JPS58177040A - Optical data station device - Google Patents

Abstract

PURPOSE:To prevent mission of data when bypass of a station is switched during the operation of the system and to eliminate the adverse effect exerting on other stations, by providing a control means controlling the intensity of an optical reproducing output of an optical reproducing repeating installation to an optical data station. CONSTITUTION:An optical input is branched into two at an optical branching device 501 of an optical data station 500, one branched signal is inputted to an optical delay device 514 and the other optical reproducing relay device 503. The device 503 is controlled with a controller 517 connected to a power supply 518 of a power supply device. The device 503 is provided with an photoelectric conversion circuit 505, an AGC circuit 506 making the output amplitude of the circuit 505 constant, and an optical output adjusting circuit 509, etc. controlling the intensity of light of an optical after amplification and reproduction. The device 517 keeps the order of control of the device 516 and the circuit 509 in a prescribed order, allowing to prevent missing of data when the bypass of the station is switched during the operation of the system and to eliminate the adverse effect exerting on other stations.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical data station device, and in particular, to a device that can always transmit data without error even if an optical regenerative repeater is inserted into the transmission line during data transmission or conversely bypassed. The present invention relates to an optical data storage/control device that can perform the following operations.

The so-called optical data highway system, which connects multiple data stations using optical fiber transmission lines and transfers data between each other, takes advantage of the features of optical fiber transmission, such as large capacity, noise resistance, and low loss. nine systems,
It generally has a loop-shaped configuration as shown in Figure @1. 1F! In FIG. 1, 1.2.5 is an optical data station, and a plurality of terminals 4.5.6 are connected to each party data station. The optical data stations are connected in a ring by optical fiber transmission lines 7.8.9.10. Reference numeral 11 denotes a mourning center station/which has functions such as controlling data conversion between party data stations and monitoring line status.

The loop-type optical data highway system as shown in Figure 11!1 has the advantage of being able to save a great deal of transmission lines because it is only necessary to connect each optical data station with one optical fiber cable. However, on the other hand, there is a drawback that if one optical data station/(indicated by 2 in FIG. 1) fails and does not operate, communication of the entire system becomes impossible. In order to compensate for this drawback, a method has conventionally been used in which the inactive optical data station is bypassed, as shown by the broken line in FIG.

A common method for bypassing each optical data station is to use an optical switch as shown in FIG. 112. In FIG. 2, optical data station 2
The optical data signal +201 entering 00 is branched into two by an optical splitter 202, one directly enters an optical switch 203,
The other one enters the optical regenerative repeater 204 . Optical regeneration repeater 92
04 consists of a receiving section (optical signal/electrical signal converting section) 2o5 and a transmitting section (electrical signal/optical signal converting section) 206, and the data signal (converted into an optical signal) by the receiving section 205 is
The received data is sent to a requesting terminal (eg, 208) under the control of a multiplexer/demultiplexer*207. Conversely, when a terminal transmits data, the transmitted data enters the transmitter 206 via the multiplex/demultiplexer 207, is converted into an optical signal, and is sent out. If data cannot be sent to or received from each terminal, the data that has entered the receiving section 205 is sent as is to the transmitting section 206, where it is converted into an optical signal and sent out.

In the optical switch 206, the contacts 209 and 210 are normally connected, but if a failure occurs in the optical regenerative repeater 204 or the multiplex/demultiplexer 207, or if you want to disconnect these devices from the transmission path (for example, For inspection or expansion work), contacts 209 and 211 are switched to be connected, thereby bypassing this optical data station.

As optical switches used for such purposes, there are widely known types of optical switches that use optical fibers or prisms as movable parts and move the optical fibers or prisms from the outside using electromagnets. FIG. 3 shows an example of such an optical switch control method. When the switch 600 is open as shown in the figure, no current flows through the electromagnetic coil 302 in the optical switch 501, and the optical switch is closed. The movable part 605 is an optical input signal
(504) is transmitted to the optical switch output point 505. When the switch 500 is closed, the electromagnet 502 works and the movable part 60
5 moves, the optical input signal IN is cut off, and the optical input signal Im (306) is instead transmitted to the output point 505.

