JP2001352309A - Wavelength division multiplex system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength division multiplex system (WDM) where a transmission section can accurately and surely obtain a restored signal even on the occurrence of a connection error in a cable installed between a reception section and the transmission section in the WDM system and on the occurrence of a channel setting error in the transmission section and the reception section. SOLUTION: In the transmission section, after a 1:n division section 103 divides each frame of received signals into n-sets of signals, number addition sections 104 (1-n) add specific numbers denoting the division sequence to the frames, and an n:1 restoration section 111 of the reception section restores the divided signals to the original signals by integrating the divided signals on basis of the division sequence.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a WDM (Wavelength Division) capable of realizing large capacity and long distance communication.
Multiplex) system.

[0002]

2. Description of the Related Art The recent technology has made remarkable progress, and the ratio of stoppage of services and failure of machines due to human error has been increasing. W that can realize large capacity and long distance communication
In the DM system, the number of cables to be laid is increased in accordance with the increase in the capacity of the multiplexed signal, and the line is set such that the number of channels accommodated in the transceiver is increased.

Therefore, constructing such a WDM system requires a great deal of man-hours and increases the possibility of human error such as a cable connection error or a transmission / reception unit line setting error. Since the WDM system is capable of large-capacity communication, the effect on communication services when such a failure occurs is immense.

[0004] A conventional WDM system will be described with reference to FIG. FIG. 4 is a system configuration diagram showing an example of a conventional WDM system. As shown in FIG. 4, the transmission unit divides the transmission signal into n transmission signals and transmits the divided transmission signals. It is essential for the reception unit to reliably restore the n transmission signals.

According to FIG. 4, an SDH / SONET signal received by a transmitter of a WDM system is converted into an optical / electrical
1 (1 to n) to convert the signal into an electric signal,
A1 indicates the beginning of the frame from the electric signal,
Frame synchronization is established using the A2 byte.

[0006] The frame structure of an SDH (Synchronous Digital Hierachy) signal has a payload portion for transmitting main information and a SOD (Section Over Hetero) for transmitting transmission path management information.
ad), and the SOH is also divided into bytes so that various management information can be transmitted. Here, A1 byte and A2 byte are the SOH
Is used to establish synchronization with the names of the parts separated in the.

Next, the 1: n dividing section 403 divides the signal into n in a time-division manner in the order of input from the synchronous circuit section 402 and sequentially outputs the divided signals to the subsequent electrical / optical converting sections 401 (1-n). . The electrical / optical converters 404 (1 to n) convert the input electrical signals into optical signals and transmit the optical signals to the WDM coupler 405. The WDM coupler 405 is connected to each electrical / optical converter 404.
Each of the optical signals received from (1 to n) has a predetermined wavelength (λ1
To λn) and transmit it to the optical fiber transmission line.

[0008] The WDM coupler 406 receives optical signals of wavelengths λ1 to λn from the optical fiber transmission line, and transmits the signals to the optical / electrical conversion units 407 (1 to n) of the receiving unit for each wavelength. Each of the optical / electrical conversion units 407 (1 to n) converts the received optical signal into an electric signal and outputs the electric signal to the subsequent synchronization circuit unit 408 (1 to n). The synchronization circuit unit 408 (1 to n) establishes frame synchronization using A1 and A2 bytes indicating the head of the frame from the input electric signal. The storage unit 409 temporarily stores the signals output from the synchronization circuit units 408 (1 to n), and the n: 1 restoration unit 410 integrates the signals read from the storage unit 409 and restores the original signal. I do.

The electrical / optical conversion unit 411 includes an n: 1 restoration unit 4
In step 10, the restored electric signal is converted into an optical signal, and an SDH / SONET signal is output as a transmission signal of the receiving unit. As described above, conventionally, the signal divided by the transmission unit is received by the reception unit via the optical fiber transmission line, and the reception unit restores the original signal by integrating the divided signals.

However, in the prior art, the dividing operation on the transmitting side and the restoring operation on the receiving side are both fixed operations. Therefore, for example, when a cable error or the like occurs, the order of division at the transmission unit and the order of restoration at the reception unit change, and it becomes impossible for the reception unit to restore the signal as received by the transmission unit. Was included.

