JPH03117941A - Submarine optical communication system - Google Patents

Abstract

PURPOSE:To immediately discriminate it on the terminal station side whether a control signal is actually received by a submarine optical repeater or not by providing the submarine optical repeater with a means which immediately returns the response to the control signal addressed to its own repeater. CONSTITUTION:The light beam which is propagated in an incidence transmission line 1 and is emitted from its front end part is converted to an electric signal by an photoelectric converting circuit 2 and is supplied to a identifying and reproducing circuit 4 after correction of the frequency characteristic of the transmission line in an equalizing amplifying circuit 3. The output of this circuit 3 is supplied to a timing generating circuit 6 also through a band-pass filter circuit 5, and the timing signal generated by the circuit 6 is supplied to the circuit 4. A monitor and control circuit 7 demodulates the control signal superposed by modulation (PCM pulse position modulation or the like) of transfer data from data identified by the circuit 4; and when this control signal is a command addressed to its own repeater, this command is executed. Thus, it is immediately discriminated on the terminal station side whether the control signal is received by the submarine optical repeater or not.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical submarine communication system that uses optical cables as submarine transmission lines.

(Prior art) In an optical submarine communication system that uses optical cables as submarine transmission lines, transmitted data and control signals superimposed on it by modulating the data are transmitted via multiple optical submarine repeaters installed between terminal stations. It is configured to transmit and receive data between terminal stations.

Each optical submarine repeater sends monitoring signals such as temperature and operating status to the terminal station in accordance with commands based on control signals from the terminal station.

(Problems to be Solved by the Invention) In the conventional optical submarine communication system described above, each optical submarine repeater only performs control operations in accordance with commands from the terminal station, but does not return responses to the commands themselves. For this reason, it is not immediately clear at the terminal station whether the command has actually been received by the destination optical submarine repeater, which poses a problem in system reliability.

(Means for Solving the Problem) In the optical submarine communication system of the present invention, when each optical submarine repeater receives a control signal addressed to its own device from a terminal station and demodulates it, it generates an amplitude of a sine wave of a frequency unique to its own device. It is configured to improve the reliability of the system by providing means for returning a response to the terminal station by modulating and transmitting reproduced transfer data with a modulated and delayed signal.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an optical submarine repeater in an optical submarine communication system according to an embodiment of the present invention.
is an optical transmission line on the incident side, 2 is an optical/electric conversion circuit, 3 is an equalization amplifier circuit, 4 is an identification/regeneration circuit, 5 is a bandpass filter circuit, 6 is a timing generation circuit, 7 is a monitoring/control circuit, 8 is a modulation circuit, 9 is an electric/optical conversion circuit, 10 is an optical transmission line on the output side, 11 is an oscillation circuit, 12 is an AND gate, 13 is a delay circuit, and 14 is an OR gate.

The light beam that propagates within the input side transmission line 1 connected to the preceding stage optical submarine repeater or terminal station and is emitted from its tip is as follows:
The signal is converted into an electrical signal by an optical/electrical conversion circuit 2 composed of an APD or the like, and after the frequency characteristics of the transmission path are corrected by an equalization amplifier circuit 3, it is supplied to an identification/regeneration circuit 4. The output of the equalization amplifier circuit 3 is also supplied to a timing generation circuit 6 via a bandpass filter circuit 5, and a timing signal generated from this is supplied to an identification/regeneration circuit 4. The signal identified and reproduced based on this timing signal undergoes modulation necessary for superimposing monitoring information in a modulation circuit 8, and then is converted into an optical signal by an electric/optical conversion circuit 9 composed of a laser diode or the like. , enters the optical transmission line 10 on the output side connected to the next optical submarine repeater or terminal station, and propagates therein.

The monitoring/control circuit 7 demodulates the control signal superimposed by modulating the transfer data (PCM pulse position modulation, etc.) from the data identified by the identification/reproducing circuit 4, and converts this control signal into a command addressed to the own device. If so, run this. The monitoring/control circuit 7 supplies the modulation circuit 8 via the OR gate 14 with monitoring information such as the operating temperature requested to be sent by a command received from the terminal station. The modulation circuit 8 is
By modulating the regenerated transfer data output from the identification/regeneration circuit 4 by position modulation of PCM pulses, the monitoring information of the end station array is superimposed on the transfer data, and the electrical/
It is supplied to the optical conversion circuit 9.

When the monitoring/control circuit 7 receives and demodulates a command addressed to its own device, it supplies the demodulated command as it is to one input terminal of the AND gate 12 . A sine wave of a predetermined frequency is supplied from the oscillation circuit 11 to the other input terminal of the AND gate 12. Therefore, and gate 1
2, the demodulated command is amplitude-modulated with a sine wave of a predetermined frequency and output as a response signal, which is supplied to the modulation circuit 8 via the delay circuit 13 and the OR gate 14.

This delay circuit 13 is provided to avoid temporal irregularities between the command sent from the terminal station and the response signal output from the AND gate 12.

The terminal station that sent the above command or the terminal station on the other side receives a response signal from the optical submarine repeater after a predetermined delay from the command destined for the optical submarine repeater, and the frequency of this response signal is Since this is the predetermined frequency assigned to the destination optical submarine repeater, it can be immediately determined that this command has been correctly received and demodulated by the destination optical submarine repeater.

(Effects of the Invention) As explained above in detail, the optical submarine communication system of the present invention is equipped with a means for the optical submarine repeater to immediately return a response to the control signal addressed to itself, so that the control signal is actually The terminal station can immediately determine whether or not the signal has been received by the optical submarine repeater, which has the effect of improving system reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an optical submarine repeater in an optical submarine communication system according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Optical transmission line on the incident side, 2... Optical/electric conversion circuit, 3... Equalization amplifier circuit, 4... Identification/regeneration circuit, 5
...Band pass filter circuit, 6...Timing generation circuit, 7...Monitoring/control circuit, 8...Modulation circuit, 9...
・Electrical/optical conversion circuit, 10... Optical transmission line on the output side, 1
1...Oscillation circuit, 13...Delay circuit.

Claims (1)

[Claims] In an optical submarine communication system in which transfer data and monitoring and control signals superimposed on the transfer data by modulation of the transfer data are transmitted and received between terminal stations via a plurality of optical submarine repeaters installed between the terminal stations, Each optical submarine repeater receives a control signal addressed to its own device from the terminal station, demodulates it, and uses this demodulated control signal to modulate the reproduced transfer data with a signal that is amplitude-modulated with a sine wave at a frequency unique to its own device, and then transmits it. An optical submarine communication system characterized by being equipped with a means for returning a response to a terminal station.