JP2001186091A - Optical transmission system - Google Patents

Abstract

(57) [Problem] To provide an optical transmission system capable of transmitting an accurate number of optical signals to an optical amplifier even if the optical signal is interrupted due to a human error or the like. A plurality of optical transmitters that output optical signals having different wavelengths from each other, an optical multiplexer that multiplexes optical signals output from the optical transmitters and outputs the multiplexed optical signals,
The optical amplifier 3 includes an optical amplifier 3 for amplifying the multiplexed optical signal output from the optical multiplexer 2 and an optical signal number detector 7 for detecting the number of optical signals currently output from the optical transmitter 1. Is an optical transmission system controlled based on the number of optical signals detected by the number-of-optical-signals detection unit 7, wherein a plurality of optical transmitters 1 and a plurality of optical multiplexers 2 are connected. Optical connector 10 is provided,
Detects the number of optical signals based on each optical signal transmitted between the optical connector 10 and the optical multiplexer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission system, and more particularly, to an optical transmission system that multiplexes optical signals having a plurality of wavelengths different from each other, amplifies and outputs the multiplexed optical signal.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a configuration of a general wavelength division multiplexing optical transmission system. As shown in FIG.
The wavelength division multiplexing optical transmission system includes a plurality of (six in the example of FIG. 2) optical transmitters 1 for transmitting optical signals of a plurality of different wavelengths, and an optical signal of a plurality of channels transmitted from the optical transmitter 1. An optical multiplexer 2 for wavelength multiplexing, a plurality of optical amplifiers 3 connected in a plurality of stages for amplifying and relaying the multiplexed optical signal wavelength-multiplexed by the optical multiplexer 2, and amplification by the optical amplifier 3 An optical demultiplexer 4 for wavelength-demultiplexing the separated optical signal for each channel, and an optical receiver 5 for receiving each optical signal wavelength-separated by the optical demultiplexer 4 are provided.

The optical amplifier 3 detects the number of wavelengths of an optical signal and controls the output level according to the received level.

[0004] As a prior art for that purpose, for example, the invention disclosed in Japanese Patent Application Laid-Open No. 9-274206 is known. FIG. 3 is a block diagram showing a configuration of a conventional optical transmission system. As shown in FIG. 3, the conventional optical transmission system comprises a plurality (two in FIG. 3) of optical transmitters 1 for transmitting optical signals of different wavelengths, an optical multiplexer 2 for wavelength-multiplexing the optical signals, An optical amplifier 3 that directly amplifies the multiplexed optical signal and outputs an amplified multiplexed optical signal, and a part of the optical signal of each wavelength is split by an optical splitter 6 based on the split optical signal. An optical signal number detector 7 for detecting the number of optical signals currently being transmitted. The optical amplifier 3 receives the number of optical signals detected by the optical signal number
And an optical amplification control circuit for controlling the output of the optical amplifier. The optical amplifier 3 includes a rare earth element-doped fiber and a pumping light source that supplies pumping light thereto, and the optical amplification control circuit includes a pumping light control circuit that controls the intensity of the pumping light according to the number of optical signals. The pumping light control circuit sets an injection current to the pumping light source so that a predetermined intensity of the amplified optical signal is obtained according to the number of optical signals.

According to the conventional optical transmission system, even when one or two or more optical signals are interrupted, the output of the optical amplifier 3 is controlled in accordance with the number of input optical signals, whereby The output of the optical amplifier 3 for each optical signal of each wavelength can be made constant regardless of the state of other wavelengths.

[0006]

However, in the conventional optical transmission system, when the optical transmitter 1 and the optical splitter 6 are integrally formed, the optical splitter 6 and the optical multiplexer 2 are not connected to each other. If the optical signal is interrupted in the transmission path between the optical amplifiers 3, the number of optical signals detected by the optical signal number detector 7 does not match the number of optical signals actually input to the optical amplifier 3. The optical amplifier 3 is driven by the parameter, and a desired optical output cannot be obtained.