As in the case where the above-described cable error occurs, the electric / optical converters 404 and 411, the optical / electric converters 401 and 407, the synchronous circuit units 402 and 408, W
The wavelength transmitting unit in the DM coupler 405, the WDM coupler 406
Of the wavelength receiving unit in the unit, the transmitting unit and the WDM coupler 405
If a failure occurs in any one of the cables, such as a cable connecting the receiver and a cable connecting the receiver to the WDM coupler 406, the receiver cannot restore the original signal.

Next, the operation of the conventional example will be specifically described with reference to FIG. According to FIG. 5, the transmission unit is 10 Gb
/ S optical signal (the same figure: ABCD) is received. Optical signal A
The BCD is converted into an electric signal via an optical / electrical conversion unit 501, and A1 and A2 bytes indicating the head of the frame are searched out from the signal by the synchronization circuit unit 502, and frame synchronization is established.

Thereafter, in the 1: 4 division unit 503, the output signal from the synchronization circuit unit 502 is divided into four frames A, B,
The frame A is divided into C and D,
The frame B is converted into an optical signal in the electrical / optical converter 504 (2), the frame C is converted into an optical signal in the electrical / optical converter 504 (3), and the frame D is converted into the optical signal in (1). Is converted into an optical signal by the electrical / optical converter 504 (4).

Each of the output signals (A, B, C, D) from the electrical / optical converter 504 (1-4) is a WDM coupler 505.
Is converted into a predetermined signal. Electric / optical converter 504
The output signal of (1) is converted into a signal of wavelength λ1,
The output signal of the optical converter 504 (2) is converted into a signal of wavelength λ2, the output signal of the electrical / optical converter 504 (3) is converted into a signal of wavelength λ3, and the output signal of the electrical / optical converter 504 (4) is converted. The output signal is converted into a signal of wavelength λ4. Thus W
After converting the signal wavelength, the DM coupler 505 transmits the optical signals A, B, C, and D to the optical fiber transmission line.

The WDM coupler 506 receives the signals (A to D) of the wavelengths λ1 to λ4 transmitted from the transmission unit, and converts the signals from optical signals to electric signals by the optical / electrical conversion units 507 (1 to 4). The received signal A having the wavelength λ1 is converted by the optical / electrical conversion unit 507.
The received signal B having the wavelength λ2 is converted into the electric signal A in (1).
Is converted into an electric signal B by the optical / electrical conversion unit 507 (2), and the received signal C of the wavelength λ3 is
The received signal D having the wavelength λ4 is converted into an electric signal C in (3).
Is converted into an electric signal D by an optical / electrical converter 507 (4).

Here, consider a case where an error occurs in the connection of the cable between the WDM coupler 506 and the receiving unit. For example,
The signal A of wavelength λ1 and the signal D of wavelength λ4 transmitted from the WDM coupler 506
7 (1) and the optical / electrical conversion unit 507 (4) normally receive the signal B of the wavelength λ2.
The signal C having the wavelength λ3 received at (3) is received by the optical / electrical converter 507 (4).

The optical / electrical conversion units 507 (1 to 4) convert the received optical signals A to D of λ1 to λ4 into electric signals, and the synchronization circuit 508 (1 to 4) converts A1 to A1 of each of the frames A to D. , A
Two bytes are located and frame synchronization is established. Here, the transmission section is divided by dividing the 10 Gb / s signal in the receiving section, so that a transmission delay difference occurs between the signals A to D. The difference is absorbed by temporarily storing the output signal in the storage unit 509.

[0018]

However, 4: 1.
The restoring unit 501 reads out and restores the signals A to D from the storage unit 509. The restoring unit 501 synchronizes the synchronization circuit unit 508 (1), the synchronization circuit unit 508 (2), the synchronization circuit unit 508 (3), and the synchronization circuit unit 508 ( To integrate and restore the output in the order of 4), WD
If the cable connection between the M coupler 506 and the receiving unit is incorrect, the connection is erroneously restored to ACBD. As described above, the signal (ACBD) transmitted from the receiving unit is different from the signal (ABCD) received by the transmitting unit, and when a failure occurs, the signal cannot be accurately restored.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and there is a case where a connection error occurs in a cable between a WDM coupler and a transmission / reception unit, or a line setting error occurs in a transmission unit and a reception unit. It is another object of the present invention to provide a WDM system capable of accurately and surely restoring an original signal in a transmitting unit.

