JPH03163924A - Output control system for optical repeater - Google Patents

Abstract

PURPOSE:To stabilize the transmission characteristics of incoming and outgoing lines even at the time of a fault such as the destruction of an optical fiber and to enable the monitor and control of a repeater by controlling the repeater group of the incoming line, as well by using a control signal for outgoing line to control the repeater group arranged at the outgoing optical fiber. CONSTITUTION:When a fault point 6 is generated, a line number signal and the control signal are not present on the incoming optical amplifier 10b and therefore, an optical output is made instable. According to control from an S station, an optical shutter 17a is opened through an optical shutter control circuit 15a and the output of the outgoing optical amplifier 10a is inputted to the incoming repeater 10b. By setting the frequency of a control signal 7a so as to be the incoming line the same as the outgoing line, the control signal 7a passes through a photodetector 12b and a narrow band filter 13b and can control the output of the incoming amplifier 10b similarly to the outgoing amplifier 10a. Therefore, when the fault is generated, an optical signal including the control signal 7a controls a repeater group 4 in the feedback line of the incoming optical fiber 2, as well and the transmission characteristic of the incoming feedback line is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an output control force type for an optical repeater (hereinafter referred to as "repeater") that directly amplifies an optical signal.

[Prior art] In optical communication systems that perform optical digital communications using optical fibers, locating fault points in optical cables and repeaters and monitoring and controlling repeaters are extremely important technologies for the maintenance and operation of the transmission system. .

For example, in an optical submarine cable, when a fault occurs in the transmission system, control signals 123 are sent from the base station to each repeater to locate the repeater section where the fault is located.

FIG. 2 is a schematic diagram of a conventional repeater control method. In the same figure, d3, 1 and 2 are the down and up optical fibers 1a
, 1b, Ic, . . . 1n are the downlink optical fibers (
Viewed from station S>, 2a, 2b. 2C, . . . 2n are optical fibers for each uplink section, 3 and 4 are multistage repeater groups 3a,
3b, 3c. ...3n and 4a, 4b, 4c, -
4 n is a downlink and uplink stage repeater, 5 and 6 are failure points, 7a and 7b are control signals sent from S and T stations, respectively, and 8S and 8t are transmissions from S and T stations, respectively. 9S and 9t respectively indicate the receiving sections of the S station and the T station. In addition, Fig. 2 shows a case where the failure point 5.6 occurs in the repeater 3C to 3d section and 40 to 4d section, and a loop back L is formed in the repeater 3C and 4C section by the control signal 7a from the S station. An example is shown below.

When a failure occurs, the repeater group 3 is
．． 4 is looped back, and the repeater section where the failure has occurred is located depending on whether the transmission path is normal or abnormal.

Generally, each stage repeater 3a-n, 4a-n has a gain commensurate with the loss of the section optical fibers 1a-n, 2a-n, and compensates for signal attenuation in the section optical fibers lan, 28--. are doing. By the way, each section optical fiber 1a to n, 2a
Since the 10 loss of ~n is not constant and also changes depending on the temperature, installation conditions, etc., each stage repeater 3a~n,
It is necessary to constantly control the gains of 4a to 4n.

[Problem to be Solved by the Invention] However, when a cable failure occurs at failure points 5 and 6, the control signal '? Since it is not possible to transmit s7b, it is impossible to control the outputs of uplink repeaters 4a-c. Therefore, the transmission characteristics of the two uplink optical fiber lines from the repeater 4C to the S station side are not guaranteed, and there is a problem in that the S station cannot measure the line status after a failure occurs.

In addition, since the output of the uplink TL units 4a to 4C is not controlled, the loopback from the downlink relays 3a to c to the S station is performed in order to remotely monitor the operating status of the downlink repeaters 3a to There were also cases where it became impossible to transmit monitor information to a transmitting station using an uplink. For this reason,
Conventionally, when a bidirectional cable becomes a problem, the transmission characteristics and repeaters cannot be monitored or controlled, which poses a problem in troubleshooting the problem.

In this case, the present invention has been made in order to solve the problems of the conventional method, and it is possible to normally monitor and control transmission characteristics and a group of repeaters even if a breakage failure occurs in an optical communication system. The object of the present invention is to provide a child-friendly repeater output control method.

[A Thousand Steps to Solve the Problem] The above problem can be solved by the optical repeater output control method of the present invention,
The output of the group of optical repeaters of the optical transmission line, which is constructed by inserting multiple optical repeaters in multiple stages to directly amplify the optical A3 propagating in the upstream and downstream optical fibers, is controlled by the control signal from the transmitting station. In the output control method of an optical repeater, the output of each downlink repeater is controlled by the control signal sent from the transmitting station, and the output of each downlink repeater is controlled by the repeater of a desired stage based on the control signal. The above configuration means is characterized in that a loopback is formed between the uplink repeaters, and the outputs of the uplink repeaters are also controlled by the looped back control signal. The precepts are attained by children.

[Function] Since the present invention has taken the above-mentioned measures, it utilizes a hand-held control signal for the main line signal transmitted from the transmitting station that was controlling the output of the repeater group on the downlink of the optical fiber cable. At the time of testing or when a failure/damage occurs, a loopback 5 transmission line is formed between the downlink repeater of the desired stage and the uplink repeater of the corresponding stage, or the control {ii. By performing feedback transfer and sharing the output control of the uplink repeater group, it is possible to maintain transmission characteristics and monitor and control the repeater group, thereby accurately measuring, diagnosing, and locating the line status after a failure occurs.

