JP2000115132A - Light wavelength multiplex transmitter and transmission method, light wavelength multiplex receiver and reception method and light wavelength multiplex transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of suppressing the increase of equipment as much as possible even in the case of redundant constitution by providing a wavelength variable light transmission circuit capable of changing the wavelength of signal light to be sent out and a supervisory and controlling circuit for controlling a light transmission circuit and the wavelength variable light transmission circuit. SOLUTION: In the state where no fault is generated in light reception circuits 7-9 the supervisory and controlling circuit 12 outputs control signals for selecting the output signals of the light reception circuits 7-9 to selectors 31-33 and communication is performed by the light reception circuits 7-9. For instance, when the fault is generated in the light reception circuit 8 for receiving the optical signals of the wavelength λk, the fault of the light reception circuit 8 is detected in the supervisory and controlling circuit 12, and the supervisory and controlling circuit 12 outputs the control signals for setting a signal reception wavelength to the wavelength λk to the wavelength variable light reception circuit 10 and outputs the control signals for selecting the signals of a branching part 34 to the selector 32. The signals of the wavelength λk are received through the wavelength variable light reception circuit 10 instead of the light reception circuit 8 and redundant changeover is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical wavelength division multiplexing transmitter, an optical wavelength division multiplexing receiver, and an optical wavelength division multiplexing transmission apparatus, and more particularly to an optical wavelength division multiplexing transceiver having a redundant configuration.

[0002]

2. Description of the Related Art In an optical wavelength division multiplexing transmission terminal equipment, an optical transmission signal capable of accommodating a large-capacity line per wavelength and an optical signal of a plurality of different wavelengths using an optical wavelength division multiplexing technique are further converted. The super-large capacity transmission is realized by multiplexing.

For example, as shown in FIG. 5, in an optical wavelength division multiplexing transmission terminal apparatus for performing optical wavelength division multiplexing using optical signals of n wavelengths, an optical transmitting circuit and an optical receiving circuit corresponding to a specific wavelength are respectively provided. There are n units. On the transmission side, n signals having different wavelengths output from n optical transmission circuits are optically multiplexed in the optical multiplexer 47 and transmitted. On the receiving side, the received optical wavelength division multiplexed signal is distributed to n optical receiving circuits by the optical demultiplexer 51, and each individual optical receiving circuit separates an optical signal of a unique wavelength by an optical wavelength selecting means such as an optical filter. Demultiplexed and receiving.

[0004] The above-mentioned conventional optical transmission circuit and optical receiving circuit have a large number of lines accommodated therein and have a remarkable effect upon line disconnection. Therefore, high reliability is realized by taking a redundant configuration. That is, each optical transmitting circuit and optical receiving circuit always includes a spare optical transmitting circuit and optical receiving circuit. On the optical transmission side, a selector is arranged for each wavelength, and selects an output of the optical transmission circuit and a backup optical transmission circuit. The output from each selector is multiplexed by an optical multiplexer and input to an optical transmission line. On the optical receiving side, the wavelength division multiplexed signal light branched by the number of wavelengths by the optical demultiplexer is input to a branching unit provided corresponding to each optical receiving circuit. The splitter splits the wavelength multiplexed signal light into two outputs, and these two outputs are input to an optical receiving circuit and a spare optical receiving circuit.

[0005]

However, in the conventional optical wavelength division multiplexing transmission apparatus having a redundant configuration, a spare circuit is provided for each of the optical transmission circuit and the optical reception circuit corresponding to each wavelength to be wavelength multiplexed. . Therefore, in order to perform n-wavelength optical wavelength division multiplexing transmission, 2 × n optical transmission circuits and optical reception circuits are required, and there is a problem that the scale of the equipment increases significantly with an increase in the number of wavelength division multiplexing. .

An object of the present invention is to provide an optical wavelength division multiplexing transmission apparatus capable of minimizing the increase in equipment even when the optical wavelength division multiplexing transmission apparatus has a redundant configuration.

[0007]

SUMMARY OF THE INVENTION An optical wavelength division multiplexing transmitter according to the present invention comprises a plurality of optical transmission circuits for transmitting signal lights of specific wavelengths, and an optical multiplexer for multiplexing a plurality of signal lights. The wavelength multiplexing transmitter includes a wavelength tunable optical transmission circuit that can change the wavelength of the signal light to be transmitted, and a monitoring control circuit that controls the optical transmission circuit and the wavelength tunable optical transmission circuit. Further, a branching unit arranged corresponding to each optical transmission circuit and branching a main signal into two, and one main signal output from each branching unit is received and input by a control signal from a monitoring control circuit. And a selector for selecting one of the plurality of main signals and transmitting the selected main signal to the variable wavelength optical transmission circuit.