As one of the causes of the interruption of the optical signal, there is a possibility that the optical connector 8 connecting the optical splitter 6 and the optical multiplexer 2 is detached due to a human error. Particularly, in the wavelength division multiplexing optical transmission system, the number of channels may be increased or decreased during operation. At that time, the optical connector 8 that should not be removed may be accidentally removed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is capable of transmitting an accurate number of optical signals to an optical amplifier even if the optical signal is interrupted due to a human error or the like. The purpose is to provide a system.

[0009]

An optical transmission system according to the present invention comprises a plurality of optical transmitters for outputting optical signals having mutually different wavelengths, and multiplexes the optical signals output from the optical transmitters by multiplexing them. An optical multiplexer that outputs a multiplexed optical signal, and an optical amplifier that amplifies the multiplexed optical signal output from the optical multiplexer.
An optical signal number detection unit for detecting the number of optical signals currently output from the optical transmitter, the optical output level from the optical amplifier, the number of optical signals detected by the optical signal number detection unit An optical transmission system controlled on the basis of a plurality of optical connectors for respectively connecting the plurality of optical transmitters and the optical multiplexer, wherein the optical signal number detection unit includes the optical connector and the optical multiplexer. The number of optical signals is detected based on each optical signal transmitted between the devices.

The optical signal number detector includes a plurality of optical splitters for splitting a part of each optical signal transmitted between the optical connector and the optical multiplexer, and a splitter for the plurality of optical splitters. An optical receiving unit that receives the optical signal, and detects the number of optical signals from the number of received optical signals in the optical receiving unit, at least the optical multiplexer and the plurality of optical splitters are integrated. Is preferred.

According to the present invention, a plurality of optical connectors are provided for connecting a plurality of optical transmitters and an optical multiplexer, respectively.
The optical signal number detector detects the number of optical signals based on each optical signal transmitted between the optical connector and the optical multiplexer. Even in the case where the optical signal is output, the optical signal output from the corresponding optical transmitter is not input to the optical signal number detecting unit, so the optical signal number detecting unit detects the accurate optical signal number and transmits it to the optical amplifier. be able to.

[0012]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the optical transmission system of the present invention.

As shown in FIG. 1, an optical transmission system according to an embodiment of the present invention includes a plurality (two in FIG. 1) of optical transmitters 1 for outputting optical signals having different wavelengths, and an optical transmitter. An optical multiplexer 2 for multiplexing the optical signals output from the optical signal 1 and outputting the multiplexed optical signal, an optical amplifier 3 for amplifying the multiplexed optical signal output from the optical multiplexer 2, and an optical transmitter 1
And an optical signal number detecting unit 7 for detecting the number of optical signals output from the optical disc.

The optical signal number detector 7 includes a plurality of optical splitters 6 for branching a part of each optical signal transmitted between the optical transmitter 1 and the optical multiplexer 2, and a plurality of optical splitters. And an optical receiving unit 9 for receiving the optical signal split by the unit 6 and detecting the number of optical signals from the number of received optical signals.

The optical receiving unit 9 includes a photodiode 9a for performing optical / electrical conversion of the optical signal output from each optical splitter 6,
A counter 9b for receiving the electrical signal converted by the photodiode 9a and calculating the number of optical signals outputting light intensity equal to or higher than a predetermined value. Information on the number of optical signals calculated by the counter 9b is sent to the optical amplifier 3, and the gain of the optical amplifier 3 is controlled so that an optical output corresponding to the number of optical signals is obtained.

The optical splitter 6, the optical multiplexer 2, and the optical receiver 9 are integrated as one device. Also,
A plurality of first optical connectors 10 are provided for connecting the plurality of optical transmitters 1 and the optical multiplexer 2, and a second optical connector 11 is provided for connecting the optical multiplexer 2 and the optical amplifier 3. Is provided. As a specific example of integration, these components are mounted on one board or are housed in one housing. According to such a configuration, there is no need to interpose an optical connector between the optical splitter 6 and the optical multiplexer 2.

When the optical signals output from the plurality of optical transmitters 1 are normally input to the optical amplifier 3, the optical amplifier 3 operates according to the number of optical signals detected by the optical signal number detector 7. Gain is controlled.

