JPH1168656A - WDM transmission apparatus and WDM transmission system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To configure a standby system with a minimum number of devices and reduce the cost for a redundant configuration. SOLUTION: A wavelength multiplexing transmission means selects (m + n) (n is an integer of 1 or more and m or less) output routes for m (m is an integer of 2 or more) input signals S1 to Sm. It comprises a possible signal selection circuit, m optical transmitters and n optical transmitters having different light source wavelengths, and wavelength multiplexing means for wavelength multiplexing the optical signals of each wavelength and sending them to the optical transmission line. The wavelength division multiplex receiving means is a wavelength separation means for demultiplexing the wavelength division multiplexed optical signal input from the optical transmission line into respective wavelengths, and m optical receivers and n optical receivers for receiving the optical signals of each wavelength. When,
It is composed of a signal selection circuit capable of selecting m output routes for (m + n) input signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplex transmission apparatus having an active system and a protection system, and a wavelength division multiplex transmission system in which the apparatuses are cascaded. In particular, the present invention relates to a configuration for restoring a failure of a device that transmits and receives a wavelength multiplexed optical signal or a failure of an optical transmission line that transmits a wavelength multiplexed optical signal by switching from an active system to a standby system.

[0002]

2. Description of the Related Art FIG. 11 shows an example of the configuration of a conventional wavelength division multiplex transmission apparatus having a working system and a protection system. In the figure, wavelength multiplexing transmission means 51-1 and 51-2, optical transmission paths 52-1 and
52-2, the wavelength division multiplex receiving means 53-1 and 53-2 are independently disposed as a working system and a standby system, respectively. The wavelength-division multiplexing transmission means 51-1 and 51-2 wavelength-multiplex the optical signals of each wavelength with n optical transmitters 54 having different light source wavelengths, and transmit the optical signals to the optical transmission lines 52-1 and 52-2. The optical multiplexer 55 is used. Wavelength multiplex receiving means 53-1;
53-2, an optical demultiplexer 56 for demultiplexing the wavelength multiplexed optical signals input from the optical transmission lines 52-1 and 52-2 into respective wavelengths;
It is composed of n optical receivers 57 that receive optical signals of each wavelength. Here, the working channel is denoted by w, and the standby channel is denoted by p.

[0003]

In a conventional wavelength division multiplexing transmission apparatus, a failure is recovered from an apparatus failure or an optical transmission line failure by switching from an active system to a standby system. The problem at this time will be described with reference to FIG. Here, a two-channel multiplex configuration is shown.

As shown in FIG. 12 (a), when one channel of the wavelength division multiplexing transmission means 51-1 in the working system fails, as shown in FIG. When switching to the multiplex transmission means 51-2, both the optical transmission lines 52-1 and 52-2 become working systems. Such a situation is undesirable because it causes confusion in the maintenance and operation of the system. In order to avoid this, even in the case of a failure of one channel, as shown in FIG. 12 (d), all channels are switched to the standby system at once, and only one system is operated. Further, as shown in FIG. 12 (b), when the active optical transmission line 52-1 fails, all the channels are switched to the standby system as shown in FIG. 12 (d).

[0005] As described above, the conventional wavelength multiplexing transmission apparatus includes:
All of the wavelength division multiplexing transmission means, the optical transmission line, and the wavelength division multiplex reception means are provided with a protection system in addition to the working system. Therefore, in particular, the number of optical transmitters and optical receivers is required twice as many as the number of channels, which has caused a cost increase of the wavelength division multiplex transmission apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wavelength division multiplex transmission apparatus and a wavelength division multiplex transmission system which can configure a standby system with a minimum number of devices and reduce the cost for a duplex configuration.

[0007]

FIG. 1 shows a basic configuration and a switching example of a wavelength division multiplex transmission apparatus according to the present invention. In the figure, the wavelength division multiplexing transmission means 10 receives (m + n) (n + m) input signals S1 to Sm (m is an integer of 2 or more).
Is an integer of 1 to m), m signal transmitters 12-1 to 12-m and n light transmitters 13-1 having different light source wavelengths. ~ 1
3-n and the wavelength division multiplexing of the optical signal of each wavelength.
-1 or wavelength multiplexing means 1 for transmitting to optical transmission line 52-2
4. The wavelength-division multiplex receiving means 20 includes a wavelength separating means 21 for demultiplexing a wavelength-division multiplexed optical signal input from the optical transmission line 52-1 or 52-2 into respective wavelengths, and an m for receiving an optical signal of each wavelength. Optical receivers 22-1 to 22-22
-M and n optical receivers 23-1 to 23-n, and (m
The signal selection circuit 24 is capable of selecting m output routes for (+ n) input signals. Here, the working channel is denoted by w, and the standby channel is denoted by p.

