JPH03101584A - Optical channel device of wavelength split type - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the S/N at a receiver side by converting a wavelength of a signal light with a wavelength conversion switch to prevent an input signal light from being mixed in an output signal light outputted to an output highway. CONSTITUTION:Optical signals whose wavelengths are lambda1, lambda2, to lambdan subject to multiplex sent from an input highway 11 are demultiplexed by a demultiplexer 13, fed to a 1st wavelength conversion switch 15a, in which the wavelengths lambda1,lambda2, to lambdan are converted into wavelengths lambda1', lambda2', to lambdan' different from the wavelengths lambda1, lambda2, to lambdan respectively and sent to a 2nd wavelength conversion switch 15b from the 1st wavelength conversion switch 15a. Then the wavelengths lambda1', lambda2', to lambdan' are converted into the wavelengths lambda1, lambda2, to lambdan at the 2nd wavelength conversion switch 15 and sent to a multiplexer 14.

Description

[Detailed description of the invention] Industrial field of application Conventional technology (Fig. 4) Means for solving the problem to be solved by the invention (Fig. 1) Effect (Fig. 1) Example 1 Description of the embodiment (Fig. 2) Description of the second embodiment (Fig. 3) Effects of the invention [Summary] In optical exchange, in which optical information from an optical fiber transmission line is exchanged as light, information is exchanged according to the wavelength of the light. Regarding a wavelength-division optical communication path device for switching, the input signal light is converted by a wavelength conversion switch to the output signal light that is output to the output highway while keeping the wavelengths of the signal lights on the input and output highways the same. In a wavelength-division optical communication path device that accommodates wavelength-multiplexed input and output highways and performs switching by changing the input wavelength multiplexing order by performing wavelength conversion, the input highway signal The first converts each wavelength of light into a wavelength different from any of these and outputs it.
and a second wavelength conversion switch that converts the output signal light from the first wavelength conversion switch back to the wavelength of the input highway signal light and outputs it to the output highway.

[Industrial Application Field] The present invention relates to a wavelength-division optical channel device for switching information according to the wavelength of light in optical exchange in which optical information from an optical fiber transmission line is exchanged as light.

As such a wavelength division type optical channel device, one has been developed that accommodates wavelength-multiplexed input/output highways and performs switching by performing wavelength conversion and changing the input wavelength multiplexing order. A wavelength conversion switch is required, and how to configure it is important.

[Prior Art] Fig. 4 is a block diagram showing a conventional example. In Fig. 4, 4 accommodates a wavelength-multiplexed traffic highway and performs wavelength conversion to change the order of input wavelength multiplexing. This is a wavelength division type optical communication path device that performs switching by switching.

Reference numerals 11 and 12 designate an input highway and an output highway that are wavelength-multiplexed, and in this example, four types of optical signals with wavelengths λ1 to λ are wavelength-multiplexed on the input highway 11 and the output highway 12.

Reference numeral 13 denotes a demultiplexer (wavelength demultiplexer: WDMUX) that demultiplexes each wavelength-multiplexed optical signal with wavelengths λ□ to λ, and 14 denotes a multiplexer that multiplexes each demultiplexed optical signal with wavelengths λ1 to λ. It is a wavelength multiplexer (WMUX).

20 is a wavelength conversion switch (WSW) that performs switching by performing wavelength conversion on each optical signal with wavelengths λ□ to λ4 and changing the multiplexing order of input wavelengths;
A wavelength conversion element W□ converts an optical signal with a wavelength λ1 into an optical signal with a wavelength λ1, a wavelength conversion element W2 converts an optical signal with a wavelength λ into an optical signal with a wavelength λj, and a wavelength conversion element W2 converts an optical signal with a wavelength λ into an optical signal with a wavelength λj. a wavelength conversion element W that converts into an optical signal of wavelength λ;
a wavelength conversion element W that converts an optical signal of wavelength λl into an optical signal of wavelength λl.
It is composed of 4.

Semiconductor lasers are generally used as these wavelength conversion elements Wi to W4.

