelength-division optical switching, which transmits information by putting information on the wavelength of light and performs exchange by converting the wavelength, is less dependent on speed than time-division multiplexing, which uses multiplexing on the time axis. It has attracted attention due to its superiority in many aspects, and there is an urgent need to develop its technology.

Wavelength division type optical switching requires a wavelength conversion switch that converts the wavelength of input light to another wavelength and outputs it.

FIG. 8 is a block diagram of a conventional wavelength conversion switch.

The wavelength conversion switch includes an optical splitter 81 and m wavelength selection filters (82-1, 82-2, . . . , 82-m).
, m wavelength conversion elements (83-1, 83-2, . . .
83-m) and a coupler (or multiplexer) 84.

The optical signal branched by the splitter 81 passes through each wavelength selection filter (
82-1, 82-2, . . . , 82-m), and the optical signals with the wavelengths selected by each filter enter the respective wavelength selection filters (82-1, 82-2, . . . , 82-m). -m
) connected to the wavelength conversion element (83-1, 83-2, .
..., 83-m). Each wavelength conversion element (83
-1, 83 to 2, . . . , 83-m) convert the wavelength of the input optical signal and output it. Each wavelength conversion element (83
-1, 83-2, ..., 83-m) is output from the coupler 8
4, and output to an optical transmission line.

In wavelength division optical switching, a wavelength multiplexed signal with wavelengths λ1 to λ7 transmitted via an optical fiber transmission line is converted to a signal with another wavelength in the range of λ1 to λ1 by a wavelength conversion switch, and then optical Output to fiber transmission line.

First, the splitter 81 splits the input light (wavelength multiplexed signal of λ1 to λ□) 80 into m optical signals. The divided optical signals are each passed through m wavelength selection filters (82-1, 82-1, 82-1, 82-1,
2-2, . . . , 82-m). Each wavelength selection filter (82-1, 82-2,... 82-m
) select signals with wavelengths λ1, λ2, . . . , λ, respectively.

Next, each selected optical signal (λ1, λ2, ·, λff1
) are wavelength conversion elements (83-1, 83-2, .
..., 83-m). Each wavelength conversion element (83
-1, 83-2, ..., 83-m) are elements that convert the respective human signal lights (λ1, λ2, ..., c) into other wavelengths within the range of λ1 to λ. . For example, the wavelength conversion element 83-2 converts the input signal light of wavelength λ2 into λ, ~λ
Convert to another wavelength within the range of 1 and output. Which wavelength to convert to is determined by a call setting control unit outside the wavelength conversion switch. When the setting control unit controls the wavelength λ1 to be converted to λ2 and the wavelength λ2 to the wavelength, the wavelength conversion element 83
-1 converts the input signal λ1 to λ2, and the wavelength conversion element 83-2 converts the input signal λ2 to λ.

Wavelength conversion element (83-1, 83-2,...83-m)
The converted signal is again wavelength-multiplexed by a coupler 84 and output as output light 85 to an optical fiber transmission line.

As described above, for example, the exchange can be carried out by transferring the information carried on the wavelength λ1 to a signal having the wavelength λ2, and by transferring the information carried on the wavelength λ2 to the wavelength λ2.

(Problem to be Solved by the Invention) However, in the conventional system, a problem occurs when attempting to increase the wavelength multiplexing.

Generally, a wavelength conversion element using a semiconductor laser is used for a wavelength conversion switch. The input wavelength width and the output wavelength width of the wavelength conversion element are almost the same.

Therefore, the wavelength multiplexing degree of input light that can be input to the wavelength conversion switch is determined by the characteristics of the wavelength conversion element.

That is, when increasing the wavelength multiplexing, it is necessary to use a wavelength conversion element with a wide input wavelength width and output wavelength width, and a wide variable wavelength width. However, there is a limit to the variable wavelength width of the wavelength conversion element. For this reason, in the conventional system, there is a limit to the degree of wavelength multiplexing.

An object of the present invention is to increase the wavelength multiplicity of a wavelength conversion switch regardless of the limit of the variable wavelength width of a wavelength conversion element.

[Means to solve the problem]

FIG. 1 is a block diagram of the present invention. According to the present invention, wavelength selection filters (2-1, 2-2, . . . , 2-n
), and a wavelength selection filter (
a wavelength conversion unit 4 that converts the wavelength of each selected optical signal (3-1, 3-2, . . . , 3-n) selected by 2-1, 2-2, . . . , 2-n; A wavelength conversion switch 7 comprising a wavelength multiplexer 5 which wavelength-multiplexes the converted signals again and outputs a wavelength-multiplexed output signal 6 is assumed. The wavelength conversion means (8-1, 8-2, . . . , 8-n) includes the wavelength selection section 2
Each wavelength selection filter (2-1, 2-2, ..., 2-
Selected optical signals (3-1, 3-2, . . . , n) selected by
3-n) is converted by a group of wavelength conversion elements connected in multiple stages.

Each wavelength conversion means (8-1, 8-2, ..., 8n) is
An input selection optical signal of a certain fixed wavelength (3-1, 3-2, .
..., 3-n) to a signal of any wavelength, or an input selection optical signal of any wavelength (3-1, 3-2, . . . , 3)
-n) to a signal with a fixed wavelength, or an input selection optical signal (3-1, 3-2, ..., 3-n) with an arbitrary wavelength.
to a signal of any wavelength.

First, when converting an input signal with a fixed wavelength to a signal with an arbitrary wavelength (that is, when performing one-to-one wavelength conversion), each input selection optical signal (3-1, 3-2, . . .・・・
, 3-n) is arranged at the first stage. Then, this wavelength conversion element converts the wavelength within the range of its variable wavelength width. A wavelength conversion element having a variable wavelength width adjacent to that of the first stage wavelength conversion element is connected to the next stage. Generally, a wavelength conversion element on the short wavelength side adjacent to the variable wavelength width of the first stage wavelength conversion element and a wavelength conversion element adjacent on the long wavelength side are connected in parallel at a second stage position. Then, from the third stage onwards, the wavelength conversion element on the short wavelength side of the second stage is connected to a wavelength conversion element with an adjacent variable wavelength width on the short wavelength side, and the wavelength conversion element on the short wavelength side of the second stage is connected to The wavelength conversion element on the wavelength side is further connected to an adjacent wavelength conversion element on the long wavelength side having a variable wavelength width.

When it is desired to convert the input selection optical signal (3-1, 3-2, . . . , 3-n) to a wavelength on the short wavelength side, the first stage converts it to the wavelength on the shortest wavelength side of the wavelength conversion element. Thereafter, the signal is input to the wavelength conversion element on the short wavelength side of the second stage, and the wavelength is converted. From the second stage onwards, conversion by the wavelength conversion elements connected in multiple stages is sequentially repeated until the desired wavelength is reached.

On the other hand, if you want to convert to a wavelength on the long wavelength side, convert it to the longest wavelength of the wavelength conversion element in the first stage, and then input the signal to the wavelength conversion element on the long wavelength side in the second stage. , convert the wavelength. Then, from the second stage onwards, conversion is sequentially repeated until the desired wavelength is achieved.

