JPH04100421A - End box for submarine cable system - Google Patents

Abstract

PURPOSE:To make various kinds of monitoring to a light reproducing repeater by providing an instruction reception/demodulation circuit which extracts a loop back controlling instruction from an optical signal inputted in the direction A and a loop back circuit which repeatedly returns an input optical signal to another optical fiber. CONSTITUTION:An optical signal transmitted from a submarine optical cable 6 is inputted to an instruction reception/demodulation circuit 3 through an input optical fiber 1. A control signal 5 demodulated by means of the circuit 3 is inputted to a loop back circuit 4. The circuit 4 returns the optical signal from the fiber 1 to an output optical fiber 2 upon receiving the control signal 5. Therefore, not only the error-free condition of all submarine repeaters can be monitored from a terminal station, but also each repeater can be monitored by stopping the light returning operation at an end box when the operation of a certain repeater becomes doubtful.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to an optical submarine cable system, and particularly to an end box used for waterproofing, power supply, or fiber tip treatment during optical submarine cable installation.

Conventional technology Due to the limitations of the mounting capacity of the end box itself, the end box used in the conventional optical submarine cable system simply connects the input optical fiber 1 to the output optical fiber t<2 in the second (21) It was just a matter of connecting.

Problems to be Solved by the Invention This conventional end box connects the upstream and downstream regenerative repeaters of the optical submarine repeater installed between the end box and the land terminal station, and connects the optical fiber from the upstream side within the entopolux. By connecting the two to the downstream, it seems as if they are connected in series.
It has the characteristic of returning the signal back to its own station. This makes it possible to confirm that all repeaters being installed are error-free.

However, this monitoring system has a problem in that the optical regenerative repeater monitoring circuit (11 in Figure 3) built into the optical submarine repeater makes it impossible to monitor various aspects of the optical regenerative repeater.

As can be seen from Fig. 3, the monitor command in the A direction enters the optical regenerative repeater 11'') and is received as a normal command by the optical regenerative repeater monitoring circuit 11 as the command (A>12). This is good because no commands normally come from the time side, but if a conventional end box like the one shown in Figure 2 is installed on the B side (end side of the optical submarine cable 6'), commands will not be received. (
A) 12 is looped back, and commands (B) 13 and 1- are input again to the monitoring circuit 11.9 As a result, the monitoring circuit 11 is unable to operate normally, and it is impossible to monitor the optical regenerative repeater. Become.

The present invention has been made in view of the above-mentioned conventional circumstances.'7)
Therefore, it is an object of the present invention to solve the above-mentioned problems inherent in the prior art. Our goal is to provide the best possible FT standard end boxes for submarine cable systems.

Means for Solving the Problems In order to achieve the above object, the end box for a submarine cable system according to the present invention includes a command reception/demodulation circuit that extracts at least a loopback control command from an input optical signal in the A direction. , and a loopback circuit that is controlled by the demodulation command and loops back the input optical signal from the A direction to another optical fiber and returns it back to the input direction.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. FIG.

Figure 1? For reference, an optical signal transmitted from an optical submarine cable 6 is inputted to a beach receiving and demodulating circuit 3 via an input optical fiber 1. Here, the demodulated control signal 5 is Luano! Evening #! 4 is input. The loopback circuit 4 receives the control signal 5 and returns the light from the input optical fiber 1 (1-1) to the output optical fiber 2 in the X direction. 1-force/100, and how to invert the control and force release τ depends on the conditions of use.

The command reception demodulation circuit 3 can be configured by a decoder, for example, and has a frequency of 28t) MHz: 421EH.
In the case of a line with a transmission speed of Output as 5. For example, Hikarisha! The operation of the lube bank circuit 4, which is configured by When the signal becomes 0\, the loop bar circuit 4 stops its loop bar function and acts so that the signal input to the input optical fiber 1 is not output to the output destination loop 2.

Effects of the Invention L-1 As explained above,', :Yo(This) By using the end box of the present invention, it is possible to
Is the optical signal return 1-1 full-scale submarine repeater error-free with a bundle of Enpo-Lux? They're just monitoring me from the terminal station.
However, if a suspicious r':I point occurs in a repeater, it is possible to monitor each repeater by filtering out the optical return of one end box.

[Brief explanation of the drawing]

Figure 1 is a professional configuration diagram showing one embodiment of the present invention;
The figure is a block diagram of a conventional end box, and Figure 3 is a block diagram of a monitoring system for installed optical submarine repeaters.
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Claims (2)

[Claims] (1) At least a loopback control command is sent from the input optical signal from the A direction in the end box installed at the tip of the already laid submarine cable when the intermediate laying of a submarine cable system is completed in which the laying is carried out over two or more times. and a loopback circuit that loops back the input optical signal from direction A to another optical fiber and sends it back to direction A, which is controlled by the demodulation command of the command reception and demodulation circuit. An end box for submarine cable systems featuring the following. (2) If the command reception/demodulation circuit decodes the loopback control command extracted from the optical signal input from the A direction and the loopback control command is a loopback function blocking command, the loopback circuit receives the command. - The end box for a submarine cable system according to claim (1), further characterized in that it stops its loopback function upon receiving a control signal output from the demodulation circuit.