In addition, "tJykl12 is any one of 1 to 4, and wavelength λ1.For λJ, λ, λi is selected from the wavelengths λ and ~λ4 of the input signal light, respectively, without duplication. This is what I did.

With such a configuration, each of the multiplexed optical signals of wavelengths λ1 to λ is sent from the input highway 11 to the demultiplexer 13, and after being demultiplexed by the demultiplexer 13.

Each wavelength conversion element W□, W2゜W of the wavelength conversion switch 20
3. At W4, the wavelength λ□ is the wavelength λ1, and the wavelength λ2 is the wavelength λ
j, the wavelength λ becomes the wavelength λk, the wavelength λ4 becomes the wavelength λi,
These wavelengths λl, λj,
At λ, the optical signals at λ are multiplexed by a multiplexer 14 and sent to the output highway 12.

[Problems to be Solved by the Invention] However, in such a conventional wavelength division type optical communication channel device, - In a fishing boat, a wavelength conversion element using a semiconductor laser is used.
,, w,, w,, w, when the wavelength is converted by λ1. λ2. λ1. The input signal lights of λ1 (indicated by dotted arrows in FIG. 4) have respective converted wavelengths λ1.
The characteristics of λj and λ that mix into the 1st base 8-power signal light (
There is so-called crosstalk).

Therefore, if the wavelengths on the input and output highways are set to the same size, the wavelength conversion element W2 t w, t
There is a problem in that the W4 output signal light is mixed with the input signal light and output to the output highway, resulting in a deterioration of the SN ratio on the receiving side.

As a means to solve this problem, the wavelength of the signal light is shifted between the input eight ways and the output highway, and the multiplexer 1
4, it may be possible to send only the output signal lights from the wavelength conversion elements W□ to W to the output highway, but it is not preferable that the signal lights on the input and output highways have different wavelengths.

The present invention aims to solve such problems,
While ensuring that the wavelengths of the signal lights on the input and output highways do not differ, the input signal light is not mixed with the output signal light that is converted by the wavelength conversion switch and output to the output highway, and the S/N ratio on the receiving side is improved. It is an object of the present invention to provide a wavelength division type optical communication path device that can prevent deterioration.

[Means to solve the problem] FIG. 1 is a block diagram of the principle of the present invention.

In FIG. 1, 1 is a wavelength division type optical channel device,
This wavelength division type optical channel device 1 accommodates an input/output highway 11.12 to be described later, and performs wavelength conversion into a plurality of optical signals of wavelength multiplexed wavelengths (for example, λ□, λ2, ... λ.). Switching is performed by changing the order of input wavelength multiplexing.

11.12 are an input highway and an output highway, and for example, wavelengths λ1 . λ2. ... A plurality of optical signals of λn are wavelength-multiplexed and propagate.

13 is a demultiplexer (wavelength separator), and this demultiplexer 13
are wavelength-multiplexed wavelengths λ1. λ2. ... demultiplexes each optical signal of λn.

14 is a multiplexer (wavelength multiplexer), and this multiplexer 14
is the demultiplexed wavelength λ1. Each optical signal of λj, . . . λ is multiplexed.

15a is a first wavelength conversion switch, and this first wavelength conversion switch 15a converts each wavelength λ1 . λ2. ..., λ. , wavelengths λ1λ2, ... λ, which are different from any of these, respectively. ' and outputs the wavelength λ1. λ2. ..., removes crosstalk of input signal light of λn.

15b is a second wavelength conversion switch, and this second wavelength conversion switch 15b is different from the first wavelength conversion switch 1.
Each wavelength λ1 λ2 of the signal light output from 5a,
...λ. ' are the wavelengths λ1 . . . of the input highway signal light, respectively. λ2. ...λ. The wavelengths λi, λj, . . . , .

In addition, 1+ Jt..., X is 1, 2. ...n, and the wavelengths λi, λJ, . λ2. . . . One is selected from among λn without duplication.

Furthermore, among the above-described configurations, the second wavelength conversion switch 15
1 multiplexer 14 by omitting the function of removing crosstalk in b.
It may also be configured to remove crosstalk when outputting from.

