JPH0522234A - Monitor system for optical amplifier repeater - Google Patents

Abstract

PURPOSE:To collect information in the repeater from each optical amplifier repeater without giving deterioration in the transmission characteristic of a main signal. CONSTITUTION:An optical transmitter designates sequentially an optical amplifier repeater from which information in a repeater is to be sent by sending a 1st sub signal. The designated optical amplifier repeater uses a 2nd sub signal whose content is in-repeater information to modulate a semiconductor amplifier 119 and superimposes the 2nd sub signal onto a main signal being an input signal light and outputs the result. An optical receiver extracts the 2nd sub signal from each optical amplifier repeater to obtain its in-repeater information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring system for an optical amplification repeater using an optical amplifier in an optical transmission system.

[0002]

2. Description of the Related Art Conventionally, this type of monitoring system assigns subcarriers of different frequencies to each optical amplification repeater, and each optical amplification repeater independently assigns the information in the repeater of its own station. The carrier was used to send to the optical receiver.

FIG. 2 is a block diagram showing an example of the optical amplification repeater. In FIG. 2, the information in the optical repeater to be monitored, such as the current, temperature, amplified output power, and amplification degree of the semiconductor optical amplification element 207, is converted into a digital electric signal by the electric signal conversion circuit 212, and the sub information by the FSK modulation circuit 213. Carrier wave FS
In the K-modulated form, the drive current to the semiconductor optical amplification element 207 is modulated by the amplitude modulation circuit 214 and propagated through the transmission fiber 211 together with the main signal.

FIG. 3 is a block diagram showing an example of the optical receiver. In FIG. 3, the bandpass filters 220, 222, 2
Reference numeral 24 is tuned to the subcarrier of each optical amplification repeater, and the FSK demodulators 221, 223, and 225 following these are demodulated and output the in-repeater information of each optical amplification repeater. As a result, the operating state of each optical amplification repeater can be centrally monitored on the optical receiver side.

[0005]

However, in the above-mentioned monitoring method, the problem that the degree of deterioration of the transmission characteristics of the main signal due to the subcarrier increases as the number of stages of the optical amplification repeater increases, and the optical reception In the machine, there is a problem in that as many bandpass filters and FSK demodulators as the number of optical amplification repeaters are required.

The present invention has been made to solve the above-mentioned problems, and even if the number of stages of the optical amplification repeater is increased, the deterioration of the transmission characteristics of the main signal due to the subcarrier is not increased, and An object of the present invention is to provide an optical amplification repeater monitoring method in which the number of subcarrier demodulation circuits in an optical receiver does not increase due to the number of optical amplification repeaters.

[0007]

In order to achieve the above object, the present invention provides an optical amplification repeater in an optical transmission system for transmitting an output signal light of an optical transmitter to an optical receiver through a plurality of transmission fibers and an optical amplification repeater. In the monitoring system of the optical amplifier, the optical transmitter includes means for superimposing a first sub-signal designating an optical amplification repeater on a main signal, converting the signal into signal light, and transmitting the signal light to a transmission fiber. When the first sub-signal detected from the input signal light designates its own station, it is a second sub-signal containing the information in the repeater, and supplies the drive current to the semiconductor optical amplifier for amplifying the input signal light. The second by modulating
Means for superimposing the sub-signal of 1) on the main signal of the input signal light and sending it to the transmission fiber, and the optical receiver detects the second sub-signal from the input signal light and outputs the in-repeater information. It is equipped with.

[0008]

By transmitting the first sub-signal, the optical transmitter sequentially designates the optical amplification repeaters to which the intra-repeater information should be sent, one station at a time.

The designated optical amplification repeater transmits the second sub-signal by modulating the semiconductor optical amplifier that amplifies the input signal light with the second sub-signal containing the information in the repeater. .. At this time, since the other optical amplification repeaters do not send the second sub-signal, the transmission characteristics of the main signal are not deteriorated by the presence of the plurality of second sub-signals. The frequency of the second sub-signal is common to each optical amplification repeater.

The optical receiver extracts the second sub-signal from each optical amplification repeater by using one low-pass filter and the sub-signal demodulation circuit to obtain the repeater information.

[0011]

FIG. 4 is a system configuration diagram showing an embodiment of the present invention. In FIG. 4, 101 is an optical amplification repeater, 102
Is an optical transmitter, 103 is an optical receiver, 104 is a transmission fiber, and each optical amplification repeater 101 is a transmission fiber 104.
The optical signal from the side of the optical transmitter 102, which has been attenuated by, is amplified and transmitted to the transmission fiber 104 on the side of the optical receiver 103. The operation state of each optical amplification repeater 101 is on the side of the optical receiver 103. Centralized monitoring. The monitoring method of the optical amplification repeater 101 in this system will be described below.