[Example] Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a relay steamer for explaining the output control method of the relay according to the present invention. In the first section, in order to make the explanation easier to understand, it is assumed that a cable failure occurs at failure points 5 and 6 as in FIG. 2, and an example of the structure of the relays 3c and 4c in the preceding stage is shown as an example. Furthermore, when viewed from the S station, the subscript a is used for the circuit installed in the downlink repeater 3C, and the subscript b is used for the circuit installed in the upstream repeater 4C.

In the figure, 10a. iob is an optical amplifier such as a semiconductor laser amplifier or an optical fiber amplifier, 11a and 1lb are optical branch circuits that branch optical fibers from the main optical fiber, and 12
a, 12b are detectors for converting optical signals into electrical signals 6, 13a.
13b is a narrow band filter (B.P.F.) tuned to the frequency of the control signal 7a to extract the control signal 7a. 14a
, 14b are control circuits for controlling the optical outputs of the optical amplifiers 10a and 10b, and 15a and 15b are optical circuits I7 that receive control commands from S8 and control the optical signal receiver 17, which will be described later.
Ivy control circuit, 16a, 16b are optical branch circuits, 17a,
17b is an optical shutter, 18a, 18EN is an optical shutter 1
Optical multiplexers for multiplexing the outputs of 7b and 17a onto main optical fibers 1 and 2 are shown, respectively.

Now, the optical amplifier 10a outputs the control signal 7a superimposed on the main line signal (U) transmitted from the transmitter 8S of the S station.
The light is not received by the detectors 12a and 12b, and is controlled by the control circuit 14a so that the amplitude thereof is always constant, thereby keeping the optical output constant. On the other hand, due to the occurrence of the failure point 6, the upstream optical amplifier 10b loses the main line signal r d3.
Since there is no control light and control beam, the light output is unstable. Similarly, other repeaters 4. b, 4
．． 43 at a (not shown), the output will be unstable. Therefore, in the present invention, under control from the S station, the optical shutter 17a is interrupted via the optical switch control circuit 15a, and the output of the downlink optical amplifier iQa is transmitted via the branch circuit 16a and the optical multiplexer 18b. Input 9 is input to the upstream repeater 10b. Iil
lgoi: i ';'j 7 a no 1. ', 1 wave number is made the same as the upstream and downlink lines, the control point 7a
can control the output of the upstream lq width amplifier 10b in the same way as the downstream amplifier 10a through the Bo1 head detector 12b and the narrowband filter 13b.

Therefore, in the present invention, the optical signal including the control signal Q7a stably connects the repeater group 3 disposed on the downlink optical fiber 1, and also controls the repeater group 4 on the return line of the uplink optical fiber 2 when a failure occurs. And the transmission characteristics of the upstream feedback line f! +- can be stabilized.

Note that the optical shutters 17a and 17b are opened only when a system failure occurs. In addition, the optical shutter 17ayl
Since the crosstalk of 7b is negligible, it does not affect normal system operation or transmission characteristics.

In the above explanation, the case where the uplink repeater group 4 is controlled by the control signal bow 7a sent from the S station is taken as an example. vessel? ! The same is possible when controlling ¥3, and at that time the optical shutter 7b is opened.

[Effects of the Invention] As described above, the present invention is arranged in a downstream optical fiber.
By controlling the uplink repeater group 4 using the downlink control signal 87a that controls the repeater group 3, the uplink and downlink transmission characteristics can be stabilized and the repeater monitoring and control becomes possible.

Therefore, the present invention can be applied to an optical submarine coupler or various optical communication systems using repeaters, and it becomes possible to measure the transmission characteristics of the system and transmit repeater monitor information, thereby improving the maintenance ability of the system. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a repeater for explaining a repeater output control method 9 according to the present invention, and FIG. 2 is a schematic diagram of a conventional repeater output control method. 1...Downward optical fiber Ia. Ib, IC...1n...Downlink section optical fiber (as seen from S station) 2...Uplink optical fiber 2a, 2b, 2c...2n...Uplink Sectional optical fiber 3...■ multi-stage repeater groups 3a, 3b, 3c, . ...4n...1-stage repeaters 5, 6...Failure points 7a, 7b-? lill swearing 8s, 8t・
...Transmission section 95.9t of S month and T station...S station and T
Receiving section 10a, 10b of the station - Optical J: +i width unit 11a, llb... Optical branch circuit 12a, 12b... BoI detector (summer light unit) 1
3 a, 1 3 L') - narrow area noirta (B.
P. F) 10 1 4a, 1 5a, 1 6a, 1 7a, 1 8a, 14b...Control circuit 15b...Optical shutter control circuit 16b...Optical branch circuit 17b...Optical shutter 18b...Optical combiner Wave device 11

Claims (1)

[Claims] 1. The output of a group of optical repeaters of an optical transmission line configured by inserting a plurality of optical repeaters that directly amplify optical signals propagating in upstream and downstream optical fibers from a transmitting station. In the output control method of an optical repeater controlled by a control signal, the output of each downlink repeater is controlled by the control signal sent from the transmitting station, and the output of each downlink repeater is controlled by the control signal at the repeater of a desired stage. An output control method for an optical repeater, characterized in that a loopback is formed between uplink repeaters of corresponding stages based on the above control signal, and the outputs of the uplink repeater group are also feedback-controlled using the looped back control signal.