JPH03214936A - Monitoring signal transfer device for optical repeater - Google Patents

Abstract

PURPOSE:To prevent complicated system constitution by applying the wavelength multiplex of a monitoring signal light with a wavelength different from the wavelength of a main signal light to a main signal light. CONSTITUTION:This device is provided with a monitoring light source WL with a wavelength lambda1 capable of amplification at an optical amplifier AM and different from an optical wavelength lambda0 of the main signal light ms, a monitoring processing circuit WP monitoring an optical input state to the optical amplifier AM, or an optical output state of the relevant optical amplifier AM or the operating state of the relevant optical amplifier AM and applying optical amplitude modulation to the monitoring light source WL with a monitoring signal ws based on the monitoring information wi and a synthesizer CP applying wavelength multiplex an output light ams of the optical amplifier AM and a monitoring signal light wo by the light source WL.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a monitoring signal transfer device for an optical repeater that is applied to an optical transmission system using optical fibers.

(Prior art) In an optical transmission system, from the viewpoint of maintenance and operation, it is necessary to at least select a faulty section in an optical fiber transmission line and evaluate repeater failures, and to send this monitoring information as a monitoring signal to terminal equipment, etc. be.

Although a system that incorporates an optical amplifier using optical pumping into a monitoring system has not yet been established, an optical repeater using an optical amplifier can be thought of as an optical analog amplifier, so monitoring signals can be converted into digital mains. It is difficult to send digitally in addition to signals. Therefore, it is conceivable to send the monitoring signal using a separate line.

(Problems to be Solved by the Invention) As described above, a system for transferring a monitoring signal when an optically pumped optical amplifier is incorporated as an optical repeater in an optical transmission system has not yet been established. Furthermore, since the optical amplifier is an analog amplifier, it is difficult to add a monitoring signal based on monitoring information to the digital main signal and transmit it through the same optical fiber.

The present invention has been made in view of the above circumstances, and its purpose is to be able to transfer monitoring information through the same optical transmission path as the optical transmission path through which the main signal light is transmitted, and to connect optical repeaters in multiple stages. It is an object of the present invention to provide a monitoring signal transfer device for optical repeaters that can transfer monitoring information for each optical repeater through the same optical transmission line even when the optical repeaters are in use.

(Means for Solving the Problems) In order to achieve the above object, in claim (1), as shown in FIG. The optical wavelength λ of the main signal light ms is a wavelength that can be amplified by the amplifier AM. a monitoring light source WL having an oscillation wavelength λ1 different from λ1, and an optical amplifier AM.
The optical input state to the optical amplifier AM, the optical output state of the optical amplifier AM, or the operating state of the optical amplifier AM is monitored, and a monitoring light source WL is transmitted by a monitoring signal ws based on the monitoring information wi.
A monitoring processing circuit WP that performs optical amplitude modulation on the optical signal, and a multiplexer CP that wavelength-multiplexes the output light ams of the optical amplifier AM and the monitoring signal light WO from the monitoring light source WL are provided.

Moreover, in claim (2), as shown in FIG. The oscillation wavelengths of are set to different wavelengths λ1 to λ. It was set to Further, the symbol FB in the figure indicates a transmission line optical fiber.

Further, in claim (3), as shown in FIG. The oscillation wavelengths of all the stages are set to the same wavelength λ1, and the monitoring signals ws from the monitoring processing circuit WP in each stage section have different frequencies f1 to fn, respectively.

Further, in claim (4), as shown in FIG.
In an optical repeater monitoring signal transfer device equipped with an optical amplifier AM that amplifies s, the optical input state to the optical amplifier AM, the optical output state of the optical amplifier AM, or the optical amplifier AM
A monitoring processing circuit wp is provided which monitors the operating state of the pump and modulates the optical amplitude of the excitation light source PS using a monitoring signal ws based on the monitoring information wi.

Furthermore, in claim (5), as shown in FIG. The monitoring signals ws are configured to have different frequencies f1 to fo, respectively.