It is another object of the present invention to provide a WDM system that compensates for the quality at the time of restoration in the forward section even when a failure occurs in the transmission section and the quality of the transmission signal deteriorates.

[0021]

In order to achieve the above object, the invention according to claim 1 divides a received signal from the outside into n (n is an arbitrary natural number) signals in the order received,
A transmitting device that adds and transmits pertinent order information for each of the divided signals, and a receiving device that receives n signals and integrates and restores n signals based on the order information It is characterized by.

According to a second aspect of the present invention, in the first aspect of the present invention, the transmitting device divides the received signal from the outside into n signals in the order in which the signal is received; Correspondingly, one of n signals is input, and n number adding means for adding order information to the input signal is provided.

The invention according to claim 3 is the invention according to claim 1 or 2
In the described invention, the WDM system includes a first WDM coupler that converts each of n signals received from the transmission device into a predetermined wavelength and transmits the converted signal.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the WDM system receives n signals from the first WDM coupler and receives the n signals for each predetermined wavelength. It has a second WDM coupler for transmitting to the device.

According to a fifth aspect of the present invention, an externally received signal is divided into n (n is an arbitrary natural number) signals in the order of reception, and pertinent sequence information is added to each of the divided signals.
A transmitting device that splits each of the n signals to which the order information is added into m (m is an arbitrary natural number) and transmits them, receives n × m signals, and sets m for each of the n signals And a receiving device that selects one of the signals of the book, and integrates and restores the selected n signals based on the order information.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the transmitting device divides the received signal from the outside into n signals in the order in which the signal is received; Correspondingly, one of the n signals is input, and n number adding means for adding order information to the input signal, and n number of signals, the order of which is added by the number adding means, N branching means for branching each signal into m signals, and one of the n × m signals output from the branching means are input, the input signal is converted into an optical signal and transmitted. ,
and n × m first conversion means.

According to a seventh aspect of the present invention, in the fifth or sixth aspect of the present invention, the receiving device is configured to convert nxm second signals into electrical signals by converting nxm signals into electrical signals; The second
A selecting means for inputting the signals converted by the converting means and selecting one signal from the m signals for each of the n signals, and sequentially selecting the n signals selected by the selecting means And restoring means for integrating and restoring based on.

According to an eighth aspect of the present invention, in the invention according to any one of the fifth to seventh aspects, the WDM system converts each of the n × m signals received from the transmitting device into a predetermined wavelength and transmits the converted signal. And a first WDM coupler.

According to a ninth aspect of the present invention, in the eighth aspect of the present invention, the WDM system receives nxm signals from the first WDM coupler and divides the signals by n for each predetermined wavelength.
It has a second WDM coupler for transmitting × m signals to the receiving device.

[0030]

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

FIG. 1 is a system configuration diagram showing an embodiment of a WDM system according to the present invention. In the transmission unit of the WDM system, the SDH / SONET signal is received by the optical / electrical conversion unit 101 and converted from an optical signal to an electric signal.
The synchronization circuit unit 102 establishes frame synchronization using A1 and A2 bytes indicating the head of the frame of the output signal from the optical / electrical conversion unit 101, and the 1: n division unit 103
It is divided into n outputs in a time-division order in the order of input from the synchronization circuit unit 102. The time-divided signal is assigned to the number adding unit 1
The numbers are input in the order from 04 (1) to the number adding unit 104 (n).

Thereafter, each number adding section 104 (1 to n)
, Adds a unique number to the overhead of the frame divided and input by the 1: n division unit 103 so that the order of division by the 1: n division unit 103 is determined, and outputs the result. The output signals of the number adding units 104 (1 to n) are converted from electric signals to optical signals by the corresponding electric / optical conversion units 105 (1 to n), and transmitted to the WDM coupler 106. The WDM coupler 106 is connected to the electrical / optical converter 105 (1
To n) are converted into wavelengths λ1 to λn, respectively, and transmitted to an optical fiber transmission line.

