JPH11136712A - Wavelength multiplex optical repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease an optical loss in a node and to suppress a stimulated optical output to circuits succeeding an erbium doped optical fiber amplifier EDFA gate switch. SOLUTION: A signal light outputted to an optical transmission line 131 is outputted to a gate optical amplifier 51 by a branching function of a wavelength multiplex optical branching device 151. The signal light amplified by the gate optical amplifier 151 is given to a wavelength multiplex branching device 152, from which the signal is outputted to an optical transmission line 132 by its wave synthesis function. Then the signal is multiplexed with other wavelength light by an optical multiplexer/ demultiplexer 410 and outputted to an optical transmission line 120. The signal light from the transmission line 131 is branched by an optical branching device 31 and fed to an optical receiver 71. With the optical signal inserted, the gate optical amplifier 51 is turned off, and the signal light outputted from an optical transmitter 81 is sent to the optical transmission line 132 via the optical branching device 41 and outputted to the optical transmission line 1209 via the optical multiplexer/demultiplexer 410. Wavelength multiplex optical branching devices 151-154 apply optical multiplexing/ demultiplexing to a light of a different wavelength with a low loss. The loss is reduced by 5dB or more in comparison with the case of using one-to-one optical branching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplexing optical repeater / amplifier for performing wavelength division multiplexing optical add / drop and optical amplification in optical communication and optical switching.

[0002]

2. Description of the Related Art A wavelength division multiplexing system for transmitting signal lights having different wavelengths in a single optical fiber enables a large-capacity optical transmission, a high gain represented by an EDFA (erbium-doped optical fiber amplifier), and the like. The emergence of high-output optical amplifiers has enabled long-distance, large-capacity optical transmission between fibers.
When relaying and amplifying a signal, ADM (add / drop multiplexing), which adds and drops a signal at the relay station, can establish a denser network.

[0003] In particular, an optical ADM in which signal light is added and dropped without converting the signal light into an electric signal can be reduced in the size of a relay station and is independent of the communication speed and format. In addition, it is possible to cope with a change in the communication mode by replacing the interface, which greatly contributes to a reduction in communication cost.

As one form of optical ADM, a wavelength division multiplexed light is demultiplexed in a node, signal processing for optical addition and dropping is performed for each wavelength, multiplexed into the wavelength division multiplexed light again, and output to the next node. There is an insertion (wavelength ADM) device. this is,
The feature is that optical add / drop of all the maximum wavelengths is possible at one node. Therefore, in addition to the above advantages, it is possible to switch the signal path in accordance with a change in service demand without making a new capital investment.

FIG. 15 shows a prior art wavelength division multiplexing optical repeater / amplifier configured to perform the functions of demultiplexing and multiplexing with a single optical demultiplexer and perform amplification, insertion and branching for each wavelength. It shows the technology. In FIG. 15, for example, wavelengths of 1530 nm, 1540 nm, 155
Four signal lights of 0 nm and 1560 nm are wavelength-multiplexed. These lights are input to an optical multiplexer / demultiplexer 410 typified by an arrayed waveguide diffraction grating and output to different optical transmission paths 131 to 134, respectively.

The operation of passing, dropping, and inserting in the operation of the wavelength ADM will be described with reference to FIG. Regarding the passage, 1530n output to the optical transmission line 131
After the signal light of m is optically amplified by the gate type optical amplifier 51,
After passing through the optical isolator 91, the optical branch 12 having a branch ratio of 1: 1
The optical signal is returned to the optical multiplexer / demultiplexer 410 via the optical transmission line 132 connected by the optical multiplexer / demultiplexer 410, remultiplexed by the optical multiplexer / demultiplexer 410, and output to the optical transmission line 120. For the branch, transmission line 1
The signal light of 1530 nm output to 31 is input to the optical receiver 71 connected to the optical branch 31 and received.