Further, in claim (6), as shown in FIG.
In an optical repeater monitoring signal transfer device equipped with an optical amplifier AM that amplifies s, the optical input state to the optical amplifier AM, the optical output state of the optical amplifier AM, or the optical amplifier AM
A monitoring processing circuit WP that monitors the operating state of the pump and modulates the optical amplitude of the pumping light source PS using a monitoring signal ws based on the monitoring information wi, a branching device DV that branches the pumping light pm from the pumping light source PS, and a branching device DV. A multiplexer CP that wavelength-multiplexes the branched light clQ and the output light ams of the optical amplifier AM.
and has been established.

(for production) According to the apparatus shown in FIG. 1, the optical wavelength λ input to the optical repeater.

The main signal light ms is optically amplified by an optical amplifier AM and has a wavelength λ. is output as main signal light ams.

In parallel with this, the monitoring processing circuit WP monitors the optical input state to the optical amplifier AM or the optical amplifier A.
Monitoring information wi such as the optical output state of M or the operating state of the optical amplifier AM, specifically, the optical input disconnection due to the optical fiber FB disconnection or a repeater failure from the optical amplifier AM, is obtained.

The monitoring processing circuit WP outputs a monitoring signal ws based on the monitoring information wi to the monitoring light source WL, and amplitude modulates the monitoring light source WL.

Accordingly, the amplitude-modulated monitoring signal light wo is output from the monitoring light source WL having the oscillation wavelength λ1.

This monitoring signal light wo is input to the multiplexer CP, where it is wavelength-multiplexed with the output light (main signal light) ams of the optical amplifier AM, and this wavelength-multiplexed light is output as the output light of the optical repeater.

Further, according to the apparatus shown in FIG. 2, the optical signal input to the first-stage optical repeater has a wavelength λ. The main signal light is ms. This main signal light ms is optically amplified by an optical amplifier AM, and has a wavelength λ.

is output as main signal light ams.

On the other hand, the monitoring light source WLe having the oscillation wavelength λ1 is amplitude-modulated by the monitoring signal ws from the monitoring processing circuit WP1 that performs processing based on the above-mentioned monitoring information wi. Based on this, the supervisory signal light wo (λ,) is sent to the main signal light a by the multiplexer CP1.
ms and is wavelength-multiplexed and sent to the optical fiber transmission line FB.

The signal light ms2 input to the second-stage optical repeater has a wavelength λ.

The main signal light ms and the monitoring signal light wo of wavelength λ1 inserted by the first-stage optical repeater are both amplified by the optical amplifier AM2. Also, similar to the first-stage optical repeater, the monitoring light source WL2 of the oscillation wavelength λ2 in the second-stage optical repeater is amplitude-modulated by the monitoring signal w s 2, and its output light, the monitoring signal light wo(λ2), is amplitude-modulated by the monitoring signal w s 2. , wavelength multiplexed with the output signal light a m s 2 of the optical amplifier AM2 by the multiplexer CP2.

Therefore, the wavelength λ is transmitted from the second stage optical repeater. main signal light m
Monitoring signal light wo having wavelengths λ1 and λ2 is output.

The same operation as above is performed up to the n-stage optical repeater, and from the n-th stage optical repeater, the wavelength λ is transmitted. main signal light ms and wavelength λ1~
λ. A signal light cs obtained by multiplexing the monitoring signal light wo is output.

In a wavelength demultiplexer WD in a terminal unit that terminates a monitoring signal, such as a terminal station device or an optical repeater, the wavelength λ is used. main signal light ms and wavelengths λ1 to λ. The monitoring signal light WO is demultiplexed. Monitoring of each optical repeater is performed by extracting the monitoring signal light WO of the corresponding optical repeater.

Further, according to the apparatus shown in FIG. 3, the optical signal input to the first-stage optical repeater has a wavelength λ. The main signal light is ms. This main signal light ms is optically amplified by an optical amplifier AM, and the wavelength λ
. is output as signal light ams.