FIG. 1A shows optical transmitters 12-1 to 12-.
m, the optical transmission line 52-1 and the optical receivers 22-1 to 22-m are working systems, and the optical transmitters 13-1 to 13-n and the optical transmission line 5
2-2 shows a normal state in which the optical receivers 23-1 to 23-n operate as a standby system. That is, the wavelength multiplex transmission means 1
The 0 signal selection circuit 11 connects the m input signals S1 to Sm to the optical transmitters 12-1 to 12-m.
Transmits wavelength-multiplexed optical signals output from the optical transmitters 12-1 to 12-m to the optical transmission line 52-1. The wavelength demultiplexing means 21 of the wavelength multiplex receiving means 20 separates the wavelength multiplexed optical signal input from the optical transmission line 52-1 into respective wavelengths and connects them to the optical receivers 22-1 to 22-m. Is output via the signal selection circuit 24.

FIG. 1B shows a state in which the active optical transmitter 12-1 has failed and is switched to the standby optical transmitter 13-1 for operation. That is, the signal selection circuit 11 of the wavelength multiplexing transmission means 10 switches the input signal S1 connected to the optical transmitter 12-1 to the optical transmitter 13-1, and the wavelength multiplexing means 14 transmits the signals from the optical transmitters 12-2 to 12-2. The optical signals output from 12-m and 13-1 are wavelength-multiplexed and transmitted to the optical transmission line 52-1. At this time, the wavelength of the optical signal transmitted from the standby optical transmitter 13-1 is set to the same wavelength as the failed optical transmitter 12-1 or another wavelength.

In the wavelength division multiplexing receiving means 20, the optical receiver 22-1 receives the optical signal according to the wavelength of the optical signal transmitted from the standby optical transmitter 13-1 or, as shown in FIG. , And is output via the signal selection circuit 24.

The same applies to the case where the active optical receiver 22-1 fails. In this case, the optical signal received by the optical receiver 22-1 may be switched to the standby optical receiver 23-1 by the wavelength separating means 21 of the wavelength multiplexing receiving means 20, or the wavelength multiplexing transmitting means 10-1 In this case, the wavelength of the optical signal may be switched so that the standby optical receiver 23-1 receives the optical signal.

FIG. 1C shows a state in which the active optical transmission line 52-1 has failed and is switched to the standby optical transmission line 52-2 for operation. That is, the wavelength multiplexing means 14 of the wavelength multiplexing transmission means 10 wavelength multiplexes the optical signals output from the optical transmitters 12-1 to 12-m and sends out the optical signals to the optical transmission line 52-2. The wavelength division unit 21 of the wavelength division multiplex reception unit 20 separates the wavelength division multiplexed optical signal input from the optical transmission line 52-2 into respective wavelengths and connects them to the optical receivers 22-1 to 22-m.

As described above, in the wavelength division multiplex transmission apparatus of the present invention, in m channel wavelength division multiplex transmission, a standby system of an optical transmitter and an optical receiver is provided for n channels, and both the apparatus failure and the optical transmission path failure are caused. It is made to be able to cope.
The value of n is determined in a range from 1 to m according to the failure occurrence situation and the recovery request. That is, it is not always necessary to prepare the same number of the active system and the standby system, and the standby system can be configured with a minimum configuration.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 2 shows a first embodiment of the wavelength multiplexing transmission means 10 and an example of switching for a failure of the optical transmitter. Here, a case where m = 3 and n = 1 in the basic configuration of FIG. 1 will be described.

In the figure, input signals S1, S2, S3
Are optical transmitters 12-1 to 12-12 via a signal selection circuit 11.
-3 or 13 is input. The output of each optical transmitter is supplied to the optical coupler 1 via optical switches 15-1 to 15-4.
6-1 or the optical coupler 16-2,
2-1 or the optical transmission path 52-2.

