JPH08288910A - Optical amplifier repeater - Google Patents

Abstract

PURPOSE: To provide the optical amplifier repeater in which an optical signal with a monitor control signal superimposed thereon is relayed independently of a low frequency characteristic of a subcarrier frequency of a circuit for optical amplification. CONSTITUTION: The optical amplification repeater is configured such that an optical identification reproduction circuit 12 eliminating a monitor control signal component from an optical signal amplitude-modulated depending on the monitor control signal is provided to a pre-stage of an EDF(erbium doped optical fiber) 14. When a monitor control signal detection circuit 15 discriminates the monitor control signal superimposed on the optical signal to be addressed to other repeater, a stimulate LD control circuit 18 controlling a stimulated optical level of a stimulated LD applies amplitude-modulation in response to the monitor control signal to the optical signal outputted from the EDF 14. When the circuit 15 discriminates it that the monitor control signal is addressed to its own repeater, the control circuit 18 applies the amplitude modulation to the optical signal in response to a reply signal from a reply signal generating circuit 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical amplifier repeater, and in particular, information for monitoring or controlling the device,
The present invention relates to an optical amplification repeater used in an optical communication system that is notified by amplitude-modulating an optical signal.

[0002]

2. Description of the Related Art In an optical communication system using an optical amplification repeater, a supervisory control signal for monitoring or controlling the operating state of the optical amplification repeater and an optical signal to be transmitted between terminal stations are monitored and controlled. By amplitude modulation according to the signal,
There is a system in which a terminal station notifies an optical amplification repeater.

Such an optical communication system is, for example,
It is described in JP-A-5-199184. The optical amplification repeater described in this publication is used by being connected to a pair of optical transmission lines, and is configured to operate as follows.

In this optical amplification repeater, a part of the optical signal input from each optical transmission line is converted into an electric signal and a predetermined frequency component contained in the electric signal, that is, a supervisory control signal component is extracted. The remaining optical signals are directly amplified by the optical amplifier and sent out on the transmission path. And
The optical amplification repeater judges, based on the content of the extracted supervisory control signal, whether or not the supervisory control signal is for its own apparatus, and if it is for its own apparatus, it responds to the content. While performing monitoring or control, the optical signal propagating on the optical transmission line on the side different from the optical transmission line on which the monitoring control signal is propagated is subjected to amplitude modulation according to the monitoring result or control result. .

[0005]

In the optical communication system in which the optical amplification repeater is combined as described above, when the optical signal input to a certain optical amplification repeater does not include the supervisory control signal for the own device, The optical signal is amplified in the optical amplification repeater and transmitted to the next optical amplification repeater. That is, in an optical communication system using a conventional optical amplification repeater, the number of optical signals including the supervisory control signal is increased by the time the supervisory control signal is actually transmitted to the optical amplification repeater subject to supervisory control. It will be amplified by the optical amplification repeater.

Therefore, in the case of constructing an optical communication system by combining the conventional optical amplification repeaters, each supervisory control signal is identified so that the supervisory control signal can be identified even when it is amplified by a plurality of optical amplification repeaters. There has been a problem that the interval for installing the optical amplification repeater must be set in consideration of the low frequency characteristic of the subcarrier frequency of the optical amplification repeater (optical amplifier).

Therefore, an object of the present invention is to provide an optical amplification repeater capable of repeating an optical signal on which a supervisory control signal is superimposed without depending on the low frequency characteristic of the subcarrier frequency of a circuit for performing optical amplification. Especially.

[0008]

According to a first aspect of the invention, (a) an optical signal amplitude-modulated according to a supervisory control signal which is information for instructing supervisory content and control content is input. Optical branching means for branching and outputting the input optical signal, (b) photoelectric conversion means for converting one optical signal branched by the optical branching means into an electrical signal, and (c) branching by the optical branching means. A supervisory control signal component removing means for outputting an optical signal from which the supervisory control signal component has been removed from the other optical signal thus generated; and (d) an optical amplifying means for amplifying the output of the supervisory control signal component removing means as light. (E) Judging means for identifying the content of the supervisory control signal superimposed on the optical signal based on the electric signal output from the photoelectric conversion means, and determining whether or not the supervisory control signal is for the device itself When,
(F) monitoring control means for executing monitoring or control according to the content of the monitor control signal when the determining means determines that the monitor control signal is for the device itself;
(G) When the judging means judges that the supervisory control signal is not for the device itself, the optical amplification is performed so that the amplitude modulation according to the discrimination result of the judging means is applied to the optical signal output from the optical amplifying means. Gain control means for controlling the gain of the means.