On the other hand, the monitoring light source WL, with the oscillation wavelength λ1 in the first-stage optical repeater, is amplitude-modulated by the monitoring signal ws(f,) of the frequency f1 by the monitoring processing circuit WP1, and its output light is the monitoring signal light wo(λ1, f1) is the wavelength λ output from the optical amplifier AMI by the multiplexer CP. main signal light arns
wavelength multiplexed.

The signal light ms2 input to the second-stage optical repeater is the main signal light ms and the supervisory signal light wo inserted by the first-stage optical repeater, and is amplified together by the optical amplifier AM2. Laser wavelength λ1
The monitoring light source WL2 is amplitude-modulated by a monitoring signal ws (f2) having a frequency f2 based on the monitoring information wi by the monitoring processing circuit WP2, and its output light is the monitoring signal light WO (λ1
．． f2") is multiplexed with the output signal light a m s 2 of the optical amplifier AM2 by the multiplexer CP2. Therefore, from the second stage optical repeater, the main signal light ms of wavelength λ.
The monitoring signal light wo having components of frequencies f, , f2 is output.

The same operation as above is performed up to the n-stage optical repeater, and from the n-th stage optical repeater, the wavelength λ is transmitted. With main signal light ms and wavelength λ1, frequency components f1 to f. A signal light cs obtained by multiplexing the monitoring signal lights WO is output.

In a termination unit that terminates a monitoring signal, for example, a wavelength demultiplexer in a terminal equipment or an optical repeater, the wavelength λ. main signal light m
s and wavelength λ1, frequency components fe~f. monitoring signal light wo
is demultiplexed. Monitoring of each optical repeater is performed by separating the frequency components of the monitoring signal light wo of the corresponding optical repeater.

Furthermore, according to the apparatus shown in FIG. 4, the pumping light source PS for exciting the optical amplifier AM is amplitude-modulated by the monitoring signal ws from the monitoring processing circuit WP, which performs processing based on the above-mentioned monitoring information wi. Ru.

At this time, the monitoring signal ws is set to, for example, a signal with a very low frequency compared to the time constant of the excitation light pm.

The amplification factor of the optical amplifier AM changes according to the monitoring signal ws. Therefore, as shown in FIG. 4(b), the main signal light ms input to the optical repeater becomes an output signal light ems which is further amplified and subjected to so-called envelope modulation.

In this case, each optical repeater is monitored by extracting the frequency component of the envelope-modulated signal light e m s at the terminal device or repeater that terminates the monitoring signal.

Further, according to the apparatus shown in FIG. 5, the excitation light source of each optical repeater has a frequency f1 to f which is unique to each optical repeater so that it can be identified.
It is amplitude modulated with the supervisory signal ws having zero. Therefore n
The optical signal that passes through the optical repeater in the second stage and is input to the end station device or optical repeater that terminates the monitoring signal is the main signal light ms,
The signal emS is envelope-modulated at frequencies f1 to fn specific to each optical repeater. Monitoring of each optical repeater is performed by extracting these frequency components f1 to fn.

Further, according to the apparatus shown in FIG. 6, the pumping light p with the wavelength λ1 output from the pumping light source PS for pumping the optical amplifier AM
m is amplitude-modulated by a monitoring signal ws from a monitoring processing circuit WP that performs processing based on the above-mentioned monitoring information wi.

At this time, the monitoring signal ws is set to, for example, a signal with a sufficiently faster period than the time constant of the pumping light pm. This allows the intensity of the pumping light of the optical amplifier AM to be considered constant.

Further, the pumping light pm with wavelength λ1 from the pumping light source PS is branched by a splitter DV and inputted to the optical amplifier AM, while one branched light d and Q is sent to the multiplexer C as the monitoring signal light wo.
It is input to P. This results in an amplified wavelength λ. The main signal light ms and the supervisory signal light wo having a wavelength λ1 are combined by a multiplexer CP and output.