A switch for extracting the output wavelength is provided on the output side of each wavelength conversion element connected in multiple stages, so that a signal converted to a desired wavelength can be extracted. As a result, a desired arbitrary wavelength is extracted as the output of the wavelength conversion element and output to the wavelength multiplexer 5.

Next, input selection optical signals (3-1, 3-2,
... 3-n) into a signal with a fixed wavelength (that is, when performing 1-to-1 and 1-to-n wavelength conversion). In this case, a wavelength conversion element having a variable wavelength width corresponding to an output signal light having a fixed wavelength is arranged at the final stage of a group of wavelength conversion elements connected in multiple stages. A wavelength conversion element having a variable wavelength width adjacent to the variable wavelength width of the wavelength conversion element in the final stage is connected to the preceding stage.

Generally, two wavelength conversion elements having variable wavelength widths on a short wavelength side and a long wavelength side adjacent to the variable wavelength width of the wavelength conversion element in the final stage are connected in parallel at a position before the final stage.

Further, wavelength conversion elements having adjacent variable wavelength widths are connected to each stage as wavelength conversion elements from the previous stage to the first stage. That is, of the two wavelength conversion elements in the previous stage of the final stage, a wavelength conversion element with an adjacent variable wavelength width on the short wavelength side is further connected to the stage before the wavelength conversion element on the short wavelength side, and the wavelength conversion element on the short wavelength side is connected in order. The wavelength conversion element on the wavelength side is connected to the previous stage.

A wavelength conversion element having an adjacent variable wavelength width on the long wavelength side is connected to the front stage of the wavelength conversion element on the long wavelength side, and wavelength conversion elements on the long wavelength side are sequentially connected to the front stage of the wavelength conversion element on the long wavelength side.

In addition, input selection optical signals of arbitrary wavelengths (3-1, 3-2,
..., 3-n), a switch is provided at the input section of each wavelength conversion element so that the input selection optical signal can be input to any wavelength conversion element. Furthermore, outputs of wavelength conversion elements corresponding to each fixed wavelength are connected to the wavelength multiplexer 5.

When the wavelength multiplexed input signal 1 is input to the wavelength conversion switch 7, first, the wavelength conversion means 8- for obtaining a desired output wavelength is applied.
The selection optical signal 3-i is selected by the wavelength selection filter 2-i connected to the wavelength selection filter 2-i.

Then, it is input via a switch to a wavelength conversion element having a variable wavelength width corresponding to the wavelength of the selected optical signal, and is sequentially converted by the wavelength conversion element until the final stage wavelength conversion element reaches the desired wavelength. The outputs of the wavelength conversion elements in the stages are output to the wavelength multiplexer 5 and wavelength multiplexed.

Finally, input selection optical signals (3-1, 3-2
1100, 3-n) to a signal of an arbitrary wavelength (when performing 1-to-1 and 1-to-n wavelength conversion in a wavelength-division communication path that accommodates multiple wavelength-multiplexed input/output highways) ), the wavelength conversion elements are connected in order from the wavelength conversion element with the variable wavelength width on the short wavelength side, and a switch is provided at the input and output parts of each wavelength conversion element to connect the input to any wavelength conversion element. Signal light (3-1, 3-2,...
., 3-n) can be input, and output signal light can be output from any wavelength conversion element. Furthermore, the output light of each wavelength conversion element can be input as input light to the wavelength conversion element on the short wavelength side in the preceding stage, so that it can be fed back from the element on the long wavelength side to the element on the short wavelength side.

The input signal of each input highway is filtered by a wavelength selective filter (2-
1, 2-2, ... 2-n), and input to the wavelength conversion element group connected to each wavelength selection filter (2-1, 2-2, ..., 2-n). be done. Then, the selected optical signal (3-1, 3-2,... 3
−n) is input to a wavelength conversion element corresponding to the wavelength. The wavelength conversion elements are connected in order from the short wavelength side, so if the desired wavelength is longer than the wavelength of the input signal,
Conversion is sequentially repeated in a group of wavelength conversion elements connected at a later stage until a desired wavelength is obtained. If the desired wavelength is shorter than the wavelength of the input signal, conversion is sequentially repeated in the wavelength conversion element group connected at the previous stage until the desired wavelength is reached. When the desired wavelength is reached, the output signal of the wavelength conversion element is taken out via the switch, wavelength multiplexed by the wavelength multiplexer 5, and sent out again to the optical transmission line.

0 Effect] The wavelength multiplexed signal transmitted through the optical fiber transmission line is input to the wavelength conversion switch 7 as the wavelength multiplexed input signal 1. In the wavelength conversion switch 7, the wavelength selection section 2 first decomposes the wavelength-multiplexed input signal 1 into individual wavelengths.

The wavelength selection section 2 includes wavelength selection filters (2-1, 2-2, .
... Consists of 2-n).

Each selected optical signal (3-1, 3-2, ... 3-) decomposed by a wavelength selection filter (2-1, 2-2, ... 2-n)
n) is input to the wavelength converter 4, and the wavelength converter 4 converts the wavelength of the selected optical signal (3-1, 3-2, . . . , 3-n) to a desired wavelength.

The wavelength converter 4 converts each selected optical signal (3-1, 3-2, . . .
・, 3-n) as input wavelength conversion means (81, 8-2)
,...8-n). Each wavelength conversion means (8-1
, 8-2, . . . 8-n) has a configuration in which a plurality of wavelength conversion elements are connected in multiple stages.

Details of the wavelength conversion means (8-1, 8-2, . . . 8n) will be described later. Wavelength conversion means (8-1, 8-2,...,
8-n), the converted signal is collected in the wavelength multiplexer 5, wavelength-multiplexed, and output from the wavelength conversion switch 7 as a wavelength-multiplexed output signal 6. .

The following three cases exist as the arrangement of the plurality of wavelength conversion elements of the wavelength conversion means (8-1, 8-2, . . . , 8-n). Firstly, in the case of one-to-one conversion that converts a signal of one wavelength to a signal of any one wavelength, secondly,
In the case of 1-to-1 or 1-to-n conversion, in which a signal of one wavelength is converted to signals of 1 or n wavelengths, the third step is to configure a wavelength-division communication path with a plurality of input/output highways. This is a case of 1-to-1 or 1-to-n conversion.

In the first case, the wavelength conversion means (8-1, 8-2, . . .
. , 8-n), fixed selection optical signals (3-1, 3-2, . . . , 3-n) having different wavelengths are input. Each wavelength conversion means (8-1, 8-2,..., 8-n
) A wavelength conversion element having a variable wavelength width corresponding to the wavelength of the selection optical signal (3) input to each wavelength conversion means (8) is arranged at the first stage of each wavelength conversion element group.

In the next stage, two wavelength conversion elements having variable wavelength widths on the short wavelength side and long wavelength side that are adjacent to the variable wavelength width of the first stage wavelength conversion element are connected in parallel, and from the third stage onwards, the second wavelength conversion element is connected in parallel. The wavelength conversion element on the short wavelength side of the second stage has a wavelength conversion element with an adjacent variable wavelength width on the short wavelength side, and the wavelength conversion element on the long wavelength side of the second stage has a wavelength conversion element with an adjacent variable wavelength width on the long wavelength side. wavelength conversion elements having adjacent variable wavelength widths are connected.