Figure 1114 shows how the optical output signal at the optical switch output point 605 of ItlillJ changes over time. In the figure, the optical input signals 1 and 8 are 2wL series with a pulse width To (seconds), and the amplitude value of Il is shown as being larger. Now, in FIG. 5, the moment when the switch 500 is closed, that is, the moment when the optical switch 501 starts operating, is indicated by number 400 in FIG. 1114.
From this time, the movable part of the optical switch (1113, Figure 503)
begins to move, so it reaches the light switch output point.
The magnitude of the signal decreases next INK and becomes zero after Tl (seconds). Then, during TI (seconds), neither of the two optical input signals enters the movable part 303, so no output signal appears. After that, when the movable part 303 moves further, the I'' signal appears at the next alK output point, and after Ts (seconds), the amplitude is approximately equal to the input ll signal (reduced by the loss due to the optical switch). The output signal will appear at the output point of the optical switch.The time T8' required for switching the optical switch is Ta'-Tl+Tg+T3 (seconds).
is given by

Normally, the switching time Ta' of such an optical switch varies by 4h depending on the mechanism of the switch, but is between several milliseconds and several tens of milliseconds. Therefore, if such an optical switch is used during data transmission on an optical data highway with a high transmission speed, a large amount of data will be lost. For example, Tl=2
No. 8-0, when the transmission rate (=1/To)3=10Mb/#, at least TI/TO=(2
X1 o ) x (10X10 ) = 2X10' bits of data are lost, causing data errors and loss of synchronization in all optical data stations after that optical switch.

Therefore, in conventional optical data highway systems, bypassing an optical data station (ie, switching an optical switch) during system operation must be avoided at all costs.

One way to remove such constraints is 'l'J'
(T.

The purpose of such a high-speed optical switch is to use an extremely high-speed optical switch such that I! This is not possible with a mechanical switch as shown in Figure 5.

High-speed optical switches that utilize the polarization properties of crystals have also been proposed, but they require high voltages of several tens of volts for control and have heavy losses, making them impractical.

The present invention has been made in view of the drawbacks of conventional optical data highway systems as described above, and it is therefore an object of the present invention to avoid bypass switching of any data station during operation of the system. A unique optical data station system that does not cause any loss of transmitted data and therefore does not adversely affect the operation of other optical data stations! Our goal is to provide the following.

In order to achieve the above object, a device according to the present invention includes an optical branching device that branches an optical input signal into two, an optical coupling device that combines the two optical input signals, and amplifies and regenerates one of the branched optical signals. An optical regenerative repeater inputs the optical output to the optical coupler, and the other optical signal is delayed so that the phase of the other optical input signal input to the optical coupler becomes almost sluggish. The main components are an optical delay device input to the optical coupling device and a power supply device that supplies the R11 source necessary for the optical regenerative repeater. The m-K optical regenerative repeater is an AGC1r111II that controls the output amplitude after optical/electrical conversion to a constant level.
! , an optical output adjustment circuit that controls the optical intensity f of the optical output signal after amplification and reproduction, and an ma device that controls the power supply device and the #i-order optical output adjustment circuit. In addition, the control device controls the control order of the power supply device and the optical output adjustment circuit,
Control is performed in a predetermined order, and the output of the optical output signal is further controlled by the optical output adjustment circuit, from a state of no output to a constant oscillation, or from a constant output amplitude to a state of no output. The present invention is characterized in that the time constant of the AGC circuit is made larger than the loop time constant of the AGC circuit.

Hereinafter, a preferred embodiment of the present invention will be explained in detail with reference to the drawings.

FIG. 11!5 is a block diagram showing an implementation of an optical data station device that implements the present invention.

In the optical data station device according to the present invention, one switch automatically connects the data station to the optical data highway together with one of the power sources of the p data station, and makes it possible to communicate with other data stations. ...It is configured so that it can be bypassed from Iway. At this time, the multiplexing/demultiplexing device at each data station is omitted in order to avoid complication of explanation in Figure 111!5, which does not interfere with the operation of the optical data highway system. sS diagram (in which reference number 500 is an optical data station device, 501
505 is an optical branching device that branches the optical input signal button 2 into two.
505 is an optical-to-electrical conversion circuit (Qtλ506 is an AGC that controls the output amplitude after optical-to-electrical conversion to a constant value);
07 is a discrimination circuit (DFC) that performs discrimination and reproduction; 508 is an electric/optical conversion circuit i1 (VO); 509 is an optical output signal 51;
A light output adjustment circuit (LOA) that controls the light intensity of 0, 51
1 is an optical coupling device that couples two optical input signals 510 and 512; 514 delays the other branched optical signal 515, and connects two input signals 510 and 5 to optical coupling device 511;
Optical delay device (2), 51, which makes the phase substantially equal to that of 12
6 is a power supply device (POW) that supplies the @flow'IIt source necessary for the optical regenerative repeater, 517. is the optical output adjustment circuit 509
and a control device that controls the power supply device 516, and 518 indicates a power source (usually a commercial AC 11 source) of the power supply device 1516, respectively.

