JPH08298486A - Monitor method for optical repeater and its system - Google Patents

Abstract

PURPOSE: To attain simplicity, miniaturization, commonality and low cost of the equipment configuration and to attain sure monitor control independent of both terminal stations. CONSTITUTION: A terminal station 1 transmits a 1st sub signal modulated by a monitor control signal 10 including address information and control information of the optical repeater 3 while superimposing the sub-signal onto a main signal 5. Information of the optical repeater 3 corresponding to the address among plural optical repeaters is given to a monitor control section 7 of the optical repeater 3, which confirms self-address and generates a response signal 11 including self-alarm information and status information. A 2nd sub signal with a frequency different from that of the 1st sub signal modulated by the signal 11 is superimposed on the main signal 6 and the resulting signal is returned to the terminal station. Thus, the optical repeater is monitored by the use of simple and inexpensive configuration independently of both terminal stations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to monitoring of an optical transmission system including an optical repeater, and more particularly to a method of monitoring and controlling an optical amplification repeater.

[0002]

2. Description of the Related Art Conventionally, as a method of monitoring an optical amplification repeater, a method of allocating sub-signals of different types, for example, different frequencies to each optical amplification repeater is known (Japanese Patent Laid-Open No. 4-160825, first). Conventional example). In this method, the terminal station superimposes the sub-signal assigned to the optical amplification repeater to be monitored and controlled on the main signal and sends it out. The sub signal including this supervisory control signal is transmitted to the all-optical amplification repeater in agreement with the main signal,
The optical amplification repeater to which the corresponding sub-signal is assigned receives the supervisory control signal and sends the response signal back to the terminal station by carrying it on the sub-signal assigned to itself.

On the other hand, unlike the above-mentioned first conventional example, a method is known in which the optical amplification repeater is monitored by one sub-signal (Japanese Patent Laid-Open No. 4-326823, second conventional example). FIG.
Figure 2 shows the system configuration using this method. The optical transmitter 21 superimposes a sub-signal, which is slower and has a smaller amplitude than the main signal 5, on the main signal 5, converts it into an optical signal, and sends it out. This sub-signal is operation command information (monitoring control signal 10) to each optical amplification repeater 19, 20. The content of the operation command is such that a predetermined address code unique to the optical amplification repeater is sequentially transmitted and the monitoring information is transmitted for each optical amplification repeater.
Each of the optical amplification repeaters 19 and 20 detects only the sub-signal from the received signal and demodulates it. When the demodulated signal is addressed to the repeater 20, a response is obtained by coding the information of the optical amplification repeater 20, such as temperature information, amplification degree information, optical output information, and adding the own relay station address if necessary. A sub-signal including the signal 11 is generated. The generated sub signal is converted into an optical signal, combined with the main signal at the output side of the optical amplification repeater 20, and sent to the downstream transmission line. At this time, the optical transmitter 2
1 does not send a sub signal. The optical receiver 22 extracts and demodulates the sub-signal, and detects the optical amplification repeater 20 and detects its monitoring information.

In the second conventional example, since only one type of sub-signal is used, each optical amplification repeater is monitored by the following procedure. On the optical transmitter 21 side, since the sub-signal of the operation command is sent to the optical amplification repeater 20 and then the sub-signal is sent from the optical amplification repeater 20, an appropriate time interval is set so that they do not overlap. After that, the sub signal of the operation command to the next optical repeater is transmitted. The optical amplification repeater 20 does not send the sub signal after sending the response signal 11. Further, the optical amplification repeater 19 which is not called does not, of course, send out the sub signal.

[0005]

In the first conventional optical amplification repeater monitoring method, a different sub-signal is assigned to each optical repeater, so that a sub-station corresponding to the all-optical amplification repeater is assigned at the terminal station. A signal modulation and demodulator is required, and there is a problem that the device scale increases as the number of optical amplification repeaters increases. Further, each optical amplification repeater requires different sub-signal modulators and demodulators, and there is also a problem that all the optical amplification repeaters need to be different.

On the other hand, in the method of the second conventional example, since the monitoring control signal 10 is sent out at regular intervals, the optical amplification repeater 19 is used when the monitoring response time varies depending on the amount of information or for some reason. , 20 delays the transmission of the response signal 11, there is a problem that the sub-signals are duplicated on the optical transmission line and the two cannot be distinguished. Further, in this method, since the operation command and the monitoring information response are made in one direction, the operation command section and the monitoring information receiving section are arranged at different points, and as a result, the relationship between the operation command and the response becomes unclear, There is a problem that the network cannot be managed properly.