The WDM coupler 107 receives n optical signals from the optical fiber transmission line and transmits them to the optical / electrical conversion units 108 (1 to n) corresponding to each of the wavelengths λ1 to λn. The optical / electrical conversion units 108 (1 to n) convert the received optical signals into electric signals and output the electric signals to the subsequent synchronization circuit units 109 (1 to n). The synchronization circuit units 109 (1 to n) find the A1 and A2 bytes indicating the beginning of the frame and establish frame synchronization.

The n signals output from the synchronization circuit units 109 (1 to n) are temporarily stored in the storage unit 110 to absorb a difference in transmission delay between frames caused by division in the transmission unit. The n: 1 restoring unit 111 reads out the signal from the storage unit 110, refers to the unique number added by the transmitting unit, and integrates and restores the signal in the order of division by the transmitting unit. Then, the signal output from the n: 1 restoration unit 111 is converted from an electric signal to an optical signal by the electric / optical conversion unit 112, and is output again as an SDH / SONET signal.

As described above, according to the present invention, after the transmission unit divides each frame into n signals, a unique number indicating the order of division is added to the frame. Each frame is integrated and restored. Therefore,
According to the present invention, when a connection error occurs in the cable between the WDM coupler 106 and the transmission unit, or in the cable between the WDM coupler 107 and the reception unit, or a line setting error occurs in the transmission unit and the reception unit. Even in the case of the transmitting part,
And it is possible to reliably restore the original signal.

Next, an embodiment of the present invention will be specifically described with reference to FIG. In the embodiment shown in FIG. 2, the transmitting unit is an optical / electrical converting unit 201, a synchronous circuit unit 2
02, 1: 4 dividing section 203, number adding section 204 (1-
4), an electrical / optical converter 205 (1-4), and a receiver as an optical / electrical converter 208 (1-4), a synchronous circuit unit 209 (1-4), a storage unit 210, 4: 1 restoration unit 21
1. It is composed of an electrical / optical converter 212.

In the embodiment shown in this figure, the transmitting unit receives an optical signal having a transmission rate of 10 Gb / s, divides the received signal into four signals (2.5 b / s), and multiplexes the signals by the WDM method. Transmitting to fiber transmission line. In particular, in the present embodiment, it is assumed that an error has occurred in the cable connection between the WDM coupler 207 and the receiving unit.

10G received by the transmitter of the WDM system
The optical signal of b / s is converted into an electrical signal by the optical / electrical conversion unit 201, and the synchronization circuit unit 202 searches for A1 and A2 bytes indicating the head of the frame of the electrical signal, and establishes frame synchronization. After the frame synchronization is established in the synchronization circuit unit 202, the signal (ABCD) output from the synchronization circuit unit 202 is divided by the 1: 4 division unit 203 into the synchronization circuit unit 20.
4 frames A to D in a time-division order in the order entered from 2
(2.5 Gb / s). Divided signal A,
B, C, and D are numbered units 204 (1 to 4) in that order.
Is input to

The number adding units 204 (1 to 4) determine the order of the frames A to
$ 1, $ 2, $ 3, and $ 4 are added to the overhead of D, respectively, and output to the subsequent electrical / optical conversion units 205 (1 to 4). The electrical / optical converters 205 (1 to 4) convert the input signals A to D into optical signals and transmit the optical signals to the WDM coupler 206. The WDM coupler 206 converts the received signals A to D into predetermined wavelengths λ1 to λ4, respectively.

The signal A transmitted from the electrical / optical converter 205 (1) is converted by the WDM 206 into a signal A having a wavelength λ1, and the signal B transmitted from the electrical / optical converter 205 (2).
Is converted into a signal B of wavelength λ2 by the WDM coupler 206, and the signal C transmitted from the electrical / optical converter 205 (3)
Is converted into a signal C of the wavelength λ3 by the WDM coupler 206, and the signal D transmitted from the electrical / optical converter 205 (4).
Is converted by the WDM coupler 206 into a signal D having a wavelength λ4. After that, the signals A to D whose wavelengths have been converted by the WDM coupler 206 are transmitted to the optical cable transmission line.