At the next stage terminal equipment or repeater, the main signal light m
The optical repeater is monitored by passing the monitoring signal light wo and the monitoring signal light wo, and processing the monitoring signal light wo.

(Embodiment) FIG. 7 is a block diagram showing a first embodiment of an optical repeater monitoring signal transfer device according to the present invention adopted in an optical fiber transmission system, and shows the configuration of FIG. 2 described above. As shown in FIG. 1, when n (n=1.2,...) stages of the devices shown in
) is extracted and illustrated.

In Fig. 1, PSm is a pumping light source, DVm is a splitter,
CP I. ．． is the input side multiplexer, AM is the optical amplifier, Is
, n is the optical isolator, and FLm is the wavelength. Ruta, wp.
n is a monitoring processing circuit, WLm is a monitoring light source, cpoffi
is an output side multiplexer, and FB is an optical fiber transmission line.

The excitation light source ps,,, has a predetermined oscillation wavelength, for example 1.4
8 μm band semiconductor laser PB, . , a and its drive circuit PS2b, and outputs excitation light pm of a predetermined intensity.

The splitter DV, . . . branches the input signal light (wavelength is in the 1.5 μm band for reasons to be described later) ms, n to the optical repeater into two, which has propagated through the optical fiber transmission line FB.

The multiplexer CPIm separates one of the branched lights (input signal light ms, .) branched by the splitter Dvm and the pumping light source PS. The excitation light pm generated by n is combined with the excitation light pm.

Optical amplifier AM. is composed of an optical fiber doped with a rare earth element such as erbium (Er) at a predetermined concentration, and a multiplexer CP I. , the input signal light ms. n,
It is amplified by an amplification effect based on the pumping light pm combined with this.

The amplification characteristics of the optical amplifier AM,n made of this Er-doped optical fiber have two peaks near wavelengths of 1.55 μm and 1.535 μm. For this reason, in this system,
For example, 1.55 μm is the wavelength λ of the main signal light ms. The wavelength λ. of the monitoring signal light wo is set near 1.535 μm. It is used as a seal.

Optical isolator Is. ．． , are arranged on the output end side of the optical amplifier AMm, and the optical amplifier AM. ．． , and an optical amplifier AM.

Prevents return light from entering.

The wavelength filters FL, . . . are optical isolators IS. Among the output lights of the optical isolator S0, the main signal light ms has a wavelength of 1.55 μm and the monitoring signal light WO
The wavelength band including the wavelength of around 1.535 μm is passed, and other wavelength bands, specifically, the wavelength 1.4 μm of the excitation light pm are passed.
Blocks the 8 μm band, etc.

The monitoring processing circuit wp,, is connected to the turnout Dv. The other branched light of n (input signal light ms, n) is input as monitoring information wi, and a monitoring signal ws corresponding to this input state, for example, a cutoff of optical input due to a breakage of the optical fiber transmission path, etc. is output to the monitoring light source WLm. Then, the monitoring light source WL. Amplitude modulate n.

? The viewing light source WL,n is a unique oscillation wavelength λ■ for each optical repeater, in this example, 1.535+△λX (m1)μ
A semiconductor laser WL. na and its drive circuit W
L,. , b, and outputs a supervisory signal light wo whose amplitude is modulated according to the input of the supervisory signal ws.

The multiplexer cpo receives the amplified signal light ams that has passed through the wavelength filter FLm. and monitoring light source WL. The monitoring signal light wo is wavelength-multiplexed.

Next, the operation of the above configuration will be explained.

First, the signal light mS0 input to the m-th optical repeater is the main signal light ms with a wavelength of 1.55 μm and the wavelength 1.535 ttmS inserted at each stage from the first stage to the (m-1)th stage.
1.535+Δλ, 1.535+Δλx
(m-2) μm supervisory signal light wo, splitter DV
, n.

Turnout DV. One signal light m s m
is the multiplexer CPI. , , and the other signal light ms.
．． , is input to the monitoring processing circuit wp as monitoring information wi.