An optical wavelength division multiplexing receiver according to the present invention is an optical wavelength division multiplexing receiver comprising an optical demultiplexer for demultiplexing a plurality of signal lights and a plurality of optical receiving circuits for respectively receiving signal lights of specific wavelengths. There is provided a wavelength variable optical receiving circuit capable of changing the wavelength of the signal light to be received, and a monitoring control circuit for controlling the optical receiving circuit and the wavelength variable optical receiving circuit. Further, a branching unit for branching the output of the wavelength tunable optical transmitting circuit into a plurality of outputs, and one of the output of the corresponding optical receiving circuit and the output of the branching unit provided corresponding to each optical receiving circuit. And a selector for selecting and outputting one of the inputs according to a control signal from the monitoring control circuit. In addition, an optical wavelength multiplex transmission device including the optical wavelength multiplex transmitter and the optical wavelength multiplex receiver can be configured.

As an optical transmission method for wavelength-multiplexing and transmitting signal light of a plurality of wavelengths, a plurality of optical transmission circuits are monitored, and when it is detected that a failure has occurred in the optical transmission circuit,
It is possible to obtain an optical transmission method in which the function of the optical transmission circuit is stopped and the signal light of the wavelength transmitted from the optical transmission circuit is transmitted from the variable wavelength optical transmission circuit. In addition, as an optical receiving method for receiving wavelength multiplexed signal light, a plurality of optical receiving circuits are monitored, and when it is detected that a failure has occurred in the optical receiving circuit,
An optical transmission method in which the function of the optical receiving circuit is stopped and the wavelength-variable optical receiving circuit receives the signal light having the wavelength received by the optical receiving circuit is obtained.

With such a configuration, in the present invention, it is possible to cope with a failure of any wavelength by simply arranging one spare circuit on each of the transmitting side and the receiving side for n wavelengths. A simplified optical transmission device can be realized.

[0011]

1 and 2 show an example of the basic configuration of the present invention.

The optical wavelength division multiplexing transmitter shown in FIG. 1 has n optical transmission circuits 1 to 3 each having a unique optical transmission wavelength, and can change the optical transmission wavelength over the entire wavelength range used for transmission. The wavelength tunable optical transmission circuit 4 is provided. The tunable optical transmission circuit 4 can be realized by, for example, a combination of a tunable light source and an external optical modulator. The optical multiplexer 5 has these n
The optical signals output from the +1 optical transmission circuits are multiplexed and wavelength-multiplexed, and output to the transmission line. The monitoring control circuit 11 monitors faults and controls output of the fixed-wavelength optical transmission circuits 1 to 3 and the wavelength-variable optical transmission circuit 4, and sets a wavelength for the wavelength-variable optical transmission circuit 4.

The optical wavelength division multiplexing receiver shown in FIG. 2 includes an optical demultiplexer 6 for splitting an optical signal received from a transmission line into n + 1 optical signals. Each of the n + 1 branched optical signals is input to n optical receiving circuits 7 to 9 having a unique receiving wavelength and one wavelength variable optical receiving circuit 10 capable of changing the receiving wavelength. The wavelength tunable optical receiving circuit 10 can be realized by, for example, a combination of a wavelength tunable filter capable of changing a transmission wavelength and an optical receiver. The monitoring control circuit 12 monitors the occurrence of a failure in the fixed-wavelength optical receiving circuits 7 to 9, and also stops and starts the wavelength-variable optical receiving circuit 10 and sets the wavelength.

During normal operation, the supervisory control circuits 11 and 12
Control, the optical transmission circuits 1 to 3 and the optical reception circuits 7 to 9 respectively corresponding to n wavelengths are used, and the tunable optical transmission circuit 4 and the tunable optical reception circuit 10 stop operating as standby systems. ing. When a failure occurs in the optical transmission circuit 2 corresponding to the k-th wavelength, the monitoring control circuit 11
Detects a failure in the optical transmission circuit 2, sets the optical transmission wavelength of the tunable optical transmission circuit 4 to the optical wavelength of the k-th optical transmission circuit 2 in which the failure has occurred, and starts up. Monitoring control circuit 11
At this time, the output of the optical signal of the optical transmission circuit 2 is stopped.
Since the wavelength tunable optical transmission circuit 4 supports all the wavelengths from the first to the n-th wavelength, it operates as a backup circuit even if a failure occurs in any of the optical transmission circuits.

