JPS63175541A - Sea bottom optical repeater - Google Patents

Abstract

PURPOSE:To facilitate retrieval at the fault point of an optical sea bottom cable by providing an optical switch applying tentative loopback of an input terminal of each recovery repeater section to the output terminal of an opposite side repeater section. CONSTITUTION:Just after a control signal 8 passes through an optical switch 2a via a forward pass recovery repeating section 11, the optical switch 2a is switched. A control signal 9 passing through the optical switch 2a is a reflected light 10 at the fault point of the optical fiber, passes through the optical switch 2a, recovered by a return path recovery repeating section 12 and sent to a terminal station sending a control signal. The difference of the reception time of the recovered reflected light from the sent time of the control signal, that is, the division of the delay time by the propagation time per unit length of the optical fiber gives the measurement of the distance of the fault point of the optical fiber line including the sea bottom repeater. Thus, the location of the fault point of the optical fiber line including the sea bottom optical repeater is detected easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is used in an optical communication system installed on the ocean floor.

The present invention particularly relates to a submarine optical repeater that can easily search for failure points in optical submarine cables.

〔overview〕

The present invention provides a submarine optical repeater equipped with two regenerative repeaters that regenerate each optical signal on the outbound and return routes, and temporarily connects the input end of each regenerative repeater to the output end of the opposite repeater. By installing an optical switch that connects back and forth, it is possible to easily search for failure points in optical submarine cables.

[Conventional technology]

Conventionally, this type of submarine optical repeater has a repeater characteristic monitoring circuit, but does not have an optical return circuit for searching for a fault point in an optical fiber, which is a path for optical signals.

Conventional technology uses the "pulse reflection method", "current/voltage method", and "capacitance method" (international communications research) to search for this fault point when cutting a submarine cable. 1k109) and "Optical Pulse Reflection Method" (Practical Technology of Optical Communication/Sanpo Publishing).

[Problem that the invention seeks to solve]

However, in each of the above-mentioned methods, the optical pulse reflection method cannot search for failure points in optical fibers that are farther away than the submarine optical repeater closest to the end station.

In addition, each fault point search method using the power feed line as an intermediary is only effective when the optical submarine cable is completely disconnected, that is, when the power feed line is disconnected. The disadvantage is that it is not possible to search for faults that occur in optical fibers.

SUMMARY OF THE INVENTION An object of the present invention is to solve this drawback and provide a submarine optical repeater that can easily search for failure points occurring in optical fibers.

[Failure to solve the problem]

The present invention provides a submarine optical repeater equipped with an outgoing regenerative repeater that regenerates the outgoing optical signal and a return regenerative repeater that regenerates the incoming optical signal. An optical switch is provided in the optical input and optical output paths to temporarily connect the input of each relay unit to the output of the other relay unit, and the optical switch is activated according to a control signal detected from inside each relay unit. It is characterized by being equipped with a controller for switching control.

The time for loopback connection is the time equivalent to one round trip propagation time of one relay section of the optical signal.

[Effect]

The submarine optical repeater of the present invention has a configuration in which optical switches are arranged at the input end and output end of each regenerative repeater, and a controller for driving these optical switches is arranged in each regenerative repeater. . These optical switches are driven by control signals sent from the transmitting end station, and temporarily form an optical folding circuit in the optical fiber that is the path for the optical signal.

The time for configuring this optical return circuit is calculated as follows:
Assuming that this corresponds to the general round-trip transmission time, if a fault occurs in the optical fiber, the reflected wave from the faulty part will return to the terminal station via the optical return circuit, making it possible to detect the point of fault.

〔Example〕

Next, embodiments of the present invention will be described using the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

In FIG. 1, in the submarine optical repeater 1, the optical fiber 4a on the outgoing side of the first optical submarine cable 4 connected to one end station (not shown) is connected to the input end 11a of the outgoing regenerative repeater 11. The optical fiber 14a on the outgoing side of the second optical submarine cable 14 connected to the other end station (not shown) is connected to the output end 11.
connected to b. Similarly, the input terminal 1 of the return regeneration relay section 12
2a is connected to the optical fiber 14b on the return side of the second optical submarine cable 14, and the output end 12b is connected to the optical fiber 4b on the return side of the first optical submarine cable 4.

These input ends 11a, 12a and output ends 11b, 1
2b, light receivers 5a, 5b, regenerative amplifiers 6a, 6b, and light emitters 7a, 7b are connected, respectively.

Here, the feature of the present invention is that the output end 11b
A first optical switch 2a is connected between the input end 12a and each of the optical fibers 14a and 14b on the outward and return sides of the second optical submarine cable 14, and the first optical switch 2a is connected between the output end 12b, the input end 11a and the first The second optical switch 2b is connected between each of the optical fibers 4a and 4b on the outgoing and inbound sides of the optical submarine cable 4. Further, the first optical switch 2a is configured to temporarily function as an optical folding circuit by a control signal inputted from the optical fiber 4a or a controller 3a inputted via the regenerative amplifier 6a.

The second optical switch 2b is configured to temporarily function as an optical return circuit by a controller 3b into which a control signal manually inputted from the optical fiber 14a is inputted via a regenerative amplifier 6b.

Optical switch 2a or 2 switched to optical return circuit
After holding the optical signal for one round-trip transmission time of one relay section length, b returns to the initial state.

FIG. 2 is an explanatory diagram when the optical switch 2a is switched.
This shows the state in which the optical switch 2a is switched immediately after passing through point a. The control signal 9 that has passed through the optical switch 2a becomes reflected light 10 at the failure point of the optical fiber, passes through the optical switch 2a, is regenerated by the return regenerative repeater 12, and is transmitted to the terminal station that sent the control signal.

In this way, the control signal sent from the terminal station is sequentially regenerated and relayed to the point of failure in the optical fiber, and the reflected light generated at the failure point is returned by an optical switch, regenerated and relayed again, and received at the control signal sending terminal station. By dividing the difference between the sending time of the control signal and the receiving time of the reproduced reflected light, that is, the delay time, by the propagation time per unit length of the optical fiber, the distance to the fault point of the optical fiber line including the submarine optical repeater can be measured. can.

〔Effect of the invention〕

As described above, the present invention has the effect of easily detecting the position of a fault point in an optical fiber line including a submarine optical repeater.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2 is an explanatory diagram of the above embodiment. DESCRIPTION OF SYMBOLS 1... Submarine optical repeater, 2a, 2b... First and second optical switch, 3a, 3b-controller, 4... First optical submarine cable, 4a, 4b... Outbound and Return path optical fibers, 5a, 5b...Receiver, 6a, 6b...
...Regenerative amplifier, 7a, 7b...Light emitter, 8.9...
・Control signal, 1°... Reflected light, 11... Outgoing path regenerative repeater, 11a, 12a... Input end, llb, 12b
...Output end, 12... Return path regeneration relay section, 14...
Second optical submarine cable, 14a, 14b...optical fibers for outbound and return routes.

Claims (2)

[Claims] (1) In a submarine optical repeater equipped with an outgoing regenerative repeater that regenerates the outgoing optical signal and an inbound regenerative repeater that regenerates the inbound optical signal, the optical input and the optical In the output passage,
An optical switch is provided to temporarily connect the input of each relay unit to the output of the other relay unit, and a controller is provided to switch and control the optical switch according to a control signal detected from inside each relay unit. A submarine optical repeater featuring: (2) The submarine optical repeater according to claim (1), wherein the time for loopback connection is a time corresponding to one round trip propagation time of one repeat section of an optical signal.