In the normal state, as shown in FIG. 2A, the signal selection circuit 11 connects the input signals S1, S2, S3 to the optical transmitters 12-1 to 12-3, and outputs the signals from the respective optical transmitters. The optical signals of the wavelengths λ1, λ2, λ3 to be
15-3, and is connected to the optical coupler 16-1, wavelength-multiplexed and transmitted to the optical transmission line 52-1.

When the optical transmitter 12-2 fails, as shown in FIG. 2B, the signal selection circuit 11 outputs the input signal S2.
Is connected to the optical transmitter 13, and the optical signals of the wavelengths λ1, λ3, λa output from the optical transmitters are connected to the optical switches 15-1 to 15-1
The optical coupler 16-1 is connected to the optical coupler 16-1 via 5-4, wavelength-multiplexed, and transmitted to the optical transmission line 52-1. In this configuration, since the optical switch 15 and the optical coupler 16 have no wavelength dependency, the wavelength λa of the optical transmitter 13 is arbitrary. The optical coupler 1
In the case where an optical multiplexer having a wavelength dependency is used instead of 6, the wavelength λa needs to be selected to a wavelength suitable for the optical multiplexer.

FIG. 3 shows a first embodiment of the wavelength division multiplex receiving means 20 and an example of switching of the wavelength division multiplex transmission means 10 in case of an optical transmitter failure (m = 3, n = 1).

In the figure, a wavelength-division multiplexed optical signal input from the optical transmission line 52-1 or 52-2 is demultiplexed into optical signals of each wavelength by the optical demultiplexers 25-1 and 25-2. , One of the optical signals is an optical switch 26-1 to 26-4.
Through the optical receivers 22-1 to 22-3 and 23. The output of each optical receiver is output via the signal selection circuit 24. As the optical demultiplexer 25, a dielectric multilayer optical filter, an array waveguide diffraction grating (AW
G), a fiber grating and an optical circulator can be used.

FIG. 3A shows a wavelength multiplex receiving means 20 corresponding to a case where the wavelength multiplex transmitting means 10 is in a normal state (FIG. 2A).
Shows the connection state of. That is, the wavelength division multiplexed optical signal input from the optical transmission line 52-1 is demultiplexed into optical signals of each wavelength by the optical demultiplexer 25-1, and the optical signals of wavelengths λ1 to λ3 are demultiplexed into the optical switches 26-1 to 26-26. -3 through the optical receivers 22-1 to 22-
Enter 3 The signal selection circuit 24 includes an optical receiver 22-1.
22-3 are output.

FIG. 3B shows the connection state of the wavelength division multiplex receiving means 20 corresponding to the case where the optical transmitter 12-2 of the wavelength division multiplex transmission means 10 has failed (FIG. 2B). That is, the wavelength division multiplexed optical signal input from the optical transmission line 52-1 is converted into the optical demultiplexer 2
At 5-1 the optical signal of each wavelength is demultiplexed, and the wavelengths λ1, λ3, λ
The optical signal of "a" is transmitted to the optical switches 26-1, 26-3, 26-4.
To the optical receivers 22-1, 22-3, and 23 via. The signal selection circuit 24 includes the optical receivers 22-1, 23, 2
The output signal of 2-3 is output. If the wavelength λa of the optical signal transmitted from the optical transmitter 13 is λ2, FIG.
The configuration of the wavelength division multiplex receiving means 20 shown in FIG.

(Example of Switching of WDM Reception Unit 20 for Optical Receiver Failure)
If 2 fails, then: In the configuration shown in FIG. 3B, an optical signal having a wavelength λ2 that is split from the optical splitter 25-1 to the optical receiver 22-2 is transmitted to the standby optical receiver 23. The configuration of the optical demultiplexer that makes this possible is as shown in FIG. 4A, where the optical splitter 31 and the optical filters 32-1 to 32-1 are used.
32-3 and a variable transmission wavelength optical filter 33, and the transmission wavelength of the variable transmission wavelength optical filter 33 is adjusted to be λ2. Alternatively, as shown in FIG. 4 (b), the transmission wavelength tunable optical filter 33-4 is constituted by the optical splitter 31 and the transmission wavelength tunable optical filters 33-1 to 33-4 and adjusted so that the transmission wavelength of the transmission wavelength tunable optical filter 33-4 becomes λ2. I do.

Alternatively, as in the case where the optical transmitter 12-2 of the wavelength division multiplexing transmitting means 10 has failed, the optical signal of the wavelength λa is transmitted from the optical transmitter 13 and the optical signal is transmitted to the optical receiver 23.
May be received.