The WDM coupler 207 receives the four optical signals A to D from the optical cable transmission line, and
08 (1-4). Here, in the present embodiment,
Since the cable connection between the WDM coupler 207 and the receiving unit is incorrect, the signal B of the wavelength λ2
The signal C having the wavelength λ3 transmitted to (3) is transmitted to the optical / electrical conversion unit 208 (2). As for the other signals A and D, the signal A of the wavelength λ1 is converted to the optical / electrical converter 208 (1)
Is transmitted to the optical / electrical conversion unit 208.
Sent to (4).

The optical / electrical converters 208 (1 to 4) convert the received optical signals A to D into electric signals and output them to the corresponding synchronous circuit units 209 (1 to 4) at the subsequent stage. Synchronous circuit section 2
09 (1 to 4) are A1, A indicating the head of the frame.
Frame synchronization is established using two bytes. The transmission delay difference between the signals A, B, C, and D caused by the transmission path dispersion of the transmission unit is absorbed by temporarily storing the four signals in the next storage unit 210.

Thereafter, the 4: 1 restoring unit 211 sequentially reads signals from the storage unit 210 based on the unique numbers # 1, # 2, # 3, and # 4 added by the transmission unit (A, B, C,
D) By integrating (ABCD), the original signal is restored. The electrical / optical converter 212 converts the signal ABCD input from the 4: 1 restoration unit 211 into an optical signal ABCD,
A signal of 0 Gb / s is output.

Next, another embodiment of the present invention will be described in detail with reference to FIG. According to FIG. 3, the WDM system according to the present embodiment includes an optical / electrical
1, synchronization circuit section 302, 1: 4 division section 303, number adding section 304 (1-4), branching section 314 (1-4),
An optical / electrical conversion unit 308 (1 to 8) and a synchronous circuit unit 309 (1 to 8) are provided in the receiving unit.
8), selection unit 310, storage unit 311, 4: 1 restoration unit 31
2. It has an electrical / optical converter 313.

In the present embodiment, the optical signal ABCD of 10 Gb / s is converted into four signals A, B, C, D (2.5 G
b / s), and when transmitting to the optical fiber transmission line by the WDM method, the electrical / optical converter 305 (2)
Let's consider the case where a failure occurs.

10 received by the transmitting unit of the WDM system
The optical signal ABCD of Gb / s is converted into an electric signal by the optical / electrical conversion unit 301. The synchronization circuit unit 302 outputs a signal A,
A1, A indicating the beginning of the frame for B, C, D
Locate 2 bytes and establish frame synchronization. 1: 4
The division unit 303 performs time-divisional division of the four signals A, B, C, and D (2.5 Gb /
s) and outputs the result to the number adding unit 304 (1 to 4). At this time, signal A is output to number adding section 304 (1), signal B is output to number adding section 304 (2), signal C is output to number adding section 304 (3), and signal D is number added. Output to the unit 304 (4).

Thereafter, the number adding units 304 (1 to 4)
As shown in the order of division by the 1: 4 division unit 303,
The unique number $ 1,
Add $ 2, $ 3, and $ 4. At this time, the unique number # 1 is added to the signal A, the unique number # 2 is added to the signal B, the unique number $ 3 is added to the signal C, and the unique number $ 4 is added to the signal D. You.

Next, after the unique numbers are added by the number adding sections 304 (1 to 4), the outputs from the number adding sections 304 (1 to 4) are input to the branching sections 314 (1 to 4), respectively. . The signal A output from the number adding section 304 (1) is input to the electric / optical conversion section 305 (1) and the electric / optical conversion section 305 (5) through the branching section 314 (1). The signal B output from 2) is output to the branching unit 314
The signal is input to the electric / optical conversion unit 305 (2) and the electric / optical conversion unit 305 (6) through (2), and the number adding unit 304
The signal C output from (3) is input to the electrical / optical converter 305 (3) and the electrical / optical converter 305 (7) through the branching unit 314 (3), and is output from the number adding unit 304 (4). The divided signal D is passed through the branching unit 314 (4) to the electrical / optical converter 305 (4) and the electrical / optical converter 305.
Input to (8).