The object of the present invention is to solve the above problems,
Optical repeater monitoring method that can simplify, downsize, commonize, and reduce the cost of the device configuration, and that can monitor and control independently from both end stations and can accurately perform network management To provide.

[0008]

In order to achieve the above object, the monitoring method for an optical repeater according to the present invention is a first method modulated from a terminal station by a monitoring control signal including address information and control information of the optical repeater. Of the second sub-signal having a frequency different from that of the first sub-signal modulated by the response signal containing the information of the optical repeater. The signal is superimposed on the main signal and returned to the terminal station.

In order to achieve the above-mentioned object, the monitoring system of the present invention is such that the terminal station has a monitoring control section, a modulation means for modulating the first sub-signal by a monitoring control signal from the monitoring control section, and the sub-control section. A means for superimposing a signal on a main signal, a means for receiving a main signal including a response signal and demodulating the response signal, and an optical repeater receiving a main signal including a supervisory control signal and demodulating the supervisory control signal A supervisory control unit for analyzing the supervisory control signal and generating a response signal including information of the optical repeater; a means for modulating the second sub-signal having a frequency different from the first sub-signal by the response signal; Means for superimposing the second sub-signal on the main signal.

[0010]

In the present invention, the optical repeater is monitored as follows.
First, the supervisory control unit of the terminal station generates a supervisory control signal including address information and control information of the optical repeater, modulates the first sub-signal with this supervisory control signal, and the sub-signal is, for example, a pump laser diode (LD). Is intensity-modulated and superposed on the main signal in the optical fiber amplifier.

Next, in each optical repeater, the main signal is branched and the monitor control signal is demodulated by the demodulator. When the supervisory control unit recognizes that its own address is included in the supervisory control signal, the supervisory control unit generates a response signal including information about the state of the repeater of the self and the alarm information according to the control signal. The response signal modulates a second sub-signal having a frequency different from that of the first sub-signal, and the second sub-signal is intensity-modulated, for example, by a pump laser diode (LD) and superposed on the main signal by an optical fiber amplifier. It After the response signal superimposed on the main signal is returned to the terminal station, the terminal station demodulates the response signal and obtains information of the optical repeater.

Further, since the first sub-signal for supervisory control and the second sub-signal for response have different frequencies, both end stations should independently monitor each optical amplification repeater on the optical transmission line. Therefore, it is possible to accurately grasp the state of the optical transmission line.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram to which the optical repeater monitoring method of the present invention is applied.

In FIG. 1, the terminal station 1 superimposes the first sub-signal modulated by the supervisory control signal 10 on the main signal 5 and sends it out. The supervisory control signal 10 has address information of the optical repeater 3 to be subject to supervisory control and control information for the optical repeater 3. The first sub-signal is slower than the main signal 5 and is minutely intensity-modulated and superimposed on the envelope of the main signal 5. That is, the monitoring control signal 10 becomes a polling signal, and each optical repeater can be monitored and controlled.

The optical repeater 3 demodulates the received sub-signal, and the supervisory control unit detects and analyzes the supervisory control signal. At this time, control is performed according to the control information only when the addresses match, and then the response signal 11 including the status information of itself and the address of itself is generated. At this time, it is possible not to include the own address. The response signal 11 modulates the second sub-signal, and superimposes it on the main signal 6 directed to the terminal station 1 that has transmitted the monitor control signal 10 and outputs the superposed signal. The second sub signal for response at this time is the first sub signal for supervisory control.
Is a signal having a frequency different from that of the sub-signal. At this time,
Since the optical repeater 4 has a different address, it does not generate or return a response signal.

The control contents of the optical repeater include alarm information (temperature abnormality, input deterioration, output deterioration, etc.) and status information (temperature, LD bias, etc.) of the repeater, inventory,
Light output forced stop control etc.