FIG. 5 shows a second embodiment of the wavelength multiplexing transmission means 10 and an example of switching for a failure of the optical transmitter. Here, a case where m = 3 and n = 1 in the basic configuration of FIG. 1 will be described.

In the figure, input signals S1, S2, S3
Are optical transmitters 12-1 to 12-12 via a signal selection circuit 11.
-3 or 13 is input. The output of each optical transmitter is an arrayed waveguide grating (hereinafter referred to as “AWG”) 1
7 from the predetermined output port of the AWG 17 and the optical transmission line 52-1 or the optical transmission line 52-.
2 is sent.

The AWG 17 is a wavelength-dependent optical multiplexer whose output port is determined according to the input port and the input wavelength. Here, the wavelengths λ1, λ2, λ
It is assumed that when optical signals of 3, λ4 are input, a wavelength-division multiplexed optical signal obtained by multiplexing them is output to an output port connected to the optical transmission line 52-1.

In the normal state, as shown in FIG. 5A, the signal selection circuit 11 connects the input signals S1, S2, S3 to the optical transmitters 12-1 to 12-3, and outputs the signals from the respective optical transmitters. The optical signals of the wavelengths λ1, λ2, λ3 are wavelength-multiplexed by the AWG 17 and transmitted to the optical transmission line 52-1.

When the optical transmitter 12-2 fails, as shown in FIG. 5B, the signal selection circuit 11 outputs the input signal S2.
Is connected to the optical transmitter 13, and the optical signals of the wavelengths λ1, λ3, λ4 output from the respective optical transmitters are wavelength-multiplexed by the AWG 17 and transmitted to the optical transmission line 52-1. In this configuration, the wavelength of the optical transmitter 13 is limited to λ4.

Further, as shown in FIG. 5C, the optical transmitter 1
3 outputs an optical signal of the same wavelength λ2 as that of the failed optical transmitter 12-2, the optical signal of the wavelength λ2 output from the optical transmitter 13 via the signal selection circuit 18 is AWG1.
7 to be connected to the second input port.
As a result, the state becomes the same as the state in which the optical signal of the wavelength λ2 is output from the optical transmitter 12-2, and is transmitted from the AWG 17 to the optical transmission line 52-1.

FIG. 6 shows a second embodiment of the wavelength division multiplex receiving means 20 and an example of switching of the wavelength division multiplex transmission means 10 with respect to an optical transmitter failure (m). = 3, n = 1).

In the figure, a wavelength-division multiplexed optical signal input from the optical transmission line 52-1 or 52-2 is AWG
The optical receiver 22- is input to a predetermined input port 27, demultiplexed into optical signals of respective wavelengths, and output from respective predetermined output ports.
1 to 22-3 and 23. The output of each optical receiver is output via the signal selection circuit 24. This AWG
Reference numeral 27 denotes a device that functions as a wavelength-dependent optical demultiplexer by exchanging input / output ports of the AWG 17 used in the wavelength multiplexing transmission means 10.

FIG. 6A shows a wavelength multiplex receiving means 20 corresponding to a case where the wavelength multiplex transmitting means 10 is in a normal state (FIG. 5A).
Shows the connection state of. That is, the wavelength-division multiplexed optical signal input from the optical transmission line 52-1 is split into optical signals of each wavelength by the AWG 27, and the optical signals of the wavelengths λ1 to λ3 are converted into the optical receiver 22-1.
To 22-3. The signal selection circuit 24 outputs output signals of the optical receivers 22-1 to 22-3.

FIG. 6B shows the connection state of the wavelength division multiplex receiving means 20 corresponding to the case where the optical transmitter 12-2 of the wavelength division multiplex transmission means 10 has failed (FIG. 5B). That is, the wavelength multiplexed optical signal input from the optical transmission line 52-1 is converted into the AWG27 signal.
The optical signals of wavelengths λ1, λ3, and λ4 are input to the optical receivers 22-1, 22-3, and 23, respectively.
The signal selection circuit 24 includes the optical receivers 22-1, 23, 22-
3 is output. As shown in FIG. 5C, the optical transmitter 12-2 breaks down, and the wavelength λ2
6A can be handled by the configuration shown in FIG. 6A.