When the control signal 519 from the control device @517 becomes "ON", the optical output adjustment circuit 509 starts the electrical/optical conversion circuit Jll 5
Upon receiving the optical output from 0B, it outputs an optical output signal 510 with a constant amplitude from a state where there was no optical output until then, and #! When the 111 Koji Shingin 519 is turned "OFF", it no longer outputs the optical output signal from the state in which it had been outputting the optical output signal 510 with a constant amplitude. The order and time interval of starting and stopping the operation of the power supply device t516 and controlling the light output of the light output adjustment circuit 509 are controlled by the control device 517 as follows. When starting the operation of the power supply device 516, first the power supply device f5
16 is started, and att+ is controlled so that the optical output signal 5E of the optical output adjustment circuit 509 is output after a predetermined fixed time (D1 seconds). Power supply a
When stopping the operation of the power supply device i 516, first, the light output signal 510 of the light output adjustment circuit 509 is controlled not to be outputted, and then the operation of the power supply device i 516 is controlled to stop.

The control device 517 is, for example, @6W! This can be realized with a configuration as shown in Q. In FIG. 6, reference number 601 is #! 5
A relay circuit for controlling the operation start and stop of the power supply 111514 shown in the figure, 602 a power supply device for operating this relay circuit 601 and the optical output adjustment circuit 509, 603 a power supply device 602 and the optical regeneration relay in FIG. 185 External ionization (
For example, a commercial AC power source), 604 is an optical output adjustment circuit 50
9 and the drive current of the relay circuit 601 are turned on'' and '''OF.
Switches 605 and 606 for F''' are used to predetermine the operation start times of the relay 1 path 601 and the optical power adjustment path 509, respectively, for a certain period of time po, 1.
)x (seconds), a terminal 607 supplies power to the power supply device 516 from the control circuit 517, and 608 supplies a control signal 519 from the control circuit 517 to operate the optical output adjustment circuit 509. The terminals shown in the figure below are for each terminal.

The delay circuits 605 and 606 shown in Figure 6 are realized, for example, by using an integrating circuit 703 and a comparator 704 with a configuration as shown in Figure 117. In the 117m delay circuit, terminal 701
The control signal supplied to the terminal 702 is delayed by a predetermined time (TDC seconds) and output to the terminal 702.

The operation of the optical data station according to the present invention will be explained below with reference to Fig. 5, Fig. 6, and Fig. 7. As mentioned above, the multiplexing/demultiplexing device that captures the signal addressed to the local station flowing on the optical data highway and handles the signal sent from the local station to the other station should be placed after the 15vA identification circuit 507. However, in the present invention, this is omitted for the sake of simplicity. The optical output amplitudes of the two optical input signals 510 and 512 input to the optical coupling device 511 of @f5vA are respectively IIL
, Ib, normal optical regenerative repeater fit 503
The amplitude of the optical output 510 identified and regenerated is considerably larger (Ia>>It), and if the optical regenerative repeater 506 is operating normally, it passes through the optical station. The main path for optical signals is the optical branching device 501 and the optical coupling device [
Between 1511 and 1511, the optical regenerative repeater 503 @ is used, and when the first optical regenerative repeater 503 is not operating, the optical delay *tsi4@ route is taken. Switching this route at the optical data stage simply turns the power supply line to the optical regenerative repeater 505 "ON'" and "OFF" L, which will generate an abnormal output during the transition and cause a transmission error. Nineteenth birthday,
According to the optical data station with the configuration shown in FIG. 5, the optical regenerative repeater 1it 503 does not operate sufficiently and some of the transmitted data is lost, which affects the operation of the optical data highway system. "ON", "OFF"
The impact on the optical data highway system caused by this can be avoided by the controller 517, and @6
WAf) xyyf604tD@ON”, @OFF”rif
Connecting or bypassing the f-t' optical system to the optical data highway can be accomplished by turning the power supply device 516 on and off. In order to realize switching of signal paths within the optical station without affecting the optical data highway system, the control device 517
The operation start and stop of the power supply device 516 and the optical output #s*
The order and time interval of light output control of the circuit 509 are controlled as follows. Its control alIIIa device 517
This is realized by adjusting the delay circuits 605 and 604 within. First, when connecting the optical data station to the optical data highway and making it possible to communicate with other data stations, first turn on the switch 604 and then immediately operate the relay circuit 601 to connect the terminal 607 to V.
L source is supplied to start the operation of the power supply device 516, and after a predetermined period of time (DX seconds), the terminal 6 is
08 to generate a control signal 519 to control the optical output adjustment circuit 50.
Control is performed so that the optical output signal No. 9 is output. As a result, the line optical delay device 51411 waits until the switch 604 is turned on.
The signal that was passing through is switched to take the route of the optical regenerative repeater 505@. In addition, when it is desired to bypass the data station from the optical data path 1, the switch 604 is turned "OFF" to first cut off the control signal 519 to the terminal 608 and the optical output signal 5 of the optical output adjustment circuit 509 is
10 is controlled so that it is no longer output, the relay circuit 6υ1 is operated to cut off the power supply to the terminal 607, and the operation of the power supply device @516 is controlled to be stopped. As a result, until the switch 604 is disconnected, the optical regenerative repeater 50
3. The signal that passed through ill was sent to the optical polishing device 514.
It switches to take the bypass route of Im. In this case, two optical input signals 510 and 51 to optical coupler 511
The phase with 2 is adjusted by the optical delay device 514 so that they are almost in the same phase, so that no loss or duplication of transmission data occurs before and after switching the signal path.