The terminal station 1 receives the response signal 11 and demodulates it to obtain response information about the optical repeater 3 as a response to the transmitted monitor control signal 10. The terminal station 1 can also send the monitor control signal to each optical repeater at a predetermined time interval, but in order to avoid the problems of the second conventional example described above, a series of operations for a certain optical repeater is performed. After the
It is desirable to start operation for the optical amplification repeater at the next address. In the present invention, since the first and second sub-signals different from each other are used, it is possible to distinguish between the supervisory control signal and the response signal corresponding to each sub-signal, and the terminal station 2 also differs from the terminal station 1 if necessary. The same monitoring operation as that of the terminal station 1 can be performed independently.

The terminal station 1 has a timer, and when there is no response, it retries a few times, and when there is no response, an alarm is generated as a communication failure between the optical repeaters which are the target.

Next, the configurations of the terminal station and the repeater will be described with reference to FIG. The terminal station 1 is a well-known terminal station apparatus including an electric / optical (E / O) and optical / electrical (O / E) converters 12 and 13 and a transmitter / receiver 9 including a multiplexer. It has a structure in which the monitoring means of the optical repeater is incorporated. This is to easily add the optical repeater monitoring system to the conventional terminal equipment. The monitor control unit 8 including a CPU or the like generates a monitor control signal including address information and control information of the optical repeater to be monitored as a sub signal at predetermined intervals. The first sub-signal is modulated by the modulator 15. The first sub-signal is superimposed on the envelope of the main signal by minutely modulating the excitation laser of the optical amplifier 14 with the modulated first sub-signal. The electric signal before being input to the E / O converter 12 may be similarly modulated and superimposed on the main signal.

Next, in the optical repeater 3, after the main signal 5 sent from the terminal station 1 is branched by the optical demultiplexer, the light receiving element 17 is provided.
Photoelectric conversion with. The demodulator 16 demodulates a supervisory control signal from the O / E converted electric signal. The monitor control unit 7 composed of a CPU or the like checks the address of the monitor control signal, and if the address is addressed to itself, controls according to the control content of the control signal. Further, the supervisory control circuit 7 generates, as a response signal to the terminal station 1, a second sub-signal in which the information collected according to the control content and its own address (there is no need for its own address) are added. The second sub signal is modulated by the modulator 15. The above-mentioned information includes alarm information and status information of the optical repeater, but information about temperature is obtained by monitoring the temperature of the pump laser of the optical amplifier, and input / output deterioration information is input / output of the optical repeater. Obtained with a power monitor installed at the edge. Next, the modulated second sub-signal slightly intensity-modulates the pump laser of the optical amplifier 14,
It is superimposed on the main signal 6 and returned to the terminal station 1. Terminal 1
Then, the input main signal 6 is branched by the optical demultiplexer and converted into the original electric signal by the light receiving element 17. The demodulator 16 demodulates the second auxiliary signal from the restored electrical signal. The monitoring controller 8 detects the second sub signal as a response signal.

A specific configuration example of the present invention is as follows. The light source of the main signals 5 and 6 in the electrical / optical converter 12 has a wavelength band within the amplification band of the optical amplifier 14, for example, 1.55 μm band in the case of Er-doped fiber optical amplifier and 0.8 in the case of semiconductor optical amplifier. It is possible to apply a light-emitting element in the range from 1 to 1.6 μm. For example, InGaAsP light emitting diode, A
Semiconductor lasers such as 1GaAs type and InGaAsP / InP type can be used. As an optical transmission line, step index fiber, graded index fiber,
There are single fiber (for wavelength 1.31 μm), single mode fiber (for 1.55 μm band) and the like. The modulator 15 can perform intensity modulation, frequency modulation, phase modulation and the like. An ordinary microprocessor can be used as the monitor control unit. As the light receiving element 17, p of Si is used in the 0.8 μm band.
In-PD (photodiode) and Si-APD (avalanche photodiode) can be used. See 1.3
InGaAs-based PD or APD in the μm to 1.5 μm band, Ge-PD (or APD) in the 1.3 μm band
Can be used. As the optical amplifier 14, the Er-doped fiber optical amplifier described above is important, and 0.98 μm as pumping light,
1.48 μm Er-doped fiber optical amplifier is preferred. Besides this, a semiconductor optical amplifier using a multiple quantum well structure or the like can also be used.