(Example of Switching for Failure of Optical Receiver in Wavelength Division Multiplexing Receiver 20)
If 2 fails, then: In the configuration shown in FIG. 6B, the optical transmitter 12-2 of the
Causes the optical transmitter 13 to transmit the optical signal of the wavelength λ4 and causes the optical receiver 23 to receive the optical signal in the same manner as in the case where the optical transmitter 13 fails and the optical signal of the wavelength λ4 is transmitted from the optical transmitter 13. I do. The signal selection circuit 24 includes the optical receivers 22-1 and 22-2.
3, 22-3 are output.

In the configuration of each embodiment of the wavelength multiplex transmission means 10 and the wavelength multiplex reception means 20 described above, FIG.
May be combined with the wavelength division multiplexing transmission means 10 shown in FIG. 6 and the wavelength division multiplex transmission means 10 shown in FIG. 5 and the wavelength division multiplex reception means 20 shown in FIG.

(Example of Switching for Optical Transmission Line Failure) FIG.
An example of switching of the wavelength multiplexing transmission means 10 for an optical transmission line failure will be described. Here, the configuration of the wavelength division multiplexing transmission means 10 is shown in FIG.
This is the same as in the first embodiment. Although not shown, the configuration of the wavelength division multiplex receiving means 20 is the same as that of FIG. 3 (first embodiment).

In the figure, input signals S1, S2, S3
Are optical transmitters 12-1 to 12-12 via a signal selection circuit 11.
-3 or 13 is input. The output of each optical transmitter is supplied to the optical coupler 1 via optical switches 15-1 to 15-4.
6-1 or the optical coupler 16-2,
2-1 or the optical transmission path 52-2.

In the normal state, as shown in FIG. 7A, the signal selection circuit 11 connects the input signals S1, S2, S3 to the optical transmitters 12-1 to 12-3, and outputs the signals from the respective optical transmitters. The optical signals of the wavelengths λ1, λ2, λ3 to be
15-3, and is connected to the optical coupler 16-1, wavelength-multiplexed and transmitted to the optical transmission line 52-1.

When the optical transmission line 52-1 breaks down, the optical switches 15-1 to 15-3 switch the wavelengths output from the optical transmitters 12-1 to 12-3 as shown in FIG. λ1,
The optical signals of λ2 and λ3 are connected to the optical coupler 16-2, wavelength-multiplexed, and transmitted to the optical transmission line 52-2.

The response to the failure of the optical transceiver shown in FIGS. 2 and 3 and the response to the failure of the optical transmission line shown in FIG. 7 are independent of each other, and it is possible to combine both.
That is, the active optical transmitter 12-2 or the active optical receiver 22-2 fails, and the optical transmitter 13 or the optical receiver 23
And the switching to the spare optical transmission line 52-2 due to the failure of the working optical transmission line 52-1 is performed by the signal selection circuit 1.
1, 24 and optical switches 15-1 to 15-4, 26-1 to
It is possible to respond simultaneously by the operation of 26-4.

(Example of Switching for Optical Transmission Line Failure) FIG.
An example of switching of the wavelength multiplexing transmission means 10 for an optical transmission line failure will be described. Here, the configuration of the wavelength multiplexing transmitting means 10 is shown in FIG.
This is the same as in the second embodiment. Although not shown, the configuration of the wavelength division multiplexing receiving means 20 is the same as that of FIG. 6 (second embodiment).

In the figure, input signals S1, S2, S3
Are optical transmitters 12-1 to 12-12 via a signal selection circuit 11.
-3 or 13 is input. The output of each optical transmitter is connected to a predetermined input port of the AWG 17,
The signal is transmitted from the predetermined 17 output ports to the optical transmission line 52-1 or 52-2.

The AWG 17 is a wavelength-dependent optical multiplexer whose output port is determined according to the input port and the input wavelength. Here, the wavelengths λ1, λ2, λ
It is assumed that when optical signals of 3, λ4 are input, a wavelength-division multiplexed optical signal obtained by multiplexing them is output to an output port connected to the optical transmission line 52-1. Further, when optical signals of wavelengths λ4, λ1, λ2, λ3 are input to the four input ports, a wavelength multiplexed optical signal obtained by multiplexing them is transmitted to the optical transmission line 5.
It is assumed that the data is output to an output port connected to 2-2.

In the normal state, as shown in FIG. 8A, the signal selection circuit 11 connects the input signals S1, S2, S3 to the optical transmitters 12-1 to 12-3, and outputs the signals from the respective optical transmitters. The optical signals of the wavelengths λ1, λ2, λ3 are wavelength-multiplexed by the AWG 17 and transmitted to the optical transmission line 52-1.