Next, a method of adjusting the delay circuits 605 and 606 will be explained below. Regarding the DoO value of 1I16FjA, the value DO when the switch 604 is changed from "OFF" to 1ON''
Set O to almost zero, and conversely turn switch 604 from "ON" to "
OFF", the value Do (IFF) is determined to be a sufficiently large constant value.
The value shown in 'JIJF' is sufficient. When the switch 604 in figure @6 is turned on, the 9th time is tos"a4 de, and the 9th time is if, the output voltage waveform of the switch 604 is @s W If it becomes as shown in (a), the integrating circuit in the delay circuit 605 (#I7, 705) (D output voltage waveform will become as shown in @8, 800 O. Therefore, the reference voltage of the comparator 704 is set as shown in FIG. If a small value like v'xxp is selected, the output voltage waveform of the comparator 705 and therefore the output voltage waveform of the delay circuit 605 will be as shown in Figure WJ8 (-
), 1) oos50, Do □FF >
It can be set to 0. [) Regarding the ripple of
”, Do()#<D1%, “OFF”, p
o opry > DX ), :! The reference voltage VJJF of the comparator 704 is as shown in FIG. The figure shows a case where the value of this reference voltage vsxy is set to F//2, which is half of the wax output voltage mE.

In this case, after Tfl (seconds) after the switch 604 is turned ON or OFF, the optical output adjustment circuit 509
A control signal is generated at terminal 702 to turn it ON'' or @OFF. Therefore, the value of TJ) is set to a time interval Dl that does not affect the operation of the optical data highway system even if the optical signal path is switched. (I vxx
It may be set by y. By the control device 517 using the delay circuits 605 and 606 set as above,
Optical data station 500 due to switching of optical signal path
The influence on the operation of the optical data highway system caused by turning the power supply device 516t-ON and OFF can be canceled.The optical output vI41F circuit 509 used here
receives the identified and regenerated optical output from the electrical/optical conversion circuit 508 and turns on the control signal 519 from the control device 1517.
” or “OFF”, the circuit that changes the optical output from a state where no optical output is output to a state where an optical output signal 510 of a constant amplitude is output, or vice versa, is the most (resourceful) circuit. ) An optical switch can be considered as a practical example.

This light switch is I! ! Generally, a mechanical switch such as 501 shown in FIG. 3 is used, and the transition time between a state in which no optical output is output and a state in which an optical output with a constant amplitude is output is determined by a time constant Tat. 901 in Fig. 99 represents the time change in the width of the optical output signal of the optical coupling device 511 when the optical output adjustment circuit 509 is controlled from a state where an optical output with a constant amplitude is output to no optical output. Nine things. Due to the state change of the optical output adjustment circuit, the output amplitude changes from the constant amplitude IIL after discrimination and reproduction to the amplitude IbK of the optical signal 512 bypassed by the optical delay device t 514 @. The time constant of this change is T1.