Furthermore, the first wavelength conversion switch 15a may include up to the demultiplexer 13, and the second wavelength conversion switch 15b may include up to the multiplexer 14.

[Function] Multiplexed wavelength λ1 sent from input highway 11
．． λ2. ...λ. After being demultiplexed by the demultiplexer 13, the optical signals of each wavelength λ1 . λ2. ...λ. But each of these wavelengths λ
1. λ2. ... Both wavelengths λ1 are different from λn.
, λ2 ... λn', and the first
from the wavelength conversion switch 15a to the second wavelength conversion switch 15b.

At this time, the output signal lights of the converted wavelengths λ, λ2, . λ2゜... λn input signal light (see dotted line arrow in Figure 1) is mixed in, resulting in so-called crosstalk, but the wavelengths λ, λ2
..., λn' are the respective wavelengths λ□, λ2 . ..., λn, so the wavelength λ1 . λ2. ..., λn
The crosstalk of the input signal light can be removed, and the wavelengths λ, , λ after conversion can be removed by the second wavelength conversion switch 15b.
2..., only the output signal light of λn' can be input.

In the second wavelength conversion switch 15b, the wavelength λ,
, λ2 ... λn' are the wavelengths λl and λ, respectively
j, . . . are converted into λX and sent to the single multiplexer 14.

At this time as well, the converted wavelength λ1. λj,... λX output signal light has wavelengths λ□, λ2..., λn before conversion
' input signal light (see dotted line arrow in FIG. 1) is mixed in, but the wavelengths λ, , λ2 , .
λj,..., λX (that is, λ1.λ2... λ
n), so the wavelengths λ, , λ, ・
..., the crosstalk of the input signal light of λn' can be removed, and the wavelengths λi, λj, . . . after being converted into one multiplexer 14
- Only λX output signal light can be input.

As a result, the multiplexed wavelengths λ1 . λ2. ..., λn each have a wavelength λ1 . It is converted into optical signals of λj, ..., λX,
Wavelength λ□, λ2. .

Note that, after conversion by the second wavelength conversion switch 15b, input signal lights of wavelengths λ, , λ2 . . .
Instead of being removed at the time of output from the multiplexer 14, as shown by the chain line in FIG. 2, it may be removed at the time of output from the multiplexer 14.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

First, the first embodiment will be described. FIG. 2 is a block diagram showing the first embodiment of the present invention.

In FIG. 2, 2 is a wavelength division type optical channel device,
This wavelength division type optical channel device 2 accommodates input/output highways 11 and 12, which will be described later. In this case, switching is performed by performing wavelength conversion on a plurality of optical signals of λ1, λ2, λ3, λ4) and changing the input wavelength multiplexing order.

11.12 are an input highway and an output highway, and these input highway 11 and output highway 12
A plurality of optical signals with wavelengths λ1 to λ travel on the top in a wavelength-multiplexed state.

13 is a demultiplexer (wavelength demultiplexer: WDMUX), and this demultiplexer 13 demultiplexes each wavelength-multiplexed optical signal of wavelength λ, to λ.

14 is a multiplexer (wavelength multiplexer: WMUX), and this multiplexer 14 separates wavelengths λ1. λj, λk.

Each optical signal considering λ is multiplexed and output, but at the time of output,
λ1. The optical signal of λ and the crosstalk light (here, the optical signal of wavelength λ, ~λ8) are distributed to λj, λ, the crosstalk light of wavelength λ5 to λ is removed, and the crosstalk light of wavelength λl,
Only the optical signals of λl are multiplexed onto λj and λ and output.

Reference numeral 16 denotes a wavelength conversion switch, which includes a first wavelength conversion switch 16a and a second wavelength conversion switch 16b.

16a is a first wavelength conversion switch, which includes a wavelength conversion element Wz, t Wxz t W13 * WL4 and a multiplexer M
, and the optical signals of wavelengths λ1 to λ, which are demultiplexed and sent by the demultiplexer 13, are converted to wavelength conversion elements wt1t, w12t, W13, and wx+, respectively (that is, λ1 to λ4). Wavelength λ5 of another wavelength. λ6. λ7
．． λ.

