JPH02146831A - Optical terminal station equipment - Google Patents

Abstract

PURPOSE:To easily detect a fault of a submarine cable in which many faults take place by providing a function sending part of an optical signal output from an optical transmission section to an optical reception section, and providing an optical signal input power measuring function to the optical reception section. CONSTITUTION:An electric signal inputted to an optical terminal station equipment 9 is converted into an optical signal by an optical transmission section 7 and the signal is sent to the optical terminal station equipment 9 of an opposite station via an optical fiber 1 in a submarine cable 2 and a repeater 5 in an optical submarine repeater 4. On the other hand, an optical signal sent from an optical terminal station equipment of an opposite station is inputted to an optical reception section 8 having a photoelectric conversion function in the equipment 9 via a repeater 5' in the repeater 4 and an optical fiber 1'. Moreover, the optical signal output power of the repeater 5 is measured by the repeater 5' via a loopback circuit 6 and its information is sent to a reception section 8. Similarly, the optical signal output power in the repeater 5' is measured by the repeater 5 via a loopback circuit 6' and sent to an opposite optical terminal station.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical terminal station device, and more particularly to an optical terminal station device installed on land in an optical submarine cable communication system.

[Conventional technology]

FIG. 2 is a block diagram showing an example of a conventional optical terminal equipment. A conventional example will be explained using FIG.

The electrical signal input to the optical terminal device 13 is converted into an optical signal by the optical transmitter 11 having an electrical-to-optical conversion function, and is transmitted to the optical fiber 1 in the optical submarine cable 2 and the optical submarine repeater 4.
The received signal is sent to the opposite terminal station via the regenerative repeater 5 inside.

On the other hand, the optical signal sent from the opposite terminal station is transferred to a regenerative repeater 5' having the same function as the regenerative repeater 5, and an optical fiber 1'.
The signal is transmitted to the optical receiver 12 having an optical-to-electrical conversion function and converted into an electrical signal.

Furthermore, the regenerative repeaters 5 and 5' in the optical submarine repeater 4 have loopback circuits 6,6'. The regenerative repeaters 5 and 5' have a function of measuring the optical power of the input optical signal, and the optical signal output power of the regenerative repeater 5 is measured by the regenerative repeater 5' via the loopback circuit 6. optical receiver 12
Other information is transmitted. Similarly, the optical signal output power of the regenerative repeater 5' is measured by the regenerative repeater 5 via the loopback circuit 6', and the information is transmitted to the opposite terminal station.

Furthermore, an optical signal transmitted through the optical fiber 1 and inputted to the regenerative repeater 5 also receives the optical signal input power from the regenerative repeater 5.
The information is transmitted to the optical receiver 12 via the loopback circuit 6, the regenerator 5', and the optical transmission path of the optical fiber 1.

By the above-described operation, the optical signal power input to the optical submarine repeater 4 and the optical signal output power from the optical submarine repeater 4 can all be observed by the optical terminal device 13 or the optical terminal device of the opposite station.

[Problem to be solved by the invention]

In the conventional advanced station device described above, when a failure 3 occurs on the optical fiber 1 in the optical submarine cable 2 and the optical signal input power of the regenerative repeater 5 decreases, the optical input power is transmitted to the regenerative repeater 5. Measured loopback circuit 6 and regenerative repeater 5
', but when viewed from the input point of the regenerative repeater 5, it is impossible to distinguish whether the optical signal output power of the optical transmitter 11 has decreased or the power has decreased due to the failure 3.

Further, even if a failure 3' occurs, there is a drawback that the failure cannot be detected early because the optical receiver 12 does not have a function to measure the optical input power.

[Means for Solving the Problems] An optical terminal device of the present invention includes an optical transmission section and an optical reception section connected to an optical submarine cable. It has the optical transmitter that branches and sends out a part of the optical signal, and the optical receiver that receives and measures the optical signal of the part.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

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

In FIG. 1, an electrical signal input to an optical terminal device 9 is converted into an optical signal by an optical transmitter 7 having an electro-optical conversion function, and is converted into an optical signal by an optical fiber 1 in a submarine cable 2 and a regenerative repeater in an optical submarine repeater 4. 5 to the optical terminal equipment of the opposite station. On the other hand, the optical signal sent from the optical terminal equipment of the opposite station is transmitted via the regenerative repeater 5' in the optical submarine repeater 4 and the optical fiber 1' to the optical receiver having a photoelectric conversion function in the optical terminal equipment 9. 8 is input. Further, the optical signal output power of the regenerative repeater 5 is transmitted to the regenerative repeater 5 via a loopback circuit 6.
' and the information is transmitted to the optical receiver 8. Similarly, the optical signal output power of the regenerative repeater 5' is measured by the regenerative repeater 5 via the loopback circuit 6', and the information is transmitted to the opposite terminal station. Further, the power of the optical signal propagated through the fiber 1 is measured by the regenerative repeater 5 and transmitted to the optical receiver 8 via the loopback circuit 6.

On the other hand, the optical signal power sent from the opposite terminal station is transmitted to the regenerative repeater 5.
', and the information is transmitted to the opposite optical terminal via the loopback circuit 6'.

By the above-described operation, all the optical power at the input/output points of the submarine repeater 4 can be measured by the optical terminal equipment. That is, when a failure 3 occurs in a part of the optical fiber 1 and the optical signal power at the input point of the regenerative repeater 5 decreases, the value P 2 (d B
m) is measured by the regenerative repeater 5, and the information is transmitted through a path including the loop bark circuit 6, the regenerative repeater 5, the optical fiber 1, and the optical receiver 8.

On the other hand, the optical signal output power from the optical transmitter 7 is
It is measured by the optical signal power measuring function of the optical receiver 8 by the loopback circuit 10 in the terminal station. The measured value is P
H (dBm) and the normal optical loss of optical fiber 1' is α (dB), then α-Pl-P2, so α≠P
, -P2, it can be determined that there is a cable failure.

Also, the optical transmitter 7 whose measured value should be PI (dBm)
If the optical output power from the optical transmitter 7 is P1', this means that the optical output power of the optical transmitter 7 has fluctuated, and the fault is not on the cable but within the optical terminal station.

Similarly, the optical signal output of the regenerative repeater 5' is P3 (dBm)
Then, when the input to the optical receiver 8 is measured as P4 (dBm) and the cable loss of the optical fiber 1' is α', α
=P, -P4, there is no fault on the cable, and the cause is either a drop in the output power of the regenerative repeater 5' or the input power measuring circuit of the optical receiver 8.

[Effects of the Invention] As explained above, the present invention has a function of transmitting a part of the optical signal output from the optical transmitting section to the optical receiving section, and a function of measuring the optical signal input power in the optical receiving section. This has the effect of easily detecting faults in submarine cables, where faults occur most often.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an example of a conventional optical terminal equipment. 1.1'... Optical fiber 2... Optical submarine cable, 3.3'... Failure point, 4... Optical submarine repeater, 5゜5'... Regenerative repeater, 6.6' . . . Loopback circuit, 7, 11 . . . Optical transmission section, 8, 12 .

Claims (1)

[Claims] An optical terminal device having an optical transmitter and an optical receiver connected to an optical submarine cable, the optical transmitter branching and transmitting a part of the optical signal transmitted to the optical submarine cable, and the part of the optical signal being transmitted to the optical submarine cable. An optical terminal device comprising: the optical receiving section that receives and measures signals.