An optical receiving circuit 8 corresponding to the k-th wavelength
When a failure occurs in the monitoring control circuit 12
Detects the failure of the optical receiving circuit 8, sets the optical receiving wavelength of the variable wavelength optical receiving circuit 10 to the optical wavelength of the k-th optical receiving circuit 8 in which the failure has occurred. Since the wavelength tunable optical receiving circuit 10 supports all the first to n-th wavelengths, it can operate as a backup circuit even if any optical receiving circuit fails.

FIG. 3 shows a detailed configuration example of the optical wavelength multiplexing transmitter.

The main signal processing circuits 25 to 27 are circuits for multiplexing low-speed signals and processing overhead. Outputs of the n main signal processing circuits 25 to 27 are input to n branch sections 21 to 23, respectively. The branching units 21 to 23 divide the input main signal into two and output.

The first outputs of the branch units 21 to 23 are input to n optical transmission circuits 1 to 3, respectively. Optical transmission circuit 1
Reference numeral 3 outputs an optical signal having an optical transmission wavelength unique to each of λ1 to λn. In addition, the optical transmission circuits 1 to 3 are connected to the monitoring control circuit 11, and the monitoring control circuit 11 controls the output of the fault information and the control of the optical output.

The optical signal outputs of the n optical transmission circuits 1 to 3 are input to the optical multiplexer 13. The optical multiplexer 13 optically multiplexes the inputted optical signals of n wavelengths and outputs the multiplexed optical signals. As the optical multiplexer 13, an optical multiplexer having n or more input ports independent of wavelength is used. In order to remove noise from each input port and reduce coupling loss between input and output, AWG (Ar
An optical multiplexer having wavelength selectivity, such as layered waveguide grating, may be used.

The second outputs of the branches 21 to 23 are input to the selector 24, respectively. The selector 24 has an n: 1 switching function, selects one signal designated by a control signal from n signal inputs, and outputs the selected signal. The control signal of the selector 24 is sent from the monitoring control circuit 11. The signal output of the selector 24 is input to the variable wavelength optical transmission circuit 4. The wavelength variable optical transmission circuit 4 can output an optical signal of an arbitrary wavelength selected by the control signal, and can change the wavelength in the wavelength range of λ1 to λn. The wavelength variable optical transmission circuit 4 controls the optical output in accordance with a control signal from the monitoring control circuit 11.

The optical signal output of the optical multiplexer 13 and the optical signal output of the wavelength tunable optical transmission circuit 4 are input to an optical multiplexer 14. The optical multiplexer 14 multiplexes and wavelength-multiplexes these optical signals and outputs them to the transmission line. When the optical multiplexer 13 has wavelength-independent multiplexing characteristics, the optical multiplexers 13 and 14 are integrated,
Wavelength multiplexing can be performed at the same time.

The monitoring control circuit 11 includes optical transmission circuits 1 to 3,
The wavelength tunable optical transmission circuit 4 is connected to the selector 24. The monitoring control circuit 11 collects fault information and controls the optical output for the optical transmission circuits 1 to 3, and sets the optical signal wavelength and controls the optical output for the tunable optical transmission circuit 4. The selector 24 performs signal selection control. The supervisory control circuit 11 specifies a wavelength for which the preliminary switching is to be performed based on the input failure information, and controls switching of the optical transmission circuit.

The operation will be further described. Optical transmission circuit 1
In the normal operation state where no fault has occurred in ~ 3,
The monitoring control circuit 11 outputs a control signal for stopping the optical output to the wavelength tunable optical transmission circuit 4, and the communication is performed by the optical transmission circuit 1.
This is carried out by the optical signals output from .about.3. Here, it is assumed that a failure has occurred in the optical transmission circuit 2 that transmits the optical signal of the wavelength λk. When a failure of the optical transmission circuit 2 is detected by the supervisory control circuit 11, the supervisory control circuit 11 outputs a control signal for selecting the signal of the branch 22 to the selector 24,
, And outputs a control signal to the wavelength tunable optical transmission circuit 4 to set the transmission signal to the wavelength λk and release the optical output stop. This allows
The optical transmission signal of the optical transmission circuit 2 is stopped, and instead, a signal of the wavelength λk is transmitted via the variable wavelength optical transmission circuit 4, and the redundant switching is completed.

After the redundancy switching, the optical transmission circuit 2 in which the fault has occurred is repaired, and the redundancy switching is switched back to return to the normal operation state again. Since the wavelength tunable optical transmission circuit 4 can transmit all wavelengths from λ1 to λn, it operates as a standby circuit even if any of the n optical transmission circuits 1 to 3 fails.