Multiplexer CP I,. , together with the signal light ms,n,
Pumping light pm from the pumping light source PSm is input, and signal light m
s Ill and excitation light pm are combined. This multiplexer C
P.I. The multiplexed light by n is input to optical amplification AMm.

Optical amplifier AM. Of the multiplexed light input to n, the pumping light p
As described above, the wavelength range (1.48 μm band) matching the absorption band of Er is used as m. For this reason,
Er atoms, which are additives to the optical fiber, are excited by the excitation light pm, and with an amplification degree based on this, the signal light m
s, is amplified.

The amplified signal light m s m and the pumping light pm subjected to the amplification action are supplied to an optical amplifier AM. After outputting the optical isolator Is
, n and is input to the wavelength filters FL, , . Wavelength filter FL. , , unnecessary excitation light and spontaneous emission light that becomes noise are removed, and the amplified signal light ms
．． , only passes through here and is input to the multiplexer cpo, ,.

On the other hand, in the monitoring processing circuit WP,n, the input monitoring information w
A monitoring signal ws based on i is generated, and this monitoring signal w
s is output to the drive circuit WLmb of the monitoring light source WLm.

Drive circuit WL. nb responds to the input of the monitoring signal ws,
The semiconductor laser WLma is caused to oscillate. As a result, the monitoring light source WI. , the wavelength 1.535 has a waveform pattern according to the input state of the signal light m s m to the optical repeater.
A monitoring signal light wo of μm+ΔλX(m-1) μm is output.

This monitoring signal light wo is input to a multiplexer CPOm, and the amplified signal light ms. This wavelength-multiplexed light is sent to the next stage optical fiber transmission line FB as the output light csm of the m-th optical repeater.

The above two operations are performed up to the n-stage optical repeater, and from the n-th stage optical repeater, the main signal light ms with a wavelength of 1.55 μm, wavelengths of 1.535 μm, 1.535+Δλ, . . . ...
A signal light obtained by combining the monitoring signal light wo of 1.535+Δλx(n-1) μm is output.

The main signal light ms and the monitoring signal light w transmitted in this way
Does the signal light consisting of o terminate the monitoring signal? The signal is demultiplexed by a wavelength demultiplexer (not shown) in a termination section, for example, a terminal station or an optical repeater. Thereby, monitoring of each optical repeater is performed by extracting the monitoring signal light wo of the corresponding optical repeater.

As explained above, according to the first embodiment, the wavelength λ of the main signal light ms. (=1.535μm) and a different wavelength λ
Since the monitoring signal light of m (=1.535+Δλx(m-1)) is wavelength-multiplexed with the main signal light, the monitoring signal light wo can be transmitted along with the main signal light ms through the same optical fiber without installing a separate line. It is possible to transfer the information using the route FB, which prevents the system configuration from becoming complicated.

In addition, the oscillation wavelength of the monitoring light source WL■ in each step section is
Since each wavelength is set to be different, even when optical repeaters are connected in multiple stages, it is possible to transmit through the same optical fiber transmission line FB, and the failure status at each stage can be accurately determined and understood using a termination device, etc. .

Also, since an optical isolator ISm is placed at the output end of the optical amplifier, what is the return light to this output end? This allows the optical amplifier AM. oscillation of n can be prevented.

Furthermore, since the wavelength filter FLm is arranged on the optical output side of the optical isolator Is, unnecessary excitation light pm and spontaneous emission light can be removed, and a good communication system can be realized.

In the first embodiment, the optical amplifier AM. Signal light msm to n
The input state of the optical amplifier AM, or the pumping light source p
s. , may be configured to monitor the operating state of, etc., and adopt it as the monitoring information wi.

FIG. 8 is a configuration diagram showing a second embodiment of the optical repeater supervisory signal transfer device according to the present invention.