When the optical transmission line 52-1 is out of order, as shown in FIG. 8B, when the wavelengths of the optical transmitters 12-1 to 12-3 are switched to λ4, λ1, and λ2, each optical transmission The optical signal output from the device is wavelength-multiplexed by the AWG 17 and transmitted to the optical transmission line 52-2.

As shown in FIG. 8C, the optical transmitter 1
Assuming that the wavelengths of 2-1 to 12-3 remain unchanged at λ1, λ2, and λ3, the optical signals output from the optical transmitters 12-1 to 12-3 via the signal selection circuit 18 are converted to AWG 17 signals.
Is switched to be connected to the second, third, and fourth input ports. Thereby, the optical signal wavelength-multiplexed by the AWG 17 can be transmitted to the optical transmission line 52-2.

The response to the failure of the optical transceiver shown in FIGS. 5 and 6 and the response to the failure of the optical transmission line shown in FIG. 8 are independent of each other, and it is possible to combine both.
That is, the active optical transmitter 12-2 or the active optical receiver 22-2 fails, and the optical transmitter 13 or the optical receiver 23
To the spare optical transmission line 52-2 due to the failure of the working optical transmission line 52-1 and the spare optical transmission line 52-2.
1-12-3, 13 wavelength or signal selection circuits 11, 1
The operations can be simultaneously performed by the operations 8 and 24.

(Application example to optical add / drop node apparatus) By combining the wavelength multiplex transmission means 10 and the wavelength multiplex reception means 20 of the wavelength division multiplex transmission apparatus of the present invention, the optical add / drop node apparatus shown in FIG. Nodes).

In FIG. 9A, the wavelength division multiplexed optical signal input from the optical transmission line 52 is demultiplexed into each wavelength by the wavelength separation means 21 of the wavelength division multiplex reception means 20, and a part of the optical signal is directly used as the wavelength. The signal is input to the wavelength multiplexing means 14 of the multiplex transmission means 10 and transmitted to the next-stage optical transmission line 52. Here, the wavelength separating means 21 is the optical demultiplexer 25 and the optical switch 26 shown in FIG. 3, or the AWG 27 shown in FIG. The wavelength multiplexing means 14 includes the optical switch 15 and the optical coupler 1 shown in FIG.
6, or AWG 17 shown in FIG. Such nodes 41 are cascaded through an optical transmission line 52 as shown in FIG. 9 (b), and a wavelength division multiplexing transmission system capable of dropping / adding an optical signal of a predetermined wavelength is configured for each node. You.

(Utilization of Wavelength λa Output from Standby Optical Transmitter 13) In FIGS. 2 and 7, an optical signal (extra traffic, dummy signal) of wavelength λa is output from the standby optical transmitter 13. Is connected to the optical coupler 16-1 via the optical switch 15-4, and wavelength-multiplexes the wavelength-multiplexed optical signal transmitted to the optical transmission line 52-1. The optical signal having the wavelength λa transmitted to the optical transmission line 52-1 in this manner is terminated by the optical receiver 23 of the wavelength division multiplex receiving means 20 shown in FIG.

5 and 8, an optical signal of wavelength λ4 (extra traffic,
A dummy signal) is output, input to a predetermined input port of the AWG 17, and wavelength-multiplexed into a wavelength-division multiplexed optical signal transmitted to the optical transmission line 52-1. The optical signal of wavelength λ4 sent to the optical transmission line 52-1 in this manner is terminated by the optical receiver 23 of the wavelength division multiplexing receiving means 20 shown in FIG.

FIG. 10 shows a configuration example of a wavelength division multiplexing transmission system in which three nodes are connected in a ring. Node 41
-1 is transmitted to the node 41-2 via the relay optical amplifier 42-1 using an optical signal of wavelength λ3. The signal is transmitted from the node 41-2 to the node 41-1 via the relay optical amplifier 42-2 and the node 41-3 using the optical signal of the wavelength λ3. At this time, the node 41-3 passes the optical signal of the wavelength λ3 as it is.

From the node 41-2 to the node 41-3,
The optical signal having the wavelength λ1 is transmitted via the relay optical amplifier 42-2. An optical signal of wavelength λ1 is transmitted from the node 41-3 to the node 41-2 via the node 41-1 and the relay optical amplifier 42-1. At this time, the node 41-1 passes the optical signal of the wavelength λ1 as it is.