These optical signals with wavelengths λ, .about.λ are multiplexed by a multiplexer M0 and output. Note that this multiplexer M1 has wavelengths λ, ~λ, at the time of its output.
optical signal and crosstalk light (here, wavelengths λ1 to λ,
input optical signals) and remove crosstalk light with wavelengths λ□ to λ, and then remove crosstalk light with wavelengths λ5 to λ. It is designed to multiplex and output only the optical signals.

16b is a second wavelength conversion switch, which includes a demultiplexer D□ and wavelength conversion elements w, t w22. w2. , w24, and the wavelengths λ5 to λ are multiplexed and sent out from the first wavelength conversion switch 16a. Demultiplexer D
After demultiplexing, the wavelength λ, ~λ. The optical signals of the wavelength conversion elements wzt t W22 e w2. tW2.
So, the wavelength λ1. It is designed to convert into optical signals of λj, λ, and λt and output them.

Note that the wavelength conversion elements W1□ to WL4. Semiconductor lasers are used as W21 to W24.

Moreover, +Q in lv j+ is any one of 1 to 4, and the wavelength λ1. λj, λ, and λe are each selected from among the wavelengths λ1 to λ of the input signal light without overlapping.

With the above configuration, the multiplexed optical signals of wavelengths λ, ~λ, sent from the input highway 11 are demultiplexed by the demultiplexer 13, and then subjected to each wavelength conversion by the first wavelength conversion switch 16a. Element W, 0. Proceed to W, , W13°W14, and set each wavelength λ□, λ2 . λ1. λ4 is each of these wavelengths λ□~λ
, both have different wavelengths λ,.

λ6. λ7. λ, respectively, and sent to the multiplexer M.

At this time, wavelength conversion elements W8□, W1□f W13t w
14, each having a wavelength λ9. λ6. λ7
In addition to the optical signal of ゜λ3, the wavelength λ1. λ2. λ,.

Crosstalk occurs in which the input signal light of λ4 (see the dotted arrow in FIG. 2) is mixed. Therefore, the wavelength λ5. λ6. λ7. The wavelength λ1.λ before being converted into an optical signal of λ1. λ2. λ1. λ is mixed in.

However, when the multiplexer M1 outputs wavelengths λ1 to λ,
Since the crosstalk light of wavelengths λ5 to λ is removed from the multiplexer M8, Only the optical signals are multiplexed and output.

The optical signals of wavelengths λ, ~λ, multiplexed in this way are sent from the multiplexer M□ of the first wavelength conversion switch 16a to the demultiplexer of the second wavelength conversion switch 16b.

sent to.

Then, the demultiplexer D□ demultiplexes the wavelengths λ5 to λ, and then the wavelength conversion elements w, 1. W2z, w,,.

The optical signals of wavelengths λ, . λJ.

λ and into one optical signal, respectively, and send it to the multiplexer 14.
Output to.

Also at this time, the wavelength conversion elements W2□, W2□, W2□.

The output signals from Wz4 have wavelengths λi and λj, respectively.

In addition to the optical signal of λp, the wavelength λ5. λ6゜λ
7. λ. A crosstalk occurs in which the input signal light of λ (see the dotted arrow in FIG.
1. λj, λ, the wavelength λ9 . λ
6. λ7. λ8 will be mixed in.

However, since the multiplexer 14 removes the crosstalk light of wavelengths λ5 to λ at the time of output, only the optical signal of λl is multiplexed from the multiplexer 14 to wavelengths λi, λj, and λ. converted and output.

In this way, the optical signals with wavelengths λ, ~λ, are subjected to desired frequency conversion to have wavelengths λi, λj, λ, and λ2, and the optical signals are multiplexed and output without crosstalk light being mixed in. Sent out onto Highway 12.

As a result, on input highway 11 and on output highway 12
While using signal light with the same wavelength as above, the input signal light is prevented from being mixed into the output signal light that is converted by the wavelength conversion switch 16 and output to the output highway 12, and the S/N ratio on the receiving side is reduced. It has the effect of preventing therefore,
By connecting these wavelength division type optical communication path devices in multiple stages, it becomes possible to construct a large-scale wavelength division type optical communication path.