At this time, in the optical data station connected to the next stage of this optical data station, optical signal amplitude fluctuation occurs due to the optical signal path switching of the previous stage optical data station. In each optical data station, the AGC circuit 506 controls such fluctuations in the optical input signal so that the output amplitude after optical-to-electrical conversion is constant.In the present invention, the loop time constant of this AGC circuit is T is set to be smaller than the time constant T8 of the optical output adjustment circuit. If A
When the time constant Ti of the GC circuit is larger than the time constant TJ of the optical output adjustment circuit, the optical output is adjusted to 0% where the operation of AGc cannot follow the amplitude fluctuation of the optical input signal due to the time constant Ts of the optical output adjustment circuit 509. Since the amplitude suddenly decreases when the circuit 509 changes from a state where it outputs a constant amplitude to a state where no optical output is output, if the AGC circuit does not follow this amplitude fluctuation, the input If the amplitude is small, a phenomenon occurs in which the human input signal deviates from the optimal reference voltage, making normal regeneration relay impossible and affecting the operation of the optical data highway system.
It may cause

This phenomenon is due to the relationship between the time constants between the optical output adjustment circuit of one optical data station and the AGC circuit of the next stage optical data station, but normally optical data stages with the same configuration Since we use - optical output in the optical data station -! Time constant of one circuit TmuGC
By setting the relationship between the loop time constant Ti of the circuit and Ta>Ti, normal regenerative relay is always possible.

The time constants Ta and A of the optical output adjustment circuit are shown below using Figure 99.
GC circuit loop time constant TAo relationship-1) E Ta>T
In Figure 0, which explains that it must be i, the switch 604 is turned OFF and the optical output adjustment circuit 509 is controlled from a state where an optical output signal 510 of a constant amplitude is output to no optical output. The figure shows the amplitude of the optical output signal 513 of the optical feeder W1511 during the run.This optical output signal becomes the optical input signal to the next optical data stage.Now, the time constant relationship is Ti<C. Consider the case.The dashed line 902 in the figure
is the case when the time constant T*=Tiz, and indicates the limit value of the amplitude change that can be tracked by the AGC circuit, Tiz<T's
Then, in M, the circuit can sufficiently follow the amplitude fluctuation 901 of the optical input signal.Consider the case of ri>ra in the 0-order AGC when the time constant TA=Tix is indicated by the broken line 903 in the diagram.
A swing that can be followed by a circuit! If the optical input signal at this time is attenuated to a certain amplitude, which indicates the limit value of the change, the AGC circuit cannot catch up with this amplitude fluctuation until after a certain time delay.

As explained above, according to the optical data station device of the present invention, data transmission errors do not occur even if a certain data station is returned to its bypassed state at any point during data transmission. Therefore, there is no effect on the optical data station that is currently working, and, furthermore,
It is possible to disconnect and connect the optical data station with a single switch.
This is possible with "ON" and "OFF".Also, tIIS
The operating status of the optical regenerative repeater shown in the figure is constantly monitored, and when any abnormality is detected, the switch 6 shown in the figure 1116 is automatically activated.
By opening 04 (normally keeping it closed), an abnormality occurs in the optical regenerative repeater and automatic bypass of the optical data station becomes possible, thereby improving the reliability of the system.

When performing maintenance and inspection on the optical data station,
It is necessary to disconnect the optical data stage from the optical data highway without turning off the power to the optical data station. In this case, the switch 604 in Figure #16 is closed.
If the control signal 519 is set to 1 and then turned OFF, the optical data stage can be disconnected without affecting the operation of the optical data highway system.

In the above description, an optical switch using a mechanical switch was used as an example of the optical output adjustment circuit 509 shown in FIG. 11I15, but other implementation methods are also possible. This is a method of directly electrically controlling the optical output amplitude of the fluoroscopic element used in the electrical-to-optical conversion circuit 508 shown in FIG. 185. That is, the control signal 519 from the control unit [1517 is @ON], which determines the optical output amplitude of the optical element
In particular, when using a laser diode (LD) as a fluorophore, the threshold voltage should be controlled so that the optical output is generated only when
It is also possible to consider a control method that biases the optical output to a certain value so that the optical output is generated only when the control signal 519 turns "ON".The configuration in the case of 0 or more is as shown in Figure 5.
The optical conversion circuit 508 and the optical output adjustment circuit 509 are integrated. The optical output adjustment circuit according to any of these embodiments is included in the present invention, and does not change the essence of the present invention.

In addition, in explaining the AGC circuit 506 in FIG. 5, we have tried to explain the AGC circuit 506 by performing AGCt- on the electrical signal after optical-to-electrical conversion. However, when an avalanche photodiode is used as a light-receiving element, the bias voltage of the avalanche photodiode is controlled as an AGC loop, and the AGC using the electrical system described above is also used.
A C circuit can be considered. In this case, the configuration is such that the optical Φ-electric conversion circuit 505 and the island GC circuit 506 shown in Figure @5 are integrated. An AGC circuit using this method is also included in the present invention, and similarly does not change the essence of the present invention.