Further, an optical splitter 6 is provided between the optical connector 10 and the optical multiplexer 2, and the number of optical signals is counted based on the presence or absence of an optical signal transmitted between the optical connector 10 and the optical multiplexer 2. Even if the first optical connector 10 is detached due to a human error and the optical signal is interrupted, the optical signal output from the corresponding optical transmitter 1 is not input to the optical signal number detecting unit 7. . Therefore, the optical signal number detection unit 7 can detect the accurate number of optical signals included in the multiplexed optical signal output from the optical multiplexer 2 and transmit it to the optical amplifier 3.

If the second optical connector 11 is removed due to a human error or the like, the wrong number of optical signals is transmitted to the optical amplifier 3. In this case, all the optical signals are already transmitted. Since transmission of optical signals becomes impossible,
Treated as a transmission failure.

As shown in FIG. 2, when the optical amplifiers 3 are connected in multiple stages, the optical signal number detector 7 transmits the optical signal number information to all the optical amplifiers 3.

The present invention is not limited to the above embodiment, and various changes can be made within the technical scope described in the claims.

In the embodiment of the present invention, it is sufficient that at least the optical multiplexer 2 and the plurality of optical splitters 6 are integrated, and the optical receiver 9 may not be integrated. When integrated, it is possible to prevent the optical connector from coming off at this portion, which is preferable. Further, the optical splitter 6, the optical multiplexer 2, the optical receiver 9, and the optical amplifier 3 may be integrated as one device. In this case, since the second optical connector 11 becomes unnecessary, it is possible to prevent the above-described transmission failure from occurring.

Further, the present invention can be applied not only to the wavelength multiplexing optical transmission system but also to other multiplexing type optical transmission systems such as a frequency multiplexing optical transmission system.

[0024]

According to the present invention, a plurality of optical connectors are provided for connecting a plurality of optical transmitters and an optical multiplexer, respectively, and the number of optical signal detectors is provided between the optical connector and the optical multiplexer. Since the number of optical signals is detected based on each transmitted optical signal, even if the optical connector is disconnected due to a human error or the like and the optical signal is interrupted, the signal is output from the corresponding optical transmitter. Since the optical signal is not input to the optical signal number detecting section, the optical signal number detecting section can detect the accurate optical signal number and transmit it to the optical amplifier. As a result, a highly reliable optical transmission system can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical transmission system according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a general wavelength multiplexing optical transmission system.

FIG. 3 is a block diagram illustrating a configuration of a conventional optical transmission system.

[Explanation of symbols]

 1: optical transmitter 2: optical multiplexer 3: optical amplifier 4: optical demultiplexer 5: optical receiver 6: optical splitter 7: optical signal number detector 8: optical connector 9: optical receiver 9a: photodiode 9b: counter 10: first optical connector 11: second optical connector

Claims (2)

[Claims] A plurality of optical transmitters for outputting optical signals having different wavelengths from each other; an optical multiplexer for multiplexing optical signals output from the optical transmitters and outputting as a multiplexed optical signal; An optical amplifier that amplifies the multiplexed optical signal output from the optical multiplexer; and an optical signal number detector that detects the number of optical signals currently output from the optical transmitter; The output level is an optical transmission system controlled based on the number of optical signals detected by the optical signal number detection unit, wherein a plurality of optical connectors respectively connecting the plurality of optical transmitters and the optical multiplexer are provided. The optical transmission system provided, wherein the optical signal number detection unit detects the number of optical signals based on each optical signal transmitted between the optical connector and the optical multiplexer. 2. The optical signal number detecting section comprises: a plurality of optical splitters for splitting a part of each optical signal transmitted between the optical connector and the optical multiplexer; and a plurality of optical splitters. An optical receiving unit that receives the optical signal branched by the optical receiving unit, and detects the number of optical signals from the number of received optical signals in the optical receiving unit; at least the optical multiplexer and the plurality of optical splitters are integrated with each other. The optical transmission system according to claim 1, wherein the optical transmission system is integrated.