Note that assuming that the first wavelength conversion switch 16a includes the demultiplexer 13, the demultiplexer 13 and the wavelength conversion element w11.
It may also be defined as consisting of W1□, W□, , W14 and the multiplexer M1, and the second wavelength conversion switch 16b
Assuming that up to the multiplexer 14 is included, the demultiplexer D, the wavelength conversion element w, 1. W22. lol.

It may be defined to consist of the 3TW 24 and the multiplexer 14.

Next, to explain the second embodiment, FIG. 3 is a block diagram showing the second embodiment of the present invention, and the same parts as in the first embodiment are given the same reference numerals. The explanation will be omitted.

In FIG. 3, 3 is a wavelength division type optical channel device,
This wavelength division type optical communication path device 3 also has the same features as in the first embodiment.
It accommodates input/output highways 11 and 12, and is equipped with a demultiplexer 13, a wavelength conversion switch 17, and a multiplexer 14, and is equipped with a demultiplexer 13, a wavelength conversion switch 17, and a multiplexer 14. Switching is performed by performing wavelength conversion on a plurality of optical signals of λ2°λ, λ, and changing the input wavelength multiplexing order.

14 is a multiplexer (wavelength multiplexer: WMUX).

This multiplexer 14 receives the demultiplexed wavelengths λ1. λj, λk.

Although each optical signal of λl is multiplexed and output, the multiplexer 14 in this example does not need a function to remove crosstalk light.

Reference numeral 17 denotes a wavelength conversion switch, which includes a first wavelength conversion switch 17a and a second wavelength conversion switch 17b.

17a is a first wavelength conversion switch, which includes wavelength conversion elements W□, W, , W13. W Yu, and duplexer D41
゜Equipped with Dl, , Dl, , D, 4, 1 demultiplexer 1
Each of the optical signals having wavelengths λ1 to λ demultiplexed by the wavelength converting element W11. W1□f w,, t w, , these wavelengths λ, ~λ, and another wavelength λ5. λ. ,λ
7. λ.

are converted into each optical signal, and each demultiplexer D11゜D,
2. D.3. It is designed to be sent to D.

Each demultiplexer...D□2. D□3. At the time of output, the optical signals with wavelengths λ and ~λ and the crosstalk light (input optical signals with wavelengths λ1 ~ λ) are distributed, respectively.
Crosstalk light with wavelengths λ1 to λ is removed, and wavelengths λ,
It is designed to output only an optical signal of ~λ.

17b is a second wavelength conversion switch, and wavelength conversion elements w,,,w! ,, w2. , w14 and duplexer D2□
.

D, , D, , D, , each branching filter D□tt of the first wavelength conversion switch 17a
D1! The optical signals of wavelengths λ, to λ8 sent from tD14 are transmitted to each wavelength conversion element W, 1. W, Wi3. W
24, respectively with wavelengths λ1. λj, λ, and λl are converted into optical signals and sent to the respective demultiplexers D21. D, □f D
,,, It is designed to be sent to Dl4. Each of these branching filters D21°Dl2. Dl3. Dl4 also has wavelengths λ1 . The optical signal of one party and the crosstalk light with wavelengths λ5 to λ8 are distributed to λJ, λ, the crosstalk light with wavelengths λ, to λ9 is removed, and the wavelengths λi,
λj, λk.

It is designed to output only λ-critical optical signals.

With the above-described configuration, the multiplexed optical signals of wavelengths λ1 to λ sent from the input highway 11 are demultiplexed by the demultiplexer 13, and then each of the wavelength conversion elements W of the first wavelength conversion switch 17a is demultiplexed by the demultiplexer 13. □1. W1□, W□,.

Wi, and each wavelength λ1. λ2. λ3. λ4 is a wavelength λ9 . . . which is different from each of these wavelengths λ, ~λ. λ6゜λ7. λ, and further, each demultiplexer D11
．． D, , D, , D, , each wavelength conversion element W.

Wavelengths λ1 to λ generated when outputting W1□, W, , W, ,
.