That is, according to the first aspect of the present invention, when the supervisory control signal is once removed from the optical signal amplitude-modulated according to the supervisory control signal and the supervisory control signal is for another device, Configures the optical amplification repeater so that when the optical signal from which the supervisory control signal component is removed is amplified, the optical signal is again subjected to amplitude modulation according to the supervisory control signal.

A combination of a rare-earth-doped optical fiber such as an erbium-doped optical fiber and a pumping light source can be used as the optical amplifying means, and the gain control means can control the level of pumping light generated by the pumping light source. It is possible to use a device that controls the gain by controlling, and when an erbium-doped optical fiber is used, it is possible to construct an optical communication system using the low loss wavelength region of the optical fiber. Further, as the monitoring control signal component removing means,
An optical identification / reproduction circuit for identifying / reproducing an optical signal as light can be used.

According to a second aspect of the present invention, (a) the inputted optical signal is inputted with an optical signal amplitude-modulated according to a supervisory control signal which is information for instructing the supervisory content and control content. Optical branching means for branching and outputting, (b) photoelectric conversion means for converting one optical signal branched by the optical branching means into an electric signal, and (c) other optical signal branched by the optical branching means. Monitoring control signal component removing means for outputting an optical signal from which the monitoring control signal component is removed, (d) optical amplifying means for amplifying the output of the monitoring control signal component removing means as light, and (e) photoelectric conversion means. Based on the electrical signal output by the device, the content of the supervisory control signal superimposed on the optical signal is identified, and the determination means for determining whether the supervisory control signal is for the device itself, The judgment means is the supervisory control signal When it is determined that the monitoring control signal corresponds to the monitoring control signal, the monitoring control unit that performs monitoring or control according to the content of the monitoring control signal, and generates a response signal indicating the monitoring result or the content of the control result, and (g) Judgment When the means determines that the supervisory control signal is not for its own device, the gain of the optical amplifying means is adjusted so that the amplitude modulation according to the identification result of the determining means is applied to the optical signal output from the optical amplifying means. If it is determined that the monitoring control signal is for the device itself, the optical signal output from the optical amplifying means is amplitude-modulated according to the response signal generated by the monitoring control means. And gain control means for controlling the gain of the optical amplification means.

That is, according to the second aspect of the invention, when the supervisory control signal is once removed from the optical signal amplitude-modulated according to the supervisory control signal and the supervisory control signal is for another device, When the optical signal from which the supervisory control signal component has been removed is amplified, the optical signal is again subjected to amplitude modulation according to the supervisory control signal, and when the supervisory control signal is for the device itself, the supervisory control signal The optical amplification repeater is configured so that amplitude amplification according to a response signal to the supervisory control signal is performed when the optical signal from which the component is removed is amplified.

A combination of a rare earth-doped optical fiber such as an erbium-doped optical fiber and a pumping light source can be used as the optical amplifying means, and the gain controlling means can control the level of the pumping light generated by the pumping light source. It is possible to use a device that controls the gain by controlling, and when an erbium-doped optical fiber is used, it is possible to construct an optical communication system using the low loss wavelength region of the optical fiber. Further, as the monitoring control signal component removing means,
An optical identification / reproduction circuit for identifying / reproducing an optical signal as light can be used.

[0014]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows the configuration of an optical amplification repeater according to an embodiment of the present invention. As shown in the figure, the optical amplification repeater of the embodiment has an optical branching circuit 11, an optical discriminating and reproducing circuit 12, an optical coupling circuit 13, and an EDF (erbium-doped optical fiber).
14, monitoring control signal detection circuit 15, and monitored control circuit 16
It includes a response signal generation circuit 17, an excitation LD (LASER Diode) control circuit 18, and an excitation LD (LASER Diode) 19.