As for the insertion, the signal light of 1530 nm output to the transmission line 131 is output from the gate type optical amplifier 51.
Is turned off, the output from the optical amplifier is cut off. Then, 1530 nm output from the optical transmitter 81
Is connected to the optical transmission line 132 by the optical branch 41 and is input to the optical multiplexer / demultiplexer 410.

Optical transmission lines 132-1 through which light of other wavelengths flows
34 is also connected to the optical multiplexer / demultiplexer 410 through the same configuration and output to the optical transmission line 120. As described above, it is possible to amplify, drop, and insert an optical signal of an arbitrary wavelength in the node.

[0009]

The functions of demultiplexing and multiplexing shown in FIG. 15 are performed by a single optical demultiplexer, which performs add / drop for each wavelength and amplifies the passing signal light. The wavelength-division multiplexing optical amplifying device having the configuration of looping back and folding back has an advantage that the number of optical components and control items can be reduced, so that low-cost and high-density component mounting is possible.

However, in this configuration, in addition to the optical branches 31 to 34 and 41 to 44 for adding and dropping the signal light, the optical branches 11 to 11 for connecting the transmission paths for each wavelength are provided.
When an optical signal reciprocates in a node, the optical signal passes through two additional optical branches in addition to the optical branch for adding and dropping.

When the branching ratio of the optical branches 11 to 14 is 1: 1, the insertion loss due to the two optical branches is 6 dB. In the wavelength division multiplexing optical add / drop multiplexer, since the insertion loss of the optical add / drop multiplexer and the optical multiplexer / demultiplexer is expected, the degree of freedom in designing the optical level in the node is limited. In order to prevent the limitation of the optical level, there is a method of appropriately installing an optical amplifier in addition to the method of reducing the loss of the optical component in the node.

An erbium-doped fiber is controlled with pumping light (pumping light input) as a gate switch for adding / dropping a signal in a wavelength division multiplexing optical add / drop multiplexer and as an optical amplifier for transmitting signal light to a next node. Sometimes, the signal light is amplified and passed through the EDF, and when no pump light is input, the signal light is absorbed in the EDF.) A gate for the signal light and an EDFA gate for optical amplification can be used.

When this EDFA gate is used for compensating for optical loss due to the above-mentioned folded structure, it is necessary to increase the pumping light intensity when the transmission distance to the next node is long. Excitation light that has not been absorbed by the erbium-doped fiber when the gate is in the ON state is directly input to the optical multiplexer, and there is a high possibility that the optical components will be damaged. Therefore, when the number of multiplexed wavelengths is large, it is necessary to limit the intensity of the pumping light output from the pumping light source, and as a result, there is a problem that the possible transmission distance between nodes becomes short.

The present invention has been made in view of the above-mentioned problems of the prior art, and reduces the optical loss in a node and suppresses the leakage of pumping light output to the rear of an EDFA gate switch, thereby enabling transmission between nodes. The purpose is to increase the distance.

[0015]

In each of the optical transmission lines 131 to 134 in FIG. 15, the wavelength of the passing signal light is different between the forward path and the return path. The present invention focuses on this point, and considers each optical transmission line 1
An element having an optical multiplexing / demultiplexing function is used as each of the optical branches 11 to 14 for connecting the components 31 to 134. By introducing an element having an optical multiplexing / demultiplexing function, insertion loss due to the optical branches 11 to 14 can be reduced.

Further, according to the present invention, another element having a light demultiplexing function is provided behind the erbium-doped optical fiber, and the pump light is separated into the pump light so that the pump light is input to the optical multiplexer for wavelength multiplexing. It is characterized by not being done.
By this method, high-level excitation light is not input to the optical multiplexer, so that optical damage to the optical multiplexer can be prevented. Further, since a pumping light source having a large pumping light intensity can be employed, a longer transmission distance between nodes can be realized.