The signals A, B, C, and D output from the electrical / optical converters 305 (1 to 8) are transmitted to the WDM coupler 306, converted into respective predetermined wavelengths, and transmitted to the optical fiber transmission line. Is done. The signal A output from the electrical / optical converter 305 (1) is converted into a wavelength λ1 by the WDM coupler 306, and the signal B output from the electrical / optical converter 305 (2).
Is converted to a wavelength λ2 by the WDM coupler 306, and the signal C output from the electrical / optical converter 305 (3) is converted to a wavelength λ3 by the WDM coupler 306, and
The signal D output from (4) is converted to a wavelength λ4 by the WDM coupler 306, and the signal A output from the electrical / optical converter 305 (5) is converted to a wavelength λ5 by the WDM coupler 306, and the electrical / optical conversion is performed. The signal B output from the unit 305 (6) is converted to a wavelength λ6 by the WDM coupler 306,
The signal C output from the optical conversion unit 305 (7) is converted into a wavelength λ7 by the WDM coupler 306, and
The signal D output from 5 (8) is converted by the WDM coupler 306 into a wavelength λ8. Thereafter, the wavelength-converted signal is transmitted from the WDM coupler 306 to the optical fiber transmission line.

The WDM coupler 307 receives eight optical signals from the optical fiber transmission line, and converts the eight optical signals into an optical / electrical converter 308 (1).
To 8). The signal A of λ1 is transmitted to the optical / electrical
8 (1) and the signal B of λ2 is
08 (2), the signal C of λ3 is transmitted to the optical / electrical converter 308 (3), the signal C of λ4 is transmitted to the optical / electrical converter 308 (4), and the signal A of λ5 is optical. The signal B of λ6 is transmitted to the optical / electrical converter 308 (6), the signal C of λ7 is transmitted to the optical / electrical converter 308 (7), and the signal C of λ8 is transmitted to the optical / electrical converter 308 (5). Signal D is light /
It is transmitted to the electric conversion unit 308 (8).

The optical / electrical conversion units 308 (1 to 8) convert the received optical signals A to D into electric signals, and output the electric signals to the corresponding synchronous circuit units 309 (1 to 8) at the subsequent stage. Synchronous circuit section 3
09 (1 to 8) establishes frame synchronization using the A1 and A2 bytes of the input frame and outputs the frame to the selection unit 310.

Selection section 310 selects and outputs one of the same input signals having better transmission quality. That is, the selection unit 310 compares the signal A output from the optical / electrical conversion unit 308 (1) with the signal A output from the optical / electrical conversion unit 308 (5) and outputs the signal with the better transmission quality. 308 (2)
And the signal B output from the optical / electrical converter 308 (6) to output the signal with the better transmission quality.
08 (3) and the signal C output from the optical / electrical conversion unit 308 (6) are compared, and the one with better transmission quality is output, and the optical / electrical conversion unit 308 (4) and the optical / electrical conversion unit 308 ( The signal D output from 8) is compared, and the signal with the better transmission quality is output.

Here, the electrical / optical conversion unit 305 of the transmission unit
Considering the case where (2) has failed, the selector 310 in the receiver selects and outputs the signal B from the optical / electrical converter 308 (6) having good transmission quality. The output signal B is output to the storage unit 311 and the signals A, B, C, and D generated by the transmission path dispersion of the transmission unit.
The difference between the transmission delays is absorbed by storing the signal in the storage unit 311 once.

Thereafter, the 4: 1 restoring unit 312 sequentially reads out the signals A to D from the storage unit 311 based on the unique numbers # 1, # 2, # 3, and # 4 added by the transmission unit, thereby returning the original Restore to signal ABCD. The electrical / optical converter 313 is
The output signal from the 4: 1 restoration unit 312 is converted into an optical signal and a signal of 10 Gb / s is output.

As described above, according to the present embodiment, the same signal is divided and transmitted by the transmitting unit, and the receiving unit selects an arbitrary signal such as a signal having better transmission quality, and uses, for example, a backup line. Then, the signal divided by the transmission unit can be restored to the original signal by the reception unit. In addition, for convenience of explanation, the embodiment has been described with reference to the specific configuration in FIGS. 2 and 3, but the present invention is not limited to this configuration, and can be appropriately changed within the technical idea of the present invention. .