The optical signal relayed by the optical amplification repeater of the embodiment is an optical signal subjected to amplitude modulation according to information for monitoring and controlling the device (hereinafter referred to as a supervisory control signal). The optical signal input from the optical input terminal 21 is branched by the optical branching circuit 11 and supplied to the optical identification and reproduction circuit 12 and the monitor control signal detection circuit 15.

The optical discriminating / reproducing circuit 12 discriminates and reproduces the inputted optical signal as it is, thereby removing the supervisory control signal component from the inputted optical signal, that is, an optical signal having a constant amplitude. It is a circuit that outputs a signal. The optical signal from the optical discriminating and reproducing circuit 12 is wavelength-multiplexed with the pumping light from the pumping LD 19 in the optical coupling circuit 13,
14 and is amplified by the EDF 14 in accordance with the level of the pumping light from the pumping LD 19 to obtain the optical output terminal 2
It is output from 2.

The supervisory control signal detection circuit 15 converts the input optical signal into an electrical signal, extracts a signal of a predetermined frequency component (frequency component corresponding to the supervisory control signal) from the electrical signal, and extracts the signal. Based on the signal, it is determined whether the supervisory control signal superimposed on the input optical signal is for the device itself, and when it is determined that the supervisory control signal is for the device itself. Notifies the monitored control circuit 16 of the content thereof, reproduces the extracted signal and supplies the reproduced signal to the excitation LD control circuit 18 when it judges that the monitor control signal is not for its own device. Circuit, which is configured by combining a photodiode, a bandpass filter, and the like.

The monitored / controlled circuit 16 is a circuit that actually executes monitoring and control of each circuit in the optical amplification repeater, and executes monitoring or control according to the notification contents from the monitoring control signal detection circuit 15. , The monitoring result, etc. are notified to the response signal generating circuit 17. The response signal generation circuit 17 generates a response signal according to the notification content from the monitored control circuit 16 according to a predetermined procedure, and outputs it to the excitation LD control circuit 18.

The response signal and the supervisory control signal are signals in the same frequency band, and the supervisory control detection circuit 15 described above, when the information superimposed on the optical signal is the response signal, The same process as the process for the supervisory control signal not for the own device is performed.

The pump LD control circuit 18 then pumps the pump L
The pumping LD 19 is controlled so that the pumping light level output from D 19 corresponds to the signal input from one of the monitoring control signal detecting circuit 15 and the response signal generating circuit 17.
Control.

In the optical amplification repeater of the embodiment configured as described above, the supervisory control signal is once removed from the optical signal amplitude-modulated according to the supervisory control signal, and the supervisory control signal is automatically transmitted. In the case of a device, when the optical signal from which the supervisory control signal component has been removed is amplified, amplitude modulation according to the response signal to the supervisory control signal is performed. Then, when the supervisory control signal is for another device, the amplitude modulation according to the supervisory control signal is newly performed when the optical signal from which the supervisory control signal component has been removed is amplified.

Therefore, in the optical amplification repeater of the embodiment,
This means that the supervisory control signal can be transmitted to the next optical repeater without depending on the low-frequency pass characteristic of the subcarrier frequency of the optical amplifier (EDF + pumping LD).

In the optical amplification repeater of the embodiment, the response signal is sent out on the optical transmission line on which the supervisory control signal has been transmitted. When configured as a device that performs relaying, a response signal may be superimposed on an optical signal on an optical transmission line different from the optical transmission line on which the supervisory control signal has been transmitted. Further, in the optical amplification repeater of the embodiment, the EDF is used to amplify the optical signal.
It goes without saying that the optical amplification repeater may be configured by using another rare earth-doped optical fiber or an optical direct amplifier such as a semiconductor laser amplifier.

[0025]

As described above, according to the present invention,
If the input optical signal contains a supervisory control signal that is not related to the device itself, the optical signal that has been returned to a constant amplitude is output again after being subjected to amplitude modulation according to the supervisory control signal. Therefore, the relay distance (transmission distance) does not depend on the low frequency pass characteristic of the subcarrier frequency of the optical amplifying means.