In the second embodiment, the first embodiment is modified so that each optical repeater in each stage is given a unique wavelength as the oscillation wavelength of the monitoring light source WL, so that each optical repeater can be identified. In contrast to the above configuration, the WI. The oscillation wavelengths of the monitoring processing circuits WP. and WP. The monitoring signal ws by n has a unique frequency fm for each optical repeater, and this natural frequency f
, n, the monitoring light sources WL, . is amplitude modulated, and the frequency components of each monitoring signal light wo are used to
It is configured to identify each optical repeater.

Even in such a configuration, the same effects as in the first embodiment can be obtained.

FIG. 9 is a configuration diagram showing a third embodiment of the optical repeater monitoring signal transfer device according to the present invention.

In the third embodiment, an optical amplifier made of an Er-doped optical fiber has a configuration that takes advantage of the fact that the amplification factor changes by increasing or decreasing the amount of pumping light pm.

That is, the monitoring signal ws from the monitoring processing circuit WL is given a predetermined frequency f, and the monitoring signal ws is used to control the excitation light source PS.
is configured to amplitude modulate. Therefore, in this embodiment, the excitation light source WL and the output-side multiplexer CPO in the first and second embodiments are unnecessary, and the configuration is simplified.

In this configuration, the frequency f of the monitoring signal ws that amplitude-modulates the pump light source PS is 10
It is set below kHz. This allows optical (fiber)
The amplification factor of the amplifier AM changes with the frequency f that amplitude-modulates the pumping light source PS, and the amplified signal light is accordingly envelope-modulated.

The optical repeater is monitored by extracting the frequency component of the envelope of the amplified signal light modulated in this manner in a terminal equipment (not shown) or the like.

In addition, when the apparatus shown in FIG. 9 is connected in multiple stages (for example, n stages), a monitoring signal ws for amplitude modulating the excitation light source PS is used.
The frequency of f1 is set to a unique frequency f1 according to the optical repeater at each stage.
By assigning ~fn, each optical repeater can be identified.

FIG. 10 is a configuration diagram showing a fourth embodiment of an optical repeater monitoring signal transfer device according to the present invention.

The fourth embodiment differs from the third embodiment in that the so-called leakage pumping light output from the optical amplifier AM is used as it is as the monitoring signal light.

As a result, the wavelength filter FL is excluded from the configuration of the third embodiment (FIG. 9).

In addition, in this case, the frequency of the monitoring signal ws that amplitude-modulates the pumping light source PS is a high-period frequency (
Mflz). This allows the optical amplifier AM
The amplification factor becomes constant.

Even in such a configuration, the same effects as in the third embodiment can be obtained.

FIG. 11 is a configuration diagram showing a fifth embodiment of the optical repeater supervisory signal transfer device according to the present invention.

The fifth embodiment differs from the fourth embodiment in that the pumping light pm, which is not subjected to pre-amplification, is directly used as the monitoring signal light, so the pumping light pm is wavelength-multiplexed on the amplified signal light ams. This is because it is configured like this.

Therefore, a splitter PDV that splits the pumping light pm into two is provided between the pumping light source PS and the multiplexer CPI, and a wavelength filter FL that blocks the pumping light wavelength is provided on the output side of the optical isolator IS. A multiplexer CPO is provided which wavelength-multiplexes the amplified signal light ams that has passed through the filter FL and the branched pumping light dpm as the monitoring signal light WO.

Even in such a configuration, the same effects as in the third embodiment can be obtained.

(Effects of the Invention) As explained above, according to claim (1), the monitoring signal light having a wavelength different from the wavelength of the main signal light can be wavelength-multiplexed on the main signal light. The supervisory signal light can be transferred along with the main signal light through the same transmission path without providing a separate line, and as a result, it is possible to prevent the system configuration from becoming complicated.

Furthermore, according to claim (2) or claim (3), since the oscillation wavelength of the monitoring light source or the frequency of the monitoring signal in each step section is set to a different wavelength or frequency,
Even when optical repeaters are connected in multiple stages, the main signal light and multiple monitoring signal lights can be transferred through the same transmission path, and it is also possible to accurately determine and identify broken sections of optical fibers and faulty optical repeaters. can.