After removing the crosstalk light, each converted wavelength λ,
~λ, only the optical signal is sent to the second wavelength conversion switch 17b.

Then, each of the following wavelength conversion elements W, 1. W2□, W23
In ゜W24, each wavelength λ5 to λ is the wavelength λ of the input signal light.

~λ, one of the wavelengths λ1. are converted into optical signals of λj, λ, and λl, respectively, and further, each demultiplexer D2□, Dl2 . Dl3゜D
l4, each wavelength conversion element W2□, W, , W23.
W.

The crosstalk light of wavelengths λ, ~λ, which occurs when outputting is removed, and the converted wavelengths λ, λj, λk are obtained.

Only the output optical signal of λl is sent to the multiplexer 14.

In the multiplexer 14, each wavelength λ1. The output optical signal of λl is multiplexed onto λJ and λ and sent to the output highway 12.

In this way, desired frequency conversion is performed on the optical signals of wavelengths λ, to λ, and wavelengths λ1. The optical signals with λj and λ as one party are multiplexed without being mixed with crosstalk light and sent to the output highway 12. In this second embodiment, as in the first embodiment, the input While using signal lights of similar wavelengths on highway 11 and output highway 12,
Mixing of the input signal light into the output signal light is prevented, which has the effect of preventing deterioration of the SN ratio on the receiving side, and it becomes possible to construct a large-scale wavelength division type optical communication path.

Note that the duplexer D2□9D2□ in this second embodiment.

Dl3. In place of Dl4 and the multiplexer 14, a multiplexer 14 capable of removing losstalk light may be provided as in the first embodiment. In other words, the optical signal is input highway 1
1→Demultiplexer 13→Wavelength conversion element W1□, W 1 t W
l! t w14→14→D1. , D12. D,
.

D14→Wavelength conversion element W21. W22. Wi3. W24
It may be configured such that the processing is performed in the order of → multiplexer 14 → output highway 12.

Further, assuming that the first wavelength conversion switch 17a includes the demultiplexer 13, the demultiplexer 13 and the wavelength conversion element W,
w, 2. W□3. W engineering, and duplexer D engineering 1. D1□, Dyo1. It may also be defined as consisting of D, and the second
Assuming that the wavelength conversion switch 17b of up to the multiplexer 14 is included, wavelength conversion elements W2□, W2□, W2. , W
, 4 and a duplexer D21. D,,D23. D24 and multiplexer 1
It may be defined to consist of 4.

[Effects of the Invention] As described in detail above, according to the wavelength division type optical communication path device of the present invention, while signal light having the same wavelength is used on the input highway and the output highway, it is possible to This has the advantage that it is possible to prevent input signal light from being mixed in, thereby preventing deterioration of the S/N ratio on the receiving side, and it is possible to construct a large-scale wavelength division type optical communication path.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram showing a first embodiment of the invention, Fig. 3 is a block diagram showing a second embodiment of the invention, and Fig. 4 is a block diagram of a conventional example. FIG. In the figure, 1.2.3 is a wavelength division type optical channel device, 11 is an input highway, 12 is an output highway, and 13, Dl, Dl, to D14 are demultiplexers (wavelength separators). 14, M□ is a multiplexer (wavelength multiplexer), 16.17 is a wavelength conversion switch, 15 a, 16 a, l 7 a is the first wavelength conversion switch, 15b, 16b, 17b is the second wavelength conversion Switch, W□□~W□,, W2. ~wz4 is a wavelength conversion element.

Claims (1)

[Scope of Claims] A wavelength division type optical channel device (1) that accommodates wavelength-multiplexed input/output highways (11, 12) and performs switching by performing wavelength conversion and changing the input wavelength multiplexing order, a first wavelength conversion switch (15a) that converts each wavelength (λ_1 to λ_n) of input highway signal light to a different wavelength (λ_1' to λ_n') and outputs the same; and the first wavelength conversion switch. The output signal light from (15a) is the wavelength (λ_i to λ_x) of the input highway signal light.
A wavelength division type optical communication path device, characterized in that a second wavelength conversion switch (15b) is provided for outputting the signal back to the output highway (12).