From the node 41-3 to the node 41-1,
It is transmitted using an optical signal of wavelength λ2. Node 41-1
Is transmitted to the node 41-3 via the relay optical amplifier 42-1, the node 41-2, and the relay optical amplifier 42-2 using the optical signal of the wavelength λ2. At this time, node 41
At -2, the optical signal of the wavelength λ2 is passed as it is.

Here, λa is prepared between the nodes as a backup wavelength. This optical signal is transmitted from each node and terminated at the next node as described above. Therefore, gain control and / or output light level control of the relay optical amplifiers 42-1 and 42-2 can be performed using the optical signal of the wavelength λa. That is, since each relay optical amplifier only needs to monitor one wavelength, gain control and the like can be performed with a relatively simple circuit.

In the wavelength division multiplexing transmission system shown in FIG. 10, for example, a failure occurs in the optical transceiver of the optical signal of the wavelength λ2 transmitted from the node 41-1 to the node 41-3, and the optical signal of the wavelength λa If switching, node 4
In step 1-2, control is performed so that the optical signal of the wavelength λa passes, or the optical signal of the wavelength λa that has been terminated is once again sent to the node 41
3 to be transmitted.

[0057]

As described above, the wavelength division multiplex transmission apparatus according to the present invention is provided with a minimum necessary number of spare optical transmitters constituting the wavelength division multiplex transmission means and the optical receiver constituting the wavelength division multiplex reception means. Thus, it is possible to realize a standby system for device failure and optical transmission line failure. As a result, it is possible to reduce costs for a duplex configuration.

Further, in the wavelength division multiplex transmission system of the present invention, various controls between the wavelength division multiplex transmission apparatuses can be realized by using the optical signal of the standby system.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration and a switching example of a wavelength division multiplex transmission device of the present invention.

FIG. 2 is a diagram showing a first embodiment of the wavelength division multiplexing transmission means 10 and an example of switching when an optical transmitter fails.

FIG. 3 is a diagram showing a first embodiment of the wavelength division multiplex receiving means 20 and a switching example.

FIG. 4 is a diagram showing a configuration example of an optical demultiplexer according to the first embodiment of the wavelength division multiplex receiving means 20.

FIG. 5 is a diagram showing a second embodiment of the wavelength division multiplexing transmission means 10 and a switching example.

FIG. 6 is a diagram showing a second embodiment of the wavelength division multiplex receiving means 20 and a switching example.

FIG. 7 is a diagram showing an example of switching of the wavelength division multiplexing transmission means 10 for an optical transmission line failure.

FIG. 8 is a diagram showing an example of switching of the wavelength division multiplexing transmission means 10 for an optical transmission line failure.

FIG. 9 is a diagram illustrating a configuration example of an optical add / drop node device;

FIG. 10 is a diagram illustrating a configuration example of a wavelength division multiplexing transmission system in which three nodes are connected in a ring.

FIG. 11 is a diagram showing a configuration example of a conventional wavelength division multiplexing transmission device including a working system and a protection system.

FIG. 12 is a diagram illustrating a problem of a conventional wavelength division multiplex transmission device.

[Explanation of symbols]

 Reference Signs List 10 wavelength multiplexing transmitting means 11 signal selecting circuit 12, 13 optical transmitter 14 wavelength multiplexing means 15 optical switch 16 optical coupler 17 arrayed waveguide grating (AWG) 18 signal selecting circuit 20 wavelength multiplexing receiving means 21 wavelength separating means 22, 23 Optical receiver 24 Signal selection circuit 25 Optical demultiplexer 26 Optical switch 27 Arrayed waveguide diffraction grating (AWG) 31 Optical splitter 32 Optical filter 33 Transmission wavelength variable optical filter 51 Wavelength multiplexing transmitting means 52 Optical transmission path 53 Wavelength multiplexing receiving means 54 optical transmitter 55 optical multiplexer 56 optical demultiplexer 57 optical receiver

Claims (9)