[0056]

As is apparent from the above description, according to the present invention, when a connection error occurs in the cable between the WDM and the transmitting / receiving unit, or when a line setting error occurs in the transmitting unit and the receiving unit. In this case, the transmission unit can accurately and reliably restore the original signal.

Further, according to the present invention, even when a failure occurs in the transmission unit and the quality of the transmission signal is deteriorated, it is possible to compensate the quality at the time of restoration in the forward unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a WDM system according to the present invention.

FIG. 2 is a block diagram for specifically describing an embodiment of a WDM system according to the present invention.

FIG. 3 is a block diagram illustrating another embodiment of the WDM system according to the present invention;

FIG. 4 is a block diagram showing a configuration example of a conventional WDM system.

FIG. 5 is a block diagram for specifically explaining a conventional WDM system.

[Explanation of symbols]

101, 201, 301, 108, 208, 308 Optical / electrical conversion unit 102, 109, 202, 209, 302, 309 Synchronous circuit unit 103 1: n division unit 104, 204, 304 Number addition unit 105, 112, 205, 212, 305, 313 Electric / optical converter 106, 107, 206, 207, 306, 307 W
DM coupler 110, 210, 311 Storage unit 111 n: 1 restoration unit 314 Branch unit

Claims (9)

[Claims] 1. An apparatus in which n signals are received in the order received
(N is an arbitrary natural number) a transmitting device that divides the signal into a plurality of signals, and adds and transmits pertinent sequence information corresponding to each of the divided signals; and receives the n signals, and A WDM system comprising: a receiving device that integrates and restores n signals. 2. The dividing apparatus according to claim 1, wherein the transmitting device divides the received signal from the outside into n signals in the order in which the signal is received, and divides one of the n signals in accordance with the division order in the dividing device. The WDM system according to claim 1, further comprising: n number adding means for inputting and adding the order information to the input signal. 3. The WDM system according to claim 1, wherein the WDM system includes a first WDM coupler that converts the n signals received from the transmitting device into respective predetermined wavelengths and transmits the converted signals. WDM system. 4. The WDM system according to claim 1, wherein the first WD
4. The apparatus according to claim 3, further comprising a second WDM coupler that receives the n signals from the M coupler and transmits the n signals to the receiving device by dividing the signals into the predetermined wavelengths.
A WDM system as described. 5. In the order in which received signals from outside are received, n
(N is an arbitrary natural number) signals, the sequence information is added to each of the divided signals, and each of the n signals to which the order information is added is m (m is an arbitrary natural number) And a transmitting device for branching and transmitting the signals, receiving the n × m signals, selecting one of the m signals for each of the n signals, and selecting the selected n signals And a receiving device that integrates and restores the WDM based on the order information. 6. The transmitting device includes: a dividing unit that divides a received signal from the outside into n signals in the order in which it is received; and one of the n signals corresponding to the division order in the dividing unit. N number adding means for adding the order information to the input signal; and branching each of the n signals to which the order has been added by the number adding means into m signals. , N branching means, and one of the n × m signals output from the branching means is input, the input signal is converted into an optical signal and transmitted.
The WDM system according to claim 5, comprising: n x m first conversion units. 7. The receiving apparatus, comprising: n × m second converting means for converting the n × m signals into an electric signal; and inputting the signal converted by the second converting means. And said n
Selecting means for selecting one signal from m signals for each of the signals; and restoring means for integrating and restoring the n signals selected by the selecting means based on the order. The WDM according to claim 5 or 6, wherein
system. 8. The WDM system according to claim 5, wherein the WDM system includes a first WDM coupler that converts each of the n × m signals received from the transmitting device into a predetermined wavelength and transmits the converted signal. 8. The WDM system according to any one of 7. 9. The WDM system according to claim 1, wherein the first WD
And a second WDM coupler that receives the n × m signals from the M coupler and transmits the n × m signals to the receiving device separately for each of the predetermined wavelengths. 9. The WDM system according to 8.