FIG. 4 shows a detailed configuration example of the optical wavelength division multiplexing receiver.

The optical wavelength multiplex signal input from the transmission line is input to the optical demultiplexer 15. The optical splitter 15 splits the input optical signal into two and outputs it. The first output of the optical splitter 15 is connected to the optical splitter 16. The optical demultiplexer 16 splits the input wavelength-division multiplexed optical signal into n signals and outputs the n signals from n output ports. As the optical demultiplexer 16, an optical demultiplexer having n or more output ports independent of wavelength is used. In order to reduce the wavelength selectivity requirement of each output port and the coupling loss between input and output, AWG is used. (Arrayed Waveguid
An optical demultiplexer having wavelength selectivity such as e-grating, an optical filter, or a fiber grating may be used. When the optical demultiplexer 16 has a wavelength-independent branching characteristic, the optical demultiplexers 15 and 16 may be integrated and branched at the same time.

The n outputs of the optical splitter 16 are input to the optical receiving circuits 7 to 9, respectively. Each of the optical receiving circuits 7 to 9 has a unique optical receiving wavelength and receives an optical signal having a wavelength of λ1 to λn. When the optical demultiplexer 16 has a wavelength selection system and a signal of a single wavelength is input, the optical receiving circuits 7 to 9 may use wavelength-independent optical receiving circuits. Further, the fault information of the optical receiving circuits 7 to 9 is sent to the monitoring control circuit 12.

The second output of the optical splitter 15 is connected to the wavelength tunable optical receiving circuit 10. The wavelength variable optical receiving circuit 10 can receive an optical signal of an arbitrary wavelength selected by a control signal from the monitoring control circuit 12, and can change a receiving wavelength in a wavelength range of λ1 to λn. Such a wavelength tunable optical receiving circuit incorporates a wavelength tunable optical filter, and the transmission wavelength of the optical filter is set by a control signal. The wavelength tunable optical receiving circuit 10 receives a signal of a predetermined wavelength by the control signal,
Output.

The branching unit 34 branches the input signal into n signals and outputs the signal. The n selectors 31 to 33 are respectively provided with signals output from the n optical receiving circuits 7 to 9,
Receives one of the n outputs output by the controller, selects one of the signals specified by the control signal from the monitor control circuit 12, and outputs the selected signal to the n main signal processing circuits 35 to 37, respectively. The main signal processing circuits 35 to 37 are circuits that perform separation into low-speed signals and processing of overhead.

The supervisory control circuit 12 includes optical receiving circuits 7 to 9,
The wavelength variable optical receiving circuit 10 is connected to the selectors 31 to 33. The monitoring control circuit 12 collects fault information for the optical receiving circuits 7 to 9, sets the received signal wavelength for the wavelength variable optical receiving circuit 10, and sets the selectors 31 to 9.
For 33, signal selection control is performed. Monitoring control circuit 1
Reference numeral 2 designates a wavelength at which preliminary switching is to be performed based on the fault information input from the optical receiving circuit, and controls switching from the faulty optical receiving circuit to the tunable optical receiving circuit 10.

The operation will be further described. In a normal operation state in which no failure has occurred in the optical receiving circuits 7 to 9, the supervisory control circuit 12 sends signals output from the optical receiving circuits 7 to 9 to the selectors 31 to 33. Is output, and communication is performed by the optical receiving circuits 7 to 9. Here, an optical receiving circuit 8 for receiving an optical signal of wavelength λk
Suppose a failure occurs. When a failure in the optical receiving circuit 8 is detected by the supervisory control circuit 12, the supervisory control circuit 12 outputs a control signal for setting the signal reception wavelength to the wavelength λk to the wavelength variable optical reception circuit 10, and branches to the selector 32. A control signal for selecting the signal of No. 34 is output. Thereby, the signal of the wavelength λk is received via the wavelength variable optical receiving circuit 10 instead of the optical receiving circuit 2, and the redundant switching is completed.

After the redundancy switching, the optical receiving circuit 8 in which the failure has occurred is repaired, and the redundancy switching is switched back to return to the normal operation state again. Wavelength variable optical receiving circuit 10
Can be received for all wavelengths from λ1 to λn, so that it operates as a standby circuit even if any of the n optical receiving circuits 7 to 9 fails.