[Claims] 1. A wavelength division multiplexing transmission device comprising a wavelength division multiplex transmission means for transmitting and receiving a wavelength division multiplexed optical signal via a working optical transmission line or a protection optical transmission line, and a wavelength division multiplex reception means, For m input signals (m is an integer of 2 or more), (m +
n) (n is an integer of 1 or more and m or less) output signal selection circuits, and optical signals connected to each output terminal of the signal selection circuit and having different wavelengths according to the output signals. M active optical transmitters and n standby optical transmitters, and the optical signals output from the active optical transmitter and the standby optical transmitter are wavelength-multiplexed, and the active optical transmission line or the standby A wavelength division multiplexing transmission device comprising: a wavelength division multiplexing means for outputting to a light transmission path. 2. The wavelength division multiplexing transmission device according to claim 1, wherein the signal selection circuit connects m input signals to m working optical transmitters in a normal state, and selects the m working optical transmitters. When i (where i is an integer of 1 or more and n or less) are switched to the standby optical transmitter, the input signal connected to the working optical transmitter is switched to i standby optical transmitters. Characteristic wavelength multiplex transmission equipment. 3. The working optical transmitter according to claim 1, wherein the wavelength multiplexing means wavelength multiplexes the optical signal output from the working optical transmitter in a normal state and outputs the multiplexed signal to an optical transmission line. When a standby optical transmitter is used instead of a part of the optical transmitter, the optical signals output from the corresponding active optical transmitter and standby optical transmitter are wavelength-multiplexed and output to an optical transmission line. Wavelength multiplexing transmission device. 4. The wavelength-division multiplexing transmission device according to claim 3, wherein the wavelength-division multiplexing means has a wavelength dependency in which an output port is determined according to an input port and an input wavelength, and is replaced with a part of the working optical transmitter. A wavelength division multiplexing transmission apparatus, comprising: a signal selection circuit for switching an input port of the wavelength division multiplexing means to which an optical signal output from the standby optical transmitter is connected when a standby optical transmitter is used. . 5. A wavelength division multiplexing transmission device comprising a wavelength division multiplex transmission means for transmitting and receiving a wavelength division multiplexed optical signal via a working optical transmission line or a protection optical transmission line, and a wavelength division multiplex reception means, Wavelength demultiplexing means for demultiplexing a wavelength multiplexed optical signal input from the working optical transmission line or the standby optical transmission line into optical signals of respective wavelengths; connected to each output terminal of the wavelength demultiplexing means, corresponding to each output terminal M (m is an integer of 2 or more) active optical receivers and n (n is an integer of 1 or more and m or less) standby optical receivers for receiving optical signals of respective wavelengths to be transmitted; Wavelength multiplexing transmission, comprising: a receiver and a signal selection circuit capable of selecting m output routes for (m + n) input signals output from the n standby optical receivers. apparatus. 6. The wavelength division multiplexing transmission apparatus according to claim 5, wherein the signal selection circuit outputs an output signal of the m active optical receivers in a normal state, and outputs i output signals of the m active optical receivers. When (i is an integer of 1 or more and n or less) is switched to the standby optical receiver, the output signal of the working optical receiver is switched to the output signal of the standby optical receiver and output. Multiplex transmission equipment. 7. The wavelength division multiplexing transmission device according to claim 5, wherein the wavelength demultiplexing unit normally demultiplexes the wavelength division multiplexed optical signal from the working optical transmission line into respective wavelengths and inputs the wavelength division multiplexed optical signal to a working optical receiver. When using a spare optical transmitter instead of a part of the working optical transmitter,
Alternatively, when a spare optical receiver is used instead of a part of the working optical receiver, the wavelength division multiplexed optical signal input from the working optical transmission line is demultiplexed into each wavelength, and the corresponding working optical receiver and spare A wavelength-division multiplexing transmission device having a configuration for inputting to an optical receiver. 8. The wavelength multiplexing receiving means according to claim 5, which receives a wavelength multiplexed optical signal input from an optical transmission line, and transmits the wavelength multiplexed optical signal to be output to the optical transmission line. In a wavelength multiplex transmission system in which a plurality of wavelength multiplex transmission devices having wavelength multiplex transmission means and one or more relay optical amplifiers disposed between the wavelength multiplex transmission devices are cascaded, A wavelength division multiplexing transmission system wherein the wavelengths of the optical signals transmitted from the standby optical transmitter to the standby optical receiver (standby wavelengths) are the same. 9. The wavelength multiplex transmission system according to claim 8, wherein an optical signal of a spare wavelength is monitored between each wavelength multiplex transmission device,
A wavelength division multiplexing transmission system having a configuration for controlling gain control and / or output light level control of a repeater optical amplifier.