FIG. 3 is a diagram for explaining the supervisory control signal 10 and the response signal 11 existing on the transmission line, and only these two waves are superimposed on the transmission line. These can be frequencies that can be transmitted as a sub signal without degrading the characteristics of the main signal in the band from the KHz band to about 10 MHz. If it is higher than this range, it affects the main signal, and if it is lower than this range, necessary information cannot be captured. In addition, although it is necessary to use different frequencies, it is necessary to provide a difference (for example, 10 KHz or more) that does not deteriorate communication between them.

The present invention is mainly directed to a two-way communication system,
For example, the description is made assuming the application to the backbone transmission system on land / sea, but the application to the optical subscriber system is also easy. That is, this is executed by sending a supervisory signal from the center station to the optical amplification repeater on each branch line by polling, and returning a response signal on the upstream dedicated route or in the same fiber.

[0024]

As described above, according to the present invention, the first and second sub-signals having different frequencies are used for the supervisory control signal from the terminal station and the response signal from the optical repeater. It is possible to monitor and control the transmission path including the optical amplification repeater without being aware of it. Moreover, since only two waves are used as the sub-signals, there is an effect that simplification, downsizing, commonization, and cost reduction of the device can be realized. Further, since it is the polling method, there is an effect that the transmission line management including the monitoring, control, and communication at the terminal station can be appropriately performed.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing a signal waveform on a transmission line used in the present invention.

FIG. 4 is a system configuration diagram showing a conventional example.

[Explanation of symbols]

 1, 2 Terminal station 3, 4 Optical repeater 5, 6 Main signal 7, 8 Monitoring control unit 9 Multiplex conversion unit 10 Monitoring control signal 11 Response signal 12 Electrical / optical converter 13 Optical / electrical converter 14 Optical amplifier 15 Modulation Device 16 Demodulator 17 Light receiving element 19, 20 Optical amplification repeater 21 Optical transmitter 22 Optical receiver

Claims (10)

[Claims] 1. A method of monitoring an optical repeater in an optical repeater transmission system including a terminal station, an optical transmission line, and an optical repeater, wherein the terminal station includes a supervisory control signal including address information and control information of the optical repeater. A transmitting step of superimposing and transmitting the first sub-signal modulated by the optical signal on the main signal, and the optical sub-repeater corresponding to the address being modulated by the response signal including the information of the optical sub-repeater. And a return step of superimposing a second sub-signal having a frequency different from that of the signal on the main signal and returning the main signal to the terminal station. 2. The transmitting step is started for an optical repeater different from the optical repeater after receiving the information of the optical repeater after the terminal station first transmits the supervisory control signal. A monitoring method of the optical repeater described. 3. The method of monitoring an optical repeater according to claim 1, wherein the response signal of the optical repeater in the returning step includes address information of the optical repeater. 4. A monitoring system of an optical repeater in an optical repeater transmission system including a terminal station, an optical transmission line, and an optical repeater, wherein the terminal station is provided with a supervisory control unit and a supervisory control signal from the supervisory control unit. The optical repeater is provided with: a modulation unit that modulates the first sub-signal, a unit that superimposes the first sub-signal on the main signal, and a unit that receives the main signal including the response signal and demodulates the response signal. Means for receiving a main signal including a supervisory control signal and demodulating the supervisory control signal, a supervisory control unit for analyzing the supervisory control signal and generating a response signal including information of the optical repeater, and the first signal by the response signal. A monitoring system for an optical repeater, comprising: a means for modulating a second sub-signal having a frequency different from that of the sub-signal, and a means for superimposing the second sub-signal on the main signal. 5. The monitoring system for the optical repeater according to claim 4, wherein the terminal station includes an optical amplifier. 6. The monitoring system for an optical repeater according to claim 4, wherein the means for superimposing the sub signal on the main signal is an optical amplifier. 7. The monitoring system for an optical repeater according to claim 4, wherein the means for superimposing the sub signal on the main signal in the terminal station is an electro-optical converter. 8. The optical repeater comprises an optical amplifier, a demodulating means and a modulating means for two directions, respectively.
The optical repeater monitoring system according to 5, 6, or 7. 9. The optical amplifier is an optical fiber amplifier or a semiconductor optical amplifier, as set forth in claim 4.
The optical repeater monitoring system described. 10. The light according to claim 1, wherein the frequencies of the first and second sub-signals are in the range from KHz band to approximately 10 MHz band. Repeater monitoring system.