The input selection optical signals (3-1, 3-2, . . . 3-n) are respectively input to wavelength conversion means (8-1, 82, . . . 8-
n), and wavelength conversion is repeated sequentially to subsequent stages until the desired wavelength is obtained.

There is a switch at the output section of each stage of the wavelength conversion element to take out the output signal, and the signal converted to a desired wavelength is taken out via this switch and output to the wavelength multiplexer 5.

Next is the second case (1:1 and 1:n wavelength conversion). In this case, each wavelength conversion means (81, 8-2,...
. , 8-n), the selected optical signals (3-1, 3-2, . . . ..., 3-n) can be input. On the other hand, each wavelength conversion means (8-1, 8-
2..., 8-n) are fixed, and are configured to output signals of different wavelengths to the wavelength multiplexer 5. That is, each wavelength conversion means (8-1, 8-2
, . . . , 8-n), wavelength conversion elements corresponding to different wavelengths are arranged at the final stage of a group of wavelength conversion elements connected in multiple stages.

In the preceding stage, two wavelength conversion elements having variable wavelength widths adjacent to the variable wavelength width of the final stage wavelength conversion element on the long wavelength side and short wavelength side are connected in parallel. Further, as wavelength conversion elements from the previous stage to the first stage, wavelength conversion elements having adjacent variable wavelength widths are connected to each stage. That is, of the two wavelength conversion elements in the previous stage of the final stage, a wavelength conversion element with an adjacent variable wavelength width on the short wavelength side is further connected to the stage before the wavelength conversion element on the short wavelength side, and the wavelength conversion element on the short wavelength side is connected in order. The wavelength conversion element on the wavelength side is connected to the previous stage.

A wavelength conversion element having an adjacent variable wavelength width on the long wavelength side is connected to the front stage of the wavelength conversion element on the long wavelength side, and wavelength conversion elements on the long wavelength side are sequentially connected to the front stage of the wavelength conversion element on the long wavelength side.

In addition, input selection optical signals of arbitrary wavelengths (3-1, 3-2,
..., 3-n), a switch is provided at the input section of each wavelength conversion element (.

Input signal of arbitrary wavelength (3-1, 3-2,...3-n)
When input to the wavelength conversion unit 4, the wavelength conversion is performed using the wavelength conversion element of the wavelength conversion means 8-1 whose final stage is the wavelength conversion element corresponding to the desired output wavelength. The signal is first inputted to the wavelength conversion element corresponding to the wavelength of the input signal in the wavelength conversion means 8-i, and wavelength conversion is performed sequentially until reaching the final stage wavelength conversion element that obtains the desired wavelength. Then, the signal converted to the desired wavelength is output to the wavelength multiplexer 5.

In the third case (when performing 1-to-1 and 1-to-n wavelength conversion in a wavelength-division communication path that accommodates a plurality of wavelength-multiplexed human output highways), a wavelength-selective filter (2-1
, 2-2, . . . , 2-n) are converted into signals of arbitrary wavelengths selected by the respective wavelength conversion means (8-1, 8-2, . . . 8-
n).

Each wavelength conversion means (8-1, 8-2, ..., 8n) is
Each performs wavelength conversion of the optical signal of each input/output highway. Each wavelength conversion means (8-1, 8-2, .
..., 8-n), the wavelength conversion elements are connected in order from the wavelength conversion element with the variable wavelength width on the short wavelength side, and switches are provided at the input and output parts of each wavelength conversion element, so that arbitrary Input signal light (3-1, 3-2,...) to the wavelength conversion element
3-n) can be input, and output signal light can be output from any wavelength conversion element. Further, the output light of each waveform conversion element can be input as input light to the wavelength conversion element on the short wavelength side in the preceding stage, so that it can be fed back from the element on the long wavelength side to the element on the short wavelength side.

Wavelength selection filter (2-1, 2-2, ..., 2-n)
The signal of any wavelength selected in is input to the wavelength conversion element corresponding to the wavelength of the signal.

The wavelength conversion elements are connected in order from the shortest wavelength side, so if the desired wavelength is longer than the wavelength of the input signal, the wavelength conversion elements connected at the later stages will sequentially convert the wavelength until the desired wavelength is reached. Repeat the conversion.

If the desired wavelength is shorter than the wavelength of the input signal, conversion is sequentially repeated in the wavelength conversion element group connected at the previous stage until the desired wavelength is reached. When the desired wavelength is reached, the output signal of the wavelength conversion element is taken out via the switch and output to the wavelength multiplexer 5.

[Example] Hereinafter, an example will be described with reference to second unevenness FIG. 7.

FIG. 2 is a system configuration diagram of an embodiment of the present invention.

Optical signals with wavelengths λ1~ are wavelength multiplexed and transmitted over optical fiber transmission paths. The wavelength conversion switch 20 converts the wavelength of this wavelength-multiplexed optical signal and executes optical switching processing.

The input to the wavelength conversion switch 20 is a human-powered highway 21 that wavelength-multiplexes the optical signal to the wavelength λ1 ~, and the output is the output highway 22 that wavelength-multiplexes the optical signal to the wavelength λ1 ~ that has been wavelength-converted. be. The call setting control unit 23 controls which wavelength of the optical signal each of the optical signals having the wavelengths λ1 to is converted into. The input to the call setting control unit 23 is a call request signal 24, and the call setting control unit 23 generates control information such as which wavelength signal to convert to which wavelength based on this input, and performs wavelength conversion. The information is input to the switch 20 as control information.

The wavelength conversion switch 20 is a branching device 2 that branches the wavelength-multiplexed optical signal inputted from the input highway 21 into m pieces.
5, a wavelength selection filter group 26 that selects the wavelength of the optical signal branched into m pieces by the splitter 25, and a wavelength conversion element that converts the wavelength of the optical signal selected by the wavelength selection filter group 26 to another wavelength. A group 27 includes a coupler 28 that wavelength-multiplexes the converted signals of each wavelength and outputs the resultant signal to the output highway 22. The wavelength selection filter group 26 includes a plurality of wavelength selection filters (26-1, 26-2, . . . , 26
-m), the wavelength conversion element group 27 includes wavelength conversion elements (27-1, 27
-2,...27m).

A wavelength-multiplexed optical signal input from the input highway 21 is split into m signals by a splitter 25. Then, based on the information from the call setting control unit 23 regarding which wavelength signal is to be converted into which wavelength signal, wavelength selection filters (26-L, 262, . . . , 26-m) multiplex the signal. is decomposed and wavelength converted by wavelength conversion elements (27-1, 27-2, . . . 27-m) consisting of wavelength conversion elements connected in multiple stages.

Figure 3 shows the wavelength conversion elements (27-1, 27-2) in Figure 2.
, . . . , 27-m) is a relational diagram of input and output wavelength widths of wavelength conversion elements connected in multiple stages.