Although the present invention has been described above with respect to its preferred embodiments, these are merely illustrative, and it goes without saying that the present invention is not limited only to the embodiments disclosed herein.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a conventional optical data highway system, Fig. #I2 is a diagram showing a conventional bypass method in an optical data station, Fig. 5 is a diagram showing an example of an optical switch control method, Fig. 4 815 is a block diagram showing a configuration example for realizing the optical data station device of the present invention, and 11 to 6 are diagrams showing the constituent elements of the present invention. 117PltJ is a diagram showing an example of the configuration of a delay circuit used in the control device, and FIG. 8 is a diagram showing an example of the configuration of a delay circuit used in the control device. Figure 1119 is a diagram explaining the relationship between the amplitude fluctuation of the optical input signal, the time constant of the optical output adjustment circuit, and the time constant of the original circuit. 1.2.3 ・Optical data stage sensor, 4.5.6...
・Terminal, 7.8.9.10... Optical 7 Aipah transmission line, 1
1... Center station, 12... Bypass M
, 200... Optical data station, 2o1... Optical data signal, 202... Optical branching device, 203... Original switch, 2o4... Optical regenerative repeater, 205... Receiving unit, 2o6... - Transmission unit, 207... Multiplexing/demultiplexing device, 208... Terminal, 209.210. 211...
Contact, 300... Switch, 5o1... Optical switch, 3o2... Electromagnetic coil, 603... Movable part 1.
504.306... Optical input signal, 605... Optical switch output point, 400... Optical switch operation start point, 5
00... Optical data station, 501... Optical branching device, 502... Optical input signal, 503... Optical regenerative repeater, 504.515... Branched optical signal, 5o
5... Optical/electric conversion circuit, 506... AGC circuit,
507... Identification circuit, 508... Electrical/optical conversion circuit, 509... Optical output adjustment circuit, 511... Optical coupling device, 510.512... Optical signal to be coupled, 516...
... Optical output signal, 514 ... Optical delay wheel disc, 516 ...
- Power supply device, 517... Control device, 518... Power supply of power supply device, 5i9.520:... Control 41 Confucian No. 60
1... Relay circuit, +502... Power supply device, 605
...External power supply, 604...Switch, 605.60
6... Delay rotation, 607.608... Control signal output terminal, 701... Input terminal, 702... Output terminal,
70! I...Integrator circuit, 704...Comparator,
80011. Integral circuit. Output waveform, 901...Amplitude response characteristic of optical input signal, 902.90! ...Limit value of amplitude change that can be tracked when changing the time constant of the AGC circuit Patent applicant: NEC Corporation Representative Patent attorney Kuma #-Yutabe Figure 7 Figure 8

Claims (1)

[Claims] an optical branching device that branches an optical input signal into two; an optical coupling device that couples the two optical input signals; and an optical branching device that amplifies and regenerates one of the optical signals branched by the optical branching device and converts the optical output into the optical signal. an optical regenerative repeater that is input to the coupling device, and an optical signal that is branched by the optical branching device; The optical delay device that inputs the input to the optical coupling device, the power supply device that supplies the necessary current to the optical regenerative repeater #I, and the power supply device and the optical output adjustment circuit described below are controlled so as to AG comprising a control device and controlling the output amplitude after the lIJ optical regenerative repeater/electrical conversion to a constant level.
C circuit and an optical output adjustment circuit that controls the optical intensity of the optical output signal after the amplification and regeneration, and the control device
! Control between the power supply device described in A and the optical output adjustment circuit! n order, when starting the operation of the power supply device, first start the operation of the power supply device, and then after a certain period of time predetermined by the light output adjustment circuit, the light output is output from the optical regenerative repeater. In order to stop the operation of the power distribution device, the light output adjustment circuit first controls the light output so that it is no longer output from the light distribution regeneration repeater, and then adjusts the light output to a predetermined constant level. Control the operation of # distribution 11 device to stop after the time, lll1
The time constant from a state of no output to a constant amplitude of the optical output signal whose output is controlled by the output adjustment circuit, or from a constant output amplitude to a state of no output, is determined by the loop of the AGC circuit. An optical data station 7-day M setting characterized in that the time constant is larger than the time constant.