Further, as in the invention described in claim 2, even if the response signal is generated in response to the supervisory control signal,
In an optical communication system configured by using this optical amplification repeater, when an optical signal in which a response signal is superimposed is input to each optical amplification repeater, the response signal component is removed from the optical signal and a constant amplitude and Since the amplitude signal is again modulated by the regenerated response signal, the relay distance of the optical amplification repeater may be limited due to the limitation of the transmission distance of the response signal. It will not happen.

When an erbium-doped optical fiber is used as the optical amplifying means as in the fourth aspect of the invention, the low loss wavelength region of the optical fiber as the transmission line can be utilized. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical amplification repeater according to an embodiment of the present invention.

[Explanation of symbols]

 11 Optical Branch Circuit 12 Optical Discrimination / Regeneration Circuit 13 Optical Coupling Circuit 14 Erbium Doped Optical Fiber (EDF) 15 Monitoring Control Signal Detection Circuit 16 Monitored Control Circuit 17 Response Signal Generation Circuit 18 Excitation LD Control Circuit 19 Excitation LD 21 Optical Input Terminal 22 Optical output terminal

Claims (5)

[Claims] 1. Optical branching means for inputting an optical signal amplitude-modulated according to a supervisory control signal, which is information for instructing monitoring content or control content, and branching and outputting the input optical signal. A photoelectric conversion means for converting one optical signal branched by the optical branching means into an electric signal, and an optical signal obtained by removing the supervisory control signal component from the other optical signal branched by the optical branching means. A supervisory control signal component removing means, an optical amplifying means for amplifying the output of the supervisory control signal component removing means as light, and a monitor superposed on the optical signal based on an electric signal output by the photoelectric converting means. Determination means for identifying the content of the control signal and determining whether or not the monitoring control signal is for its own device; and when this determining means determines that the monitoring control signal is for its own device, A monitoring control unit that performs monitoring or control according to the content of the monitoring control signal, and an amplitude according to the identification result of the determination unit when the determination unit determines that the monitoring control signal is not for its own device. An optical amplification repeater comprising: a gain control unit that controls the gain of the optical amplification unit so that the optical signal output from the optical amplification unit is modulated. 2. An optical branching unit for inputting an optical signal amplitude-modulated according to a supervisory control signal, which is information for instructing monitoring content or control content, and for branching and outputting the input optical signal. A photoelectric conversion means for converting one optical signal branched by the optical branching means into an electric signal, and an optical signal obtained by removing the supervisory control signal component from the other optical signal branched by the optical branching means. A supervisory control signal component removing means, an optical amplifying means for amplifying the output of the supervisory control signal component removing means as light, and a monitor superposed on the optical signal based on an electric signal output by the photoelectric converting means. Determination means for identifying the content of the control signal and determining whether or not the monitoring control signal is for its own device; and when this determining means determines that the monitoring control signal is for its own device, A monitoring control unit that performs monitoring or control according to the content of the monitoring control signal and that generates a response signal indicating the content of the monitoring result or the control result; When it is determined that the optical signal is output, the gain of the optical amplification unit is controlled so that the optical signal output from the optical amplification unit is amplitude-modulated according to the identification result of the determination unit. If it is determined that
Gain control means for controlling the gain of the optical amplification means so that amplitude modulation according to the response signal generated by the monitoring control means is applied to the optical signal output from the optical amplification means. Optical amplification repeater. 3. The optical amplification means is a combination of a rare earth-doped optical fiber and a pumping light source, and the gain control means controls the gain by controlling the level of the pumping light generated by the pumping light source. The optical amplification repeater according to claim 1 or 2, wherein 4. The optical amplification repeater according to claim 3, wherein the rare earth-doped optical fiber provided in the optical amplification means is an erbium-doped optical fiber. 5. The optical amplifier according to claim 1, wherein the supervisory control signal component removing means uses an optical discriminating and reproducing circuit for discriminating and reproducing an optical signal as light. Relay device.