Now, the wavelength λ1,1~λ. , 7 to convert the wavelength of the input optical signal to another wavelength. In the conventional method, this λ3,1 to λ. , 7 variable wavelength widths were covered by one wavelength conversion element W, and wavelength conversion was performed. In the present invention, this λ1,1 to λ. +lll variable wavelength width is divided into n small wavelength widths, and n wavelength conversion elements each having a variable wavelength width are connected in multiple stages, resulting in a total wavelength of λ3. ．． ~λ. , 6 wavelengths, so that the wavelength can be converted arbitrarily.

That is, the variable wavelength width of λ1.1 to λI'+lI is converted by the wavelength conversion element W1, and the wavelength width of λ2.1 to λ2 adjacent to this is converted.
The variable wavelength width of +m is converted by the wavelength conversion element W2. Here, the adjacent wavelengths λl+l of the two wavelength conversion elements W, , W2
I and λ2.1 are assumed to be the same wavelength. In this way,
n wavelength conversion elements W1, W having adjacent variable wavelength widths
2,..., Wfi is connected in multiple stages to λl, I~λ. +
Covers lI.

For example, consider the case where an input optical signal with wavelength λl+l is converted into an output optical signal with wavelength λ3.4. In this case, first, wavelength λ11. into an optical signal. λ
11. = λ2,1, the wavelength conversion element W2 is connected after the wavelength conversion element W1 (thereby, the output signal of the wavelength λ1.□ of the wavelength conversion element W1 is converted by the wavelength conversion element W2 to It can be converted into an optical signal. Furthermore, by connecting the wavelength conversion element W3 after the wavelength conversion element W2, the output optical signal of λ2, 3 of the wavelength conversion element W2 (λ2 = λ3, 1) can be converted into an optical signal. Wavelength λ3 at W3
, 4.

In this way, by connecting adjacent wavelength conversion elements with variable wavelength widths in multiple stages, the wavelengths can be converted in sequence, and an input optical signal can be converted to an arbitrary wavelength.

Below, we will discuss the case of one-to-one wavelength conversion (■) in which an input optical signal with a fixed wavelength is converted into an optical signal with an arbitrary wavelength, and the case of one-to-one wavelength conversion in which an input optical signal with an arbitrary wavelength is converted into an optical signal with a fixed wavelength or n types. 1:1 or 1:n to convert into optical signal of wavelength
In the case of wavelength conversion (■), converting an input optical signal of any wavelength to an optical signal of any one wavelength or n different wavelengths, which targets wavelength-division exchange of multiple wavelength-multiplexed input highways. In the case of pair-to-one or one-to-n wavelength conversion (■
), the configurations of wavelength conversion elements connected in multiple stages will be explained with reference to FIGS. 4 to 6, respectively.

FIG. 4 is a configuration diagram of a wavelength conversion switch in the case of one-to-one wavelength conversion (■) in which a manually-powered optical signal of a fixed wavelength is converted into an optical signal of an arbitrary wavelength.

The wavelength conversion switch has wavelengths λ1,1 to λ. a splitter 41 that divides an input optical signal 40 in which the signals of 1 and 1 are wavelength-multiplexed into optical signals corresponding to the number of wavelength multiplexes, a wavelength selection section 42 that selects the wavelength of the input optical signal, a wavelength conversion section 43 that converts the wavelength,
It consists of a coupler 44 that wavelength-multiplexes the converted optical signal and outputs it as an output optical signal 45.

In case (2), since the wavelength of the optical signal input to the wavelength converter 43 is fixed, the wavelength selector 42 splits the optical signal into optical signals corresponding to the wavelength multiplicity by the splitter 41 with variable wavelength width W + (λ1.1~λ1.□)W2(λ2,1~λ2
,1),...,Wo (λ.

~λ7. n wavelength selection filters Sλ (42-1, 42-2, . . . , 42-n) that distribute signals with a wavelength width of
).

The optical signal selected by the wavelength selection filter Sλ is sent to the wavelength converter 4
3 is input. The wavelength conversion unit 43 has a configuration in which a plurality of wavelength conversion elements are connected in multiple stages.

λ1,1 to λ1 selected by the wavelength selection unit 42-1
1. In the case of an optical signal having a wavelength of , it is first input to the wavelength conversion element 43-1-1 having a variable wavelength width W1.

The wavelength conversion element 43-1-1 converts the input optical signal into a variable wavelength width W.
can be converted to a wavelength within the range of 1. Wavelength conversion element 43
The output of -1-1 is connected to the next stage wavelength conversion element 43-1-2 via a switch 46-11. Wavelength conversion element 4
3-1-2 has a variable wavelength width W2 adjacent to the variable wavelength width W1 of the wavelength conversion element 43-1-1. Furthermore, in the third stage, there is a wavelength conversion element 43-13 having a variable wavelength width W3, and so on up to the n-th stage wavelength conversion element 43-1n.
wavelength conversion elements are connected.

A switch is arranged between adjacent wavelength conversion elements. The switch switches the input of the signal to the wavelength conversion element in the next stage and the input of the output signal of the wavelength conversion element in the previous stage to the combiner 44.

For example, when converting an input signal with a wavelength λ1,1 to a wavelength λ3.4, the signal with a wavelength λ1,1 selected by the wavelength selection filter 42-1 is transmitted to the wavelength conversion element 43-1-1 (variable wavelength width W1 ), first, the longest wavelength λ11 . is converted to The converted signal is sent to switch 46
-1-1 to the second stage wavelength conversion element 43-1-2
(variable wavelength width W2), and again the variable wavelength width W
2's longest wavelength λ2. .

The signal is converted into a wavelength conversion element 43-1-3 (variable wavelength width W3) at the third stage via a switch 46-1-2. Since the desired wavelengths λ3 and 4 are within the range of the variable wavelength width w3, the wavelength conversion element 43-1-3 converts the input signal (wavelength λ21.) to the wavelength λ1.4 and outputs it.

Since the conversion to the desired wavelength is completed, the output signal is input to the coupler 44 via the switch 46-1-3.

λ2,1 to λ2 selected by the wavelength selection unit 42-2
In the case of an optical signal with a wavelength of +m, the first stage of the wavelength converter 43 has λ21. ~λ2. . A wavelength conversion element (Wl) having a variable wavelength width is arranged. Then, it is connected to the next stage wavelength conversion element via the switch 46-2-1.

In the case of the variable wavelength width W2, there are two adjacent variable wavelength widths (the same applies to the case of W:l, Wa, . . . , W,, -1). That is, Wl and Wl.

Therefore, in the second stage, a wavelength conversion element 43-2-2 (tunable wavelength width W1) and a wavelength conversion element 43-2-3 (tunable wavelength width W3) are connected in parallel (the first stage has a variable wavelength width W3). In the case of a wavelength conversion element, the second stage includes two wavelength conversion elements in parallel, one on the short wavelength side and the other on the long wavelength side adjacent to the variable wavelength width of the first stage, such as a variable wavelength width W2 and a variable wavelength width W4. ).

That is, the switch 46-2-1 connected to the first stage wavelength conversion element 43-2-1 (variable wavelength width W2) sends the output of the wavelength conversion element 43-2-1 to the coupler 44. , the input to wavelength conversion element 43-2-2 (variable wavelength width WI), and the input to wavelength conversion element 43-2-3 (variable wavelength width W3).