Furthermore, according to claim (4) or claim (6), in addition to the effect of claim (1), the device configuration can be simplified. Furthermore, the effect is remarkable in claim (4).

Similarly, in claim (5), in addition to the effects of claim (3), the device configuration can be simplified.

[Brief explanation of drawings]

Figure 1 is a diagram corresponding to claim (1), Figure 2 is claim (2)
3 is a correspondence diagram of claim (3), FIG. 4 is a correspondence diagram of claim (4), FIG. 5 is a correspondence diagram of claim (5),
FIG. 6 is a diagram corresponding to claim (6), FIG. 7 is a block diagram showing a first embodiment of the optical repeater monitoring signal transfer device according to the present invention, and FIG. 8 is an optical repeater according to the present invention. FIG. 9 is a block diagram showing a third embodiment of the optical repeater monitoring signal transfer device according to the present invention, and FIG. 10 is a block diagram showing a third embodiment of the optical repeater monitoring signal transfer device according to the present invention. FIG. 11 is a block diagram showing a fourth embodiment of the optical repeater monitoring signal transfer device according to the present invention, and FIG. 11 is a block diagram showing a fifth embodiment of the optical repeater according to the present invention. In the figure, PS...pumping light source, DV, PDV...brancher, CP, CPI, CPO...multiplexer, AM...optical amplifier, Is...optical isolator, FL...wavelength Filter, WP...monitoring processing circuit, WL...monitoring light source, ms...main signal light, wi...monitoring information, ws...
- Monitoring signal, WO... Monitoring signal light.

Claims (6)

[Claims] (1) A monitoring signal transfer device for an optical repeater equipped with an optical amplifier using optical pumping, comprising: a monitoring light source having an oscillation wavelength that can be amplified by the optical amplifier and that is different from the optical wavelength of the main signal light; a monitoring processing circuit that monitors an optical input state to an optical amplifier, an optical output state of the optical amplifier, or an operating state of the optical amplifier, and modulates the optical amplitude of the monitoring light source with a monitoring signal based on the monitoring information; A monitoring signal transfer device for an optical repeater, comprising a multiplexer that wavelength-multiplexes the output light of the amplifier and the monitoring signal light from the monitoring light source. (2) Monitoring of an optical repeater characterized in that the optical repeater monitoring signal transfer device according to claim (1) is connected in multiple stages, and the oscillation wavelength of the monitoring light source in each stage is set to a different wavelength. Signal transfer device. (3) The optical repeater monitoring signal transfer device according to claim (1) is connected in multiple stages, and the oscillation wavelengths of the monitoring light sources in each stage are all set to the same wavelength, and the monitoring processing circuit in each stage is 1. A monitoring signal transfer device for an optical repeater, characterized in that each monitoring signal has a different frequency. (4) In an optical repeater monitoring signal transfer device equipped with an optical amplifier that amplifies input signal light based on input of pumping light from a pumping light source, the optical input state to the optical amplifier or the optical output state of the optical amplifier. Alternatively, a monitoring signal transfer device for an optical repeater, comprising a monitoring processing circuit that monitors the operating state of the optical amplifier and modulates the optical amplitude of the excitation light source using a monitoring signal based on the monitoring information. (5) An optical repeater characterized in that the optical repeater monitoring signal transfer device according to claim (4) is connected in multiple stages, and the monitoring signals from the monitoring processing circuit in each stage have different frequencies. supervisory signal transfer device. (6) In an optical repeater monitoring signal transfer device equipped with an optical amplifier that amplifies input signal light based on input of pumping light from a pumping light source, the optical input state to the optical amplifier or the optical output state of the optical amplifier. or a monitoring processing circuit that monitors the operating state of the optical amplifier and modulates the optical amplitude of the pumping light source using a monitoring signal based on the monitoring information; a branching device that branches the pumping light from the pumping light source; 1. A monitoring signal transfer device for an optical repeater, comprising a multiplexer that wavelength-multiplexes one branched light and the output light of the optical amplifier.