FIG. 2 is a diagram showing a configuration example of a wavelength division multiplexing optical branch (element having an optical multiplexing / demultiplexing function) used in the present invention. The wavelength division multiplexing optical branch 151 shown in FIG.
This is an example in the case of having a function of demultiplexing or combining light of 540 nm and wavelength of 1550 nm, and has a connection portion with optical fibers of optical input / output 1-3. The wavelength multiplexed light having the wavelength of 1540 nm and the wavelength of 1550 nm input to the optical input 1 is optically demultiplexed by the wavelength multiplexing optical branch 151, and
The wavelength of 1550 nm is input to the optical input / output 3, and the wavelength of
nm light is output. Each crosstalk has a characteristic of 15 dB or less and an insertion loss of 0.5 dB or less. Also, at the time of optical multiplexing, optical multiplexing can be performed with the same characteristics.

[0018]

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, the optical transmission line 110 has wavelengths of 1530 nm, 1540 nm, 1550 nm,
Four signal lights of 1560 nm are wavelength-multiplexed. These signal lights are input to an optical multiplexer / demultiplexer 410 typified by an arrayed waveguide diffraction grating, and different optical transmission paths 1
31 to 134. That is, the optical transmission path 131
There is only one wavelength of light in each of ~ 134.

The passing, dropping, and insertion in the operation of the wavelength ADM will be described below. First, for the passage,
The 1530 nm signal light output to the optical transmission line 131 is output to the gated optical amplifier 51 by the demultiplexing function of the wavelength division multiplexing optical branch 151. The signal light optically amplified by the gate type optical amplifier 51 is input to the wavelength division multiplexing optical branch 152 via the optical isolator 91, and is output to the optical transmission line 132 by the multiplexing function of the wavelength division multiplexing optical branch 152. And the optical demultiplexer 4
At 10, the light is multiplexed with other wavelength light and output to the optical transmission line 120.

Regarding the branch, the signal light of 1530 nm output to the transmission line 131 is input to the optical receiver 71 connected to the optical branch 31 and received. In addition, at the time of insertion, the signal light of 1530 nm output to the transmission line 131 shuts off the output from the optical gate by turning off the gate type optical amplifier 51. Then, the signal light of 1530 nm output from the optical transmitter 81 is connected to the optical transmission line 132 by the optical branch 41, and is output to the optical transmission line 120 via the optical demultiplexer / demultiplexer 410.

Optical transmission lines 132-1 through which light of another wavelength flows
34 is also connected to the optical multiplexer / demultiplexer 410 through the same configuration and output to the optical transmission line 120. As described above, it is possible to pass (amplify), drop, and insert an optical signal of an arbitrary wavelength in the node.

Since the wavelength division multiplexing optical branches 151 to 154 can multiplex and demultiplex light of different wavelengths with low loss, the use of the wavelength multiplexing optical branches 151 to 154 is 5 dB or more as compared with the conventional one-to-one optical branch. A low-loss optical repeater amplifier circuit can be realized.

FIG. 3 is a block diagram showing another embodiment of the present invention. In this embodiment, each combination of the optical isolators 91 to 94 and the wavelength division multiplexing optical branches 151 to 154 in the first embodiment is
It is replaced with optical circulators 61 to 64.
Even with this method, an effect equivalent to that of the first embodiment can be obtained, and an optical repeater amplifier circuit having a loss of 5 dB or less as compared with the case of using a conventional one-to-one optical branch can be realized.

FIG. 4 is a block diagram showing another embodiment of the present invention. This embodiment is applied to a node that does not perform optical add / drop and performs only optical repeater amplification.

Referring to FIG. 4, a wavelength 1
530nm, 1540nm, 1550nm, 1560n
m are multiplexed. These lights are transmitted to an optical multiplexer / demultiplexer 41 represented by an arrayed waveguide diffraction grating.
0 and output to different optical transmission lines. In other words, each of the optical transmission lines 131 to 134 has only one wavelength of light.

1530 nm output to the optical transmission line 131
Is output to the optical amplifier 55 by the demultiplexing function of the wavelength division multiplexing optical branch 151. The signal light optically amplified by the optical amplifier 55 passes through the optical isolator 91 to the wavelength division multiplexing optical branch 15