From the third stage onwards, the wavelength conversion element on the short wavelength side of the second stage is further connected to the wavelength conversion element on the short wavelength side via a switch, and the wavelength conversion element on the long wavelength side of the second stage is connected to the wavelength conversion element on the short wavelength side of the second stage. further connects a wavelength conversion element on the longer wavelength side via a switch.

The second stage is a wavelength conversion element 43-2-2 (variable wavelength width Wl
), since there is no adjacent wavelength on the short wavelength side, the output of the wavelength conversion element 43-2-2 (variable wavelength width W+) becomes the input of the coupler 44.

On the other hand, wavelength conversion element 43-2-3 (variable wavelength width w3)
In the case of , there is an adjacent wavelength on the long wavelength side, so
The output of the wavelength conversion element 43-2-3 is connected to the switch 46-2.
-3 to the next stage (third stage) wavelength conversion element 43-2.
-4 (variable wavelength width W4), and similarly, the n-th
Wavelength conversion elements 43-2-5, 43-2-6, . . . 43' having a variable wavelength width W adjacent to the long wavelength side up to the first stage.
-2-n is connected.

A switch is placed between adjacent wavelength conversion elements, and switches the output of the previous wavelength conversion element to be input to the next wavelength conversion element or to the coupler 44.

For example, wavelength λ29. The signal on the short wavelength side wavelength λ1,1
When converting into
1 (tunable wavelength width W2) and adjacent wavelength λ2+ on the short wavelength side
l (=λ; 1.), and the converted signal is passed through the switch 46-2-1 to the wavelength conversion element 41-2-2 (
input into the variable wavelength width wL). Wavelength conversion element conversion element 4
3-2-2 (variable wavelength width W+) after converting into wavelengths λ1 and 3, the output is passed to the coupler 44.

On the other hand, the signals with wavelengths λ2 and 5 have wavelengths within the same variable wavelength width,
For example, when converting to λ2.1, a signal with wavelength λ2.5 is converted to wavelength conversion element 43-2-1 (variable wavelength width Wz).
It is sufficient to convert the signal into λ2,1 and output it to the coupler 44 via the switches 46 to 2-1.

A signal with a wavelength of λ2.5 is converted into a signal on the longer wavelength side, for example, λ4,2.
When converting to λ2., the longest wavelength λ2. of the variable wavelength width w2 is converted in the first stage. ．． (−λ3.1). Since λ4.2 is a wavelength within the variable wavelength width W4, the wavelength conversion element 43-
2-3 (tunable wavelength width W3) longest wavelength λ3.1. l(
”'λ4.I), and the third stage wavelength conversion element 43
-2-4 Input to (variable wavelength width W4). The wavelength conversion element 43-2-4 converts the signal of λ1,1 into a wavelength of λ4,2, which is input to the coupler 44 via the switch 46-2-4.

The wavelength selection unit 42-n selects the longest variable wavelength range λ1.1 to λ01. of this wavelength conversion switch. When the wavelength power is selected, the wavelength conversion elements (W,, w, , . . . , W,) are connected in order from the wavelength conversion element with the variable wavelength width of the long wavelength. A switch (46
-n-1,...46-n-(n-1)),
With the switch, it is possible to select whether the output of the previous stage wavelength conversion element is input to the next stage wavelength conversion element or to the coupler 44.

As described above, adjacent wavelength conversion elements are sequentially connected in multiple stages,
By placing a switch between wavelength conversion elements and distributing output signals, it becomes possible to convert an input optical signal of a fixed wavelength into a signal of an arbitrary wavelength.

Figure 5 shows how an input optical signal of an arbitrary wavelength is converted to a fixed wavelength (one wavelength or n wavelengths), and one-to-one or one-to-n wavelengths are converted.
FIG. 2 is a configuration diagram of a wavelength conversion switch in the case of performing wavelength conversion (■).

The wavelength conversion switch has a wavelength of λ2,1~! ,,,,(7)
A branching device 51 that divides an input optical signal 50 in which a signal is wavelength-multiplexed into optical signals corresponding to the number of wavelength multiplexed signals, a wavelength selection section 52 that selects the wavelength of the input optical signal, a wavelength conversion section 53 that converts the wavelength, and a converted light It consists of a coupler 54 that wavelength-multiplexes signals and outputs them as an output optical signal 55.

In case (2), the wavelength of the optical signal input to the wavelength converter 53 is arbitrary, and the wavelength of the output signal of the wavelength converter 53 is fixed.
The signal input to the coupler 54 is λ1.1 to λl+lI
(w+), λ2+I ~ λz, -(W2)...
・λ1. ．． ~λ. , , (Wn). On the other hand, since the wavelength of the input signal is arbitrary, a switch is placed at the input end of the wavelength conversion elements connected in multiple stages so that the input signal can be input to any wavelength conversion element.

Desired output signal wavelength is λ1.1~λ+,,,(W+)
In this case, wavelength conversion elements having variable wavelength widths of long wavelengths are connected in order from the first stage, and a switch is placed at the input section of each wavelength conversion element. That is, the wavelength conversion elements 5 are sequentially applied from the first stage.
3-1-1 (Variable wavelength width wfi) Wavelength conversion element 53-
1-2 (tunable wavelength width wn-1), ..., wavelength conversion element 53-1- (n-1) (tunable wavelength width W2), wavelength conversion element 53-1-1 (tunable wavelength width W1) Connecting. Then, switches (56-1-1, 56-1-2, . . . , 56-1-
(n-1)).

For example, if the wavelength of the input optical signal is λn-1+3 and it is to be converted to the wavelength λn-5, the input optical signal is A n
It is first input to the wavelength conversion element 53-1-2 of variable wavelength width Wn-, which includes -1 and -3.

At this time, switch 56-1-1 and switch 56-1
-2 to the wavelength conversion element 53-1-2.

The signal input to the wavelength conversion element 53-1-2 (variable wavelength width Wn-+) is sequentially converted to shorter wavelengths in order to finally convert to wavelengths λ1 and 5. First, the wavelength conversion element 53-1-2 converts the shortest wavelength λrl-l+1 (=λn-2) of the variable wavelength width Wn-1, and inputs it to the next stage wavelength conversion element 53-1-3. Finally, the wavelength conversion element 53-1-n converts the wavelength to the shortest wavelength.
+ (=λl, . . .) is converted to a wavelength of λ1.5, and the output signal of the conversion section is input to the coupler 54.

Further, the desired output signal wavelength is λ2,1 to λ2. Yo (W2
), the variable wavelength width of the final stage wavelength conversion element 53-2-n becomes W2. In the preceding stage, there is a wavelength conversion element 53-2-(n-1) (variable wavelength width WI) on the shorter wavelength side, and a wavelength conversion element 53-2 on the longer wavelength side.
- (n-2) (variable wavelength width W3) are connected in parallel.

The desired conversion wavelength is variable wavelength width W2, W3,..., Wfi
In the case of wavelengths within the range of -1, generally two wavelengths having variable wavelength widths on the short wavelength side and long wavelength side adjacent to the variable wavelength width of the final stage wavelength conversion element are installed in the previous stage of the final stage. Connect the conversion elements in parallel.