As described above, for the n wavelengths, the wavelength multiplexing transmitter and the wavelength multiplexing receiver only need to dispose one wavelength-variable backup circuit, and can cope with the fault of any wavelength. An optical wavelength division multiplexing transmission device having a simpler configuration than the conventional one can be realized.

[0034]

As described above, in the present invention, the wavelength multiplexing transmitter and the wavelength multiplexing receiver are provided with the wavelength tunable optical transmitting circuit and the optical receiving circuit, respectively. An optical wavelength division multiplexing transmitter, an optical wavelength division multiplexing receiver, and an optical wavelength division multiplexing transmission apparatus composed of these can be realized, which can cope with a failure and have a simple configuration.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an optical wavelength multiplex transmitter according to the present invention.

FIG. 2 is a basic configuration diagram of an optical wavelength division multiplexing receiver of the present invention.

FIG. 3 is a block diagram showing a configuration example of an optical wavelength multiplex transmitter according to the present invention.

FIG. 4 is a block diagram illustrating a configuration example of an optical wavelength multiplex transmitter according to the present invention.

FIG. 5 is a block diagram of a conventional optical wavelength multiplex transmission device.

[Explanation of symbols]

 1, 2, 3 optical transmitting circuit 4 wavelength variable optical transmitting circuit 5, 13, 14, 47 optical multiplexer 6, 15, 16, 51 optical demultiplexer 7, 8, 9 optical receiving circuit 10 wavelength variable optical receiving circuit 11 , 12 monitoring control circuit 21, 22, 23, 34 branching unit

Claims (7)

[Claims] 1. An optical wavelength division multiplexing transmitter comprising a plurality of optical transmission circuits for transmitting signal lights of specific wavelengths and an optical multiplexer for multiplexing a plurality of signal lights, the wavelength of the signal light to be transmitted is changed. An optical wavelength multiplexing transmitter, comprising: an optical wavelength tunable transmitting circuit capable of controlling the optical wavelength tunable transmitting circuit; 2. A branching unit arranged corresponding to each optical transmission circuit, for branching a main signal into two, and receiving one main signal output from each branching unit by a control signal from a monitoring control circuit. 2. The optical wavelength division multiplexing transmitter according to claim 1, further comprising a selector for selecting one main signal from a plurality of input main signals and transmitting the selected main signal to the variable wavelength optical transmission circuit. 3. An optical transmission method for wavelength-multiplexing and transmitting signal light of a plurality of wavelengths, comprising monitoring a plurality of optical transmission circuits,
When detecting that a failure has occurred in the optical transmission circuit, the function of the optical transmission circuit is stopped, and the signal light having the wavelength transmitted from the optical transmission circuit is transmitted from the variable wavelength optical transmission circuit. Optical transmission method. 4. An optical wavelength division multiplexing receiver comprising an optical demultiplexer for demultiplexing a plurality of signal lights and a plurality of optical receiving circuits for receiving signal lights of specific wavelengths, respectively. An optical wavelength division multiplexing receiver comprising: a variable wavelength optical receiving circuit that can be changed; and a monitoring control circuit that controls the optical receiving circuit and the wavelength variable optical receiving circuit. 5. A branching unit for branching the output of the wavelength tunable optical transmission circuit into a plurality of outputs, and one of an output of the corresponding optical receiving circuit provided for each optical receiving circuit and an output of the branching unit. 5. The optical wavelength division multiplexing transmitter according to claim 4, further comprising: a selector for inputting one of the signals and selecting one of the inputs according to a control signal from a supervisory control circuit and outputting the selected input. 6. An optical receiving method for receiving wavelength-division multiplexed signal light, comprising monitoring a plurality of optical receiving circuits, and stopping the function of the optical receiving circuit when detecting that a failure has occurred in the optical receiving circuit. And transmitting the signal light having the wavelength received by the optical receiving circuit to the wavelength tunable optical receiving circuit. 7. A plurality of optical transmission circuits each for transmitting a signal light of a specific wavelength, an optical multiplexer for multiplexing a plurality of signal lights, and a wavelength variable optical transmission circuit capable of changing the wavelength of the signal light to be transmitted. An optical wavelength division multiplexing transmitter having a supervisory control circuit for controlling the optical transmission circuit and the wavelength tunable optical transmission circuit; an optical demultiplexer for demultiplexing a plurality of signal lights; A plurality of optical receiving circuits, and a wavelength tunable optical transmitting circuit that can change the wavelength of the received signal light,
A wavelength division multiplexing optical transmission device comprising: an optical wavelength division multiplexing receiver having a monitoring control circuit for controlling the optical receiving circuit and the wavelength variable optical receiving circuit.