FIG. 5 is a block diagram showing an embodiment of the optical transmitter 102 shown in FIG. In FIG. 5, the sub-signal circuit 106
Is a sub-signal having the content of calling the optical amplification repeater designated with a small amplitude and low speed with respect to the main signal from the main signal circuit 105, and the modulator 107 is a signal obtained by superimposing the sub-signal on the main signal. The waveform is sent to the drive circuit 108 to modulate and drive the semiconductor laser 109. The output light from the semiconductor laser 109 has an optical waveform in which the sub-signal is superposed at low speed with a small modulation degree in addition to being modulated by the main signal. After the sub-signal specified by the optical amplification repeater is transmitted, the sub-signal of the specified optical amplification repeater will be transmitted.Therefore, set a suitable time interval so that the sub-signals specified by the next optical amplification repeater do not overlap. Send a signal. In this way, the optical transmitter 102 sequentially transmits the sub-signals designated by the optical amplification repeaters to the respective optical amplification repeaters 101, and the transmitted sub-signals are transmitted to the respective optical amplification repeaters 10.
1 to reach the optical receiver 103.

FIG. 1 is a block diagram showing an embodiment of the optical amplification repeater 101 shown in FIG. A coupler 118 is inserted between the input fiber 117 and the semiconductor optical amplifier 119 to
A part of the input signal light is converted into an electric signal by the electric converter 122 and amplified by the amplifier 123, and the low-pass filter 124
The sub signal is taken out through the local station, the local station call identification circuit 125 determines whether the optical transmitter 102 has designated the local station, and the result is sent to the control circuit 126.

The semiconductor optical amplifier 119 and the output fiber 12
A coupler 120 is inserted between 1 and a part of the output power from the semiconductor optical amplifier 119 is branched and the
It is guided to an output power measuring circuit (not shown) through the electric converter 131 and the amplifier 132, and the input signal light power is measured. Also on the input side, the output of the amplifier 123 is guided to an input power measuring circuit (not shown), and the input signal light power is measured.

The semiconductor optical amplifier 119 is a temperature control circuit 13
The temperature of the semiconductor optical amplifier 119 is controlled by 0, and the temperature of the semiconductor optical amplifier 119 is measured.

Input signal light power, output signal light power, drive current to semiconductor optical amplifier 119, semiconductor optical amplifier 11
The information in the repeater such as the temperature of 9 and the amplification degree is encoded by the encoding circuit 1.
It is encoded by 27, enters the optical amplifier driving circuit 129 through the modulator 128, and is sent to the semiconductor optical amplifier 119.
However, the information in the repeater does not always continue to enter the optical amplifier drive circuit 129. Unless the local station call identification circuit 125 recognizes the local station designation, the control circuit 126 does not operate the encoding circuit 127 and the modulator 128, and the semiconductor optical amplifier 11 does not operate.
9 is driven by an unmodulated drive current.

When the local station call identification circuit 125 recognizes the local station designation, the control circuit 126 operates the encoding circuit 127 and the modulator 128 so that the drive current from the optical amplifier drive circuit 129 is modulated by the sub signal, The output light from the semiconductor optical amplifier 119 is output to the output fiber 121 in a form in which the sub signal is superimposed on the main signal. The frequency of the sub-signal is common to each optical amplification repeater.

As described above, each optical amplification repeater 10
1 transmits the in-repeater information to the optical receiver 103 side within a predetermined time only when designated by the optical transmitter 102.

FIG. 6 is a block diagram showing an embodiment of the optical receiver 103 shown in FIG. In FIG. 6, the transmission fiber 11
The input signal light from 1 is converted into an electric signal by the optical / electrical converter 112 and amplified by the amplifier 113. The amplified electric signal enters the main signal demodulator 114, but part of the amplified electric signal enters the low-pass filter 115, and only the sub-signal is extracted, and the sub-signal demodulation circuit 116 uses the repeater designation signal from the optical transmitter 102 and the optical amplification repeater. The in-repeater information from 101 is read and output. As a result, the operating state of each optical amplification repeater 101 can be monitored.

[0020]

As described above in detail, according to the present invention, only the optical amplification repeater instructed by the optical transmitter transmits the information in the repeater as a sub-signal and other optical amplification repeaters. Does not output a sub-signal, the deterioration of the main signal is limited to the amount when one sub-signal is superposed regardless of the number of optical amplification repeaters. Further, the optical receiver only needs to have one low-pass filter and one sub-signal demodulator.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a conventional optical amplification repeater.

FIG. 3 is a configuration diagram of a conventional optical receiver.

FIG. 4 is a system configuration diagram of an embodiment of the present invention.

FIG. 5 is a configuration diagram showing an optical transmitter according to an embodiment of the present invention.

FIG. 6 is a configuration diagram showing an optical receiver according to an embodiment of the present invention.

[Explanation of symbols]

 101 optical amplifier repeater 102 optical transmitter 103 optical receiver 104 transmission fiber

Claims (1)

Claim: What is claimed is: 1. A monitoring system for an optical amplification repeater in an optical transmission system, wherein an output signal light of an optical transmitter is transmitted to an optical receiver through a plurality of transmission fibers and an optical amplification repeater. The transmitter includes means for superimposing a first sub-signal for designating an optical amplification repeater on a main signal, converting the signal into signal light, and transmitting the signal light to a transmission fiber. The optical amplification repeater detects from the input signal light. When the first sub-signal designates its own station, the second sub-signal containing information in the repeater is used to modulate the drive current to the semiconductor optical amplifier that amplifies the input signal light. The optical receiver is provided with means for superimposing the sub-signal on the main signal of the input signal light and sending it to the transmission fiber, and the optical receiver includes means for detecting the second sub-signal from the input signal light and outputting the in-repeater information. Supervision of optical amplifier repeater characterized by having Method.