Then, the wavelength conversion element on the short wavelength side is connected with a wavelength conversion element with a shorter wavelength toward the front stage, and the wavelength conversion element with a long wavelength side is connected with a wavelength conversion element with a longer wavelength toward the front stage. Connect the elements.

Switches (56-21, 56
-2-2, ... 56-2-(n-2)), the input optical signal can be input to any wavelength conversion element.

The desired eight-power signal wavelength is λ. , 1 to λfl+lIn, the wavelength width W is variable from the final stage to the previous stage. ,W
, -1, ..., Wl, connect the wavelength conversion elements in the order of 5.
3-n-n, 53-n-(n-1),...53-n-
1) Place a switch at the input part of each wavelength conversion element,
Enables input signals to be input to any wavelength conversion element.

By connecting wavelength conversion elements and switches in multiple stages in this manner, an input optical signal of any wavelength can be converted to a fixed wavelength or n fixed wavelengths.

For example, using this wavelength conversion switch, the wavelength λ4.5
One-to-one wavelength conversion converts the input signal of wavelength λ2, 3 to wavelength λ4. ．． The input signal of wavelength λ1.1λ2.1,
..., 1:n wavelength conversion into n wavelengths of λ7,1 is possible.

Figure 6 shows a one-to-one or one-to-one pair system that converts an input optical signal of any wavelength into an optical signal of any one wavelength or n types of wavelengths, targeting wavelength division type switching of multiple wavelength-multiplexed input highways. FIG. 3 is a configuration diagram of a wavelength conversion switch in the case of wavelength conversion of n (■);

The wavelength conversion switch includes a splitter 61 that divides an input optical signal 60 in which signals of wavelengths λ1,1 to λ7.1 are wavelength-multiplexed into optical signals corresponding to the number of wavelength multiplexed signals, and a wavelength selection unit that selects the wavelength of the input optical signal. 62, wavelength conversion unit 63 that converts wavelength;
It consists of a coupler 64 that wavelength-multiplexes the converted optical signal and outputs it as an output optical signal 65.

In case (2), the wavelength of the optical signal input to the wavelength converter 62 is arbitrary, and the wavelength of the optical signal output from the wavelength converter 62 is also arbitrary. Therefore, the wavelength conversion elements of the wavelength conversion switch are sequentially arranged from the short wavelength side to the long wavelength side from the first stage.
It is sufficient to connect wavelength conversion elements having adjacent variable wavelength widths. That is, the first stage is a wavelength conversion element 63-1 having a variable wavelength width WI, and the next stage is a wavelength conversion element 6 having a variable wavelength width W2.
3-2, . . . , the final stage is a wavelength conversion element 63-n having a variable wavelength width Wn.

In order to set both the manual wavelength and the output wavelength to arbitrary wavelengths, a switch is provided at the input section and output section of each wavelength conversion element. That is, each wavelength conversion element 63-k
(k=1.2,...,nl) has a switch 6 at the input section.
6-'k -1, -0 is placed in the switch 66- in the output section.

The switch 66-1 at the input section is the wavelength conversion element 63.
-k, or switch 66-(k+1) at the input of the next stage wavelength conversion element 63-(k
This is a switch that determines whether to send a signal to +1)-1.

On the other hand, -0 for the switch 66- in the output section determines whether the output signal from the wavelength conversion element 63- is passed to the coupler 64, inputted to the next stage wavelength conversion element 637 (k+1), or This is a switch that determines whether to input the signal to the wavelength conversion element 63-(k-1) in the previous stage.

By configuring the wavelength conversion switch in this way,
Any wavelength, for example, converting a signal of wavelength λ4, 5 to any wavelength,
For example, 1:10 wavelength conversion to convert to a signal of λ7,8,
Signals of arbitrary wavelengths, for example wavelengths λ4, 5, can be converted to λ1,1, λ
2, 1, ..., λ. , 1 to n wavelength signals is possible. Since the wavelength of the input signal can be set arbitrarily, it is possible to configure an optical switching wavelength conversion switch that receives a plurality of input highways as inputs.

FIG. 7 shows the wavelength conversion switch in each case of ■, ■, and ■ explained in FIGS. 4 to 6, with the wavelength multiplicity number n='
7 is a configuration diagram of a wavelength conversion switch.

FIG. 7(a) is a diagram showing the relationship between input and output wavelengths of the wavelength conversion element.

The multiplexed wavelengths are λ1, λ2, ... λ7, and the wavelength conversion element is a variable wavelength width Wt (λ1 to λ3) and a variable wavelength width Wt.
z (λ3 to λ5), variable wavelength width W3 (λ, to λ7)
wavelength conversion elements are used.

FIG. 5B is a configuration diagram of a wavelength conversion switch in the case (2), that is, the wavelength of the input optical signal is fixed and the wavelength of the output signal is arbitrary one-to-one wavelength modulation.

First, an input optical signal 70 obtained by wavelength multiplexing signals with wavelengths λ1 to λ7 is split into seven signals by a splitter 71, and a variable wavelength width W
1. Wavelength selection filter 72 for selecting Wl, Wl
-1.72-2.72-3. The wavelength-selected optical signal is input to the wavelength converter, and the output of the wavelength converter is wavelength-multiplexed by a coupler 74 and output as an output optical signal 75.

For signals with wavelengths λ1 and λ2 corresponding to the variable wavelength width W1, the wavelength conversion elements are connected to Wl, Wl, Wl (73-1-1
, 73-1-2, 73-1-3), and optical switches (76-1-1, 76-1-2) are connected between wavelength conversion elements W1 and Wl and between Wl and Wl. Deploy.

By arranging the wavelength conversion elements and optical switches in this way, signals with wavelengths λ1 and λ2 can be converted into arbitrary signals with wavelengths λ and λ7. That is, when the desired wavelength is λ1 or λ2, the output of the first-stage wavelength conversion element W1 is taken out via the optical switch 76-1-1, and the output from the coupler 7
Enter 4.

Further, when the desired wavelength is between λ3 and λ5, first, the wavelength conversion element W in the first stage converts the wavelength of the input signal to λ3, and the wavelength conversion element W2 in the next stage converts the wavelength to λ3 via the optical switch 76-1-1.
The wavelength is converted to a desired wavelength of λ3 to λ5. Then, the output is taken out via the optical switch 76-1-2 and input to the coupler 74. Finally, if the desired wavelengths are λ6 and λ7,
The wavelength conversion element W2 in the second stage converts the wavelength of the input signal to λ5, and this signal is input to the wavelength conversion element W3 via the optical switch 76-1-2. Or convert it to λ7.

λ3 to λ, where the wavelength of the input signal corresponds to the variable wavelength width W2,
In the case of the wavelength, the wavelength conversion element 7 with the variable wavelength width W2
3-2-1 is placed in the first stage (.In the next stage, a wavelength conversion element 73 of variable wavelength width Wl and Wl adjacent to variable wavelength width W2 is installed.
-2-2.73-2-3 are connected in parallel. On the output side of the wavelength conversion element W2, the output is input to the coupler 74,
A switch 76-2-1 is inserted to determine whether to input the signal to the next stage wavelength conversion element (W+ or Wl). Also, the second
In the input part of the wavelength conversion element (W+ or Wl) of the stage,
A switch 76-2-2 is inserted to determine which wavelength conversion element, W or Wl, to which a signal is input.

By connecting the wavelength conversion element and the switch in this way, an input signal with a wavelength of λ3 to λ can be converted to a signal with an arbitrary wavelength of λ to λ.

For input signals of wavelengths λ6 and λ7, wavelength conversion elements are connected in the order of Wl, Wz, W'+, and an optical switch 76-3 is connected between wavelength conversion elements W3 and Wz and between w2 and Wl. -1 and 76-3-2 are inserted. This allows the input signals of wavelengths λ6 and λ7 to be
can be converted to a signal of any wavelength.

FIG. 4(c) is a configuration diagram of a 1:1 or 1:n wavelength conversion switch in the case (2), in which the input signal wavelength is arbitrary and the output signal wavelength is fixed.

In case (2), since the output signal wavelength is fixed, the wavelength of the signal input to the coupler 74 is fixed. For this reason, a wavelength conversion element having a fixed variable wavelength width is arranged as a wavelength conversion element at the final stage of the wavelength conversion section.

That is, a wavelength conversion element 93-1-3 having a variable wavelength width W1 is placed at the final stage of the wavelength conversion switch that obtains output signals of wavelengths λ1 and λ2, and a wavelength conversion element W2 (93-1-3) is placed at the previous stage.
312), the wavelength conversion element W3 (9311) is connected to the first stage. Then, an optical switch is arranged at the input section of each wavelength conversion element so that an input signal of an arbitrary wavelength can be input to the wavelength conversion element (96-1-1 and 96-1-2).

Further, in order to obtain output signals of wavelengths λ, to λ5, a wavelength conversion element W2 (93-2-2) is placed at the final stage. In the preceding stage, a variable wavelength width W1 adjacent to the variable wavelength width W2 is provided.
and wavelength conversion element 93-2-1.93-2 with Wl
-3 are connected in parallel.

Then, an optical switch 96-2-1 is installed at the input part of the wavelength conversion element Wz and the input parts of the wavelength conversion elements W1 and W3 so that an input signal of any wavelength can be input to the wavelength conversion element.
．． Place 96-2-2.

Finally, in order to obtain output signals of wavelengths λ6 and λ7, a wavelength conversion element W3 (9333) is placed at the final stage. The wavelength conversion element W2 is connected to the front stage thereof, and the wavelength conversion element Wl is connected to the front stage thereof.

In addition, an optical switch 96-3 is connected to the input part of the wavelength conversion element W+.
-1, optical switch 96-3 at the input part of wavelength conversion element W2
Place -2.

The optical switch 96-3-1 converts the input signal into a wavelength conversion element W.
This is an optical switch that determines whether to input the signal to the wavelength conversion element in the next stage or later. In addition, the optical switch 96-
3-2 is an optical switch that determines which of the wavelength conversion elements W2 and W3 the input signal input from the optical switch 96-3-1 is input to.

By connecting the wavelength conversion element and the optical switch as described above, an input signal of any wavelength can be converted to a desired wavelength. For example, in the case of one-to-one wavelength conversion in which an input signal of λ2 is converted to λ6, the output of the wavelength selection filter 72-3 is passed through the optical switch 96-3-1 to the wavelength conversion element W.
+ (93-3-1), converted to wavelength λ3,
Next, the signal is converted to wavelength λ5 by wavelength conversion element W2 (9332), and further converted to wavelength λ5 by wavelength conversion element W3.
(9333), it is converted to wavelength λ6.

Further, for example, a 1-to-n conversion that converts an input signal of λ2 to λ1 to λ is also possible with the wavelength conversion switch having this configuration. That is, regarding the output signals λ1 and λ2, the output signal (wavelength λ2) of the selection filter 72-1 is transmitted to the optical switch 9.
Wavelength conversion element W+ via 6-1-3.961-2
(9311), converted into wavelengths λ1 and λ2,
For the output signals λ3 to λ, the selection filter 72-2
The output signal (wavelength λ2) is sent to the wavelength conversion element W via optical switches 96-2-1 and 96-2-2.

(93-2-2), and after being converted to a wavelength of λ3, the wavelength conversion element wz (93-2-1) converts λ3 to λ.
5 wavelength. In addition, regarding the output signals λ6 and λ7, the output signal (wavelength λ2) of the selection filter 72-3
is the wavelength conversion element W, (
93-3-3), is converted to wavelength λ3, and is input to wavelength conversion element Wz (9332) to have wavelength λ5.
In addition, the wavelength conversion element W3 (933-
1), it is converted into wavelengths of λ6 and λ7. By doing so, 1:n wavelength conversion is possible.

FIG. 3(d) is a configuration diagram of the wavelength conversion switch in the case (2), that is, when both the input signal and the output signal are arbitrary.

Similarly to FIGS. 3A to 3C, an input optical signal 70 is branched into optical signals corresponding to the number of wavelength divisions by a splitter 71, and a wavelength selection filter 72 selects the wavelength of each branched optical signal. The wavelength of the wavelength-selected optical signal is converted by a wavelength conversion element, and then wavelength-multiplexed again by a coupler 74 to produce an output optical signal 7.
Output as 5.

In the case of (2), both the input and output signal wavelengths are arbitrary, so the wavelength conversion elements are arranged in order from the one with the lowest variable wavelength width to the wavelength conversion element W +
, Wz, and W3 in this order (103-1.103
-2.103-3). Optical switches are placed at the input and output parts of each wavelength conversion element. An optical switch 106-1-I is placed at the input part of the wavelength conversion element W1, and it is determined whether the input signal is input to the wavelength conversion element W1 or to the next stage wavelength conversion element (Wz or W3). switch. Further, an optical switch 106-1-0 is placed at the output part of the wavelength conversion element Wl, and it is determined whether the output of the wavelength conversion element W1 is input to the coupler 74 or to the next stage wavelength conversion element W2. switch.

An optical switch 106-2- is provided at the input part of the wavelength conversion element W2.
1 and input the input signal to the wavelength conversion element W2, or
This is a switch that determines whether to send the signal to the next stage wavelength conversion element. Also, on the output side, first, an optical switch 106-2-01
is used as a switch that determines whether or not to feed back the output signal of the wavelength conversion element W2 to the preceding wavelength conversion element W.

If it does not return, the next optical switch 106-. 2-0
2 to the coupler 74 or the next stage wavelength conversion element W3
Decide what to enter.

Optical switches 106-3-1 and 106-3-0 are also placed at the input and output parts of the wavelength conversion element W3, respectively. The optical switch 106-3-1 is a switch that determines whether or not to input the output signal of the selection filter 72 to the wavelength conversion element W3, and the optical switch 106-3-0 inputs the output signal of the wavelength conversion element W3. This is a switch that determines whether the signal is fed back to the wavelength conversion element W2 at the previous stage or input to the coupler 74.

By configuring the wavelength conversion switch in this way, it is possible to convert an input signal of any wavelength to any wavelength.

For example, the wavelength λ1 can be converted to any or all of the wavelengths λ2 to λ. The former is 1:1 wavelength conversion, and the latter is 1:n wavelength conversion.

When the wavelength of the input signal is λ or λ2, it is first input to the wavelength conversion element W+. Set the output wavelength to λ1 or λ
2, the output is input to the coupler 74 via the optical switch 106-1-0. On the other hand, the output wavelength is λ3~
When converting λ5, the wavelength is converted to λ by the wavelength conversion element Wl.
3, input it to the wavelength conversion element W2, and convert it to λ3~
It is converted into a wavelength of λ5 and output to the coupler 74. Further, when converting the output signal wavelength to λ6 or λ7, the signal input to the wavelength conversion element W2 is converted to the wavelength λ.

The wavelength is converted into a wavelength of λ6 or λ7, and then input to the wavelength conversion element W3, where the wavelength is converted to a wavelength of λ6 or λ7.

On the other hand, if the input wavelength is λ3 to λ5, or λ6, λ
In the case of 7, the input signal is first input to the wavelength conversion element W2 and the wavelength conversion element W3, respectively.

If the desired output has a wavelength on the short wavelength side, the output is fed back to the preceding wavelength conversion element via an optical switch to convert the wavelength. When converting the wavelength to a longer wavelength side, a signal is input to a subsequent wavelength conversion element and converted.

By employing the three wavelength conversion switch configuration methods as described above, wavelength conversion is possible in all cases.

[Effects of the Invention] According to the present invention, by configuring a wavelength conversion switch by connecting wavelength conversion elements with different variable wavelength widths in multiple stages,
It becomes possible to widen the overall variable wavelength width, and it becomes possible to increase the degree of wavelength multiplexing. Further, the variable wavelength width of each wavelength conversion element connected in multiple stages can be small, that is, the required characteristics of each wavelength conversion element can be relaxed. By connecting wavelength conversion elements with less demanding characteristics in multiple stages, it becomes possible to configure a large-scale wavelength conversion switch.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the present invention, Fig. 2 is a system configuration diagram of one embodiment, Fig. 3 is a relational diagram of the input/output wavelength width of the wavelength conversion element, and Fig. 4 is a diagram of the principle of the present invention (1). (Wavelength selection section (fixed) - wavelength conversion section (optional)), Figure 5 is a principle diagram of the present invention (2) (wavelength selection section (optional) -
Figure 6 is a diagram of the principle of the present invention (3) (wavelength selection unit (optional)).
FIG. 7 shows a configuration example of a wavelength conversion switch (in the case of n=7), and FIG. 8 shows a wavelength conversion switch with a conventional configuration. DESCRIPTION OF SYMBOLS 1... Wavelength multiplexing input signal, 2... Wavelength selection part, 3... Selected wavelength signal, 4... Wavelength conversion part, 5... Wavelength multiplexing multiplexer, 6... Wavelength multiplexing output Signal, 7... Wavelength conversion switch, 8... Wavelength conversion means.

Claims (1)

[Claims] 1) A wavelength selection unit (2) consisting of a plurality of selection filters (selection filter 1(
2-1), selection filter 2 (2-2), ..., selection filter n (2-n)), and optical signals (3) (3-1, 3-2) selected by each selection filter. ,...,3-n
), and a wavelength multiplexer (5) that multiplexes the converted optical signals to generate a wavelength multiplexed output signal (6). In the conversion section (4), wavelength conversion means (8) converts the wavelength of each selected optical signal (3-1, 3-2, . . . , 3-n) using a plurality of wavelength conversion element groups connected in multiple stages. (8-1, 8-2,..., 8-n)
A wavelength conversion switch configuration method characterized by having the following. 2) The wavelength conversion means (8) (8-1, 8-2,...
, 8-n) are each selected optical signal (3-1, 3-2, . . .
, 3-n), a plurality of wavelength conversion elements with different variable wavelength widths are connected in multiple stages so that the output of the wavelength conversion element in the previous stage and the wavelength width of the input of the wavelength conversion element in the next stage are the same. The wavelength conversion switch configuration system according to claim 1, wherein the wavelength of the selected optical signals (3-1, 3-2, . . . , 3-n) is converted. 3) The wavelength conversion means (8) (8-1, 8-2,...
, 8-n) are respectively selected optical signal inputs (3-1, 8-n).
A wavelength conversion element corresponding to 3-2, ..., 3-n) is arranged at the first stage, and a wavelength conversion element (two or one) having a variable wavelength width adjacent to the variable wavelength width of the wavelength conversion element. Connect to the next stage (if 2 are installed, connect 2 in parallel)
In the third and subsequent stages, wavelength conversion elements with variable wavelength widths adjacent to the previous stage are connected (if two wavelength conversion elements are arranged in parallel in the second stage, the shortest of the two wavelength conversion elements A wavelength conversion element with a variable wavelength width adjacent to the short wavelength side is connected to the element on the wavelength side from the third stage onwards, while a wavelength conversion element with a variable wavelength width adjacent to the long wavelength side is connected to the element on the long wavelength side from the third stage onwards. A switch is provided at the output of the wavelength conversion element in each stage so that the output light can be taken out from any element, and each selected optical signal with a fixed wavelength (3-1, 3 -2
, . . . , 3-n) to an arbitrary wavelength. 4) The wavelength conversion means (8) (8-1, 8-2,...
, 8-n), a wavelength conversion element with a variable wavelength width corresponding to the output signal light of a fixed wavelength is arranged in the final stage of a group of wavelength conversion elements connected in multiple stages, and Connect wavelength conversion elements (two or one) with a variable wavelength width adjacent to the variable wavelength width of the conversion element (when connecting two, connect them in parallel), and then perform wavelength conversion from the previous stage to the first stage. As an element, a wavelength conversion element with a variable wavelength width adjacent to the wavelength conversion element in the latter stage is connected to the previous stage (if two wavelength conversion elements are arranged in parallel before the final stage, two wavelength conversion elements are connected in parallel). As a wavelength conversion element from the front stage to the first stage of the element on the short wavelength side of the element, a wavelength conversion element with a variable wavelength width adjacent to the short wavelength side is connected, and on the other hand, the wavelength conversion element from the front stage to the first stage of the element on the long wavelength side is connected. A wavelength conversion element with a variable wavelength width adjacent to the long wavelength side is connected as an element), and a switch is provided at the input section of each wavelength conversion element to enable input of any input light, so that the wavelength of the input signal light can be changed. 2. The wavelength conversion switch configuration system according to claim 1, wherein one-to-one and one-to-n wavelength conversion is optionally performed with a fixed wavelength of the output signal light. 5) The wavelength conversion means (8) (8-1, 8-2,...
, 8-n), the waveform conversion elements are connected in order from the wavelength conversion element with the variable wavelength width on the short wavelength side, and switches are provided at the input and output parts of each wavelength conversion element, so that arbitrary An input signal light can be input to a wavelength conversion element, and an output signal light can be output from an arbitrary wavelength conversion element,
Furthermore, by making it possible to input the output light of each waveform conversion element as the input light of the wavelength conversion element on the short wavelength side in the previous stage and allowing it to be fed back from the element on the long wavelength side to the element on the short wavelength side, wavelength multiplexing is achieved. One-to-one and 2. The wavelength conversion switch configuration system according to claim 1, which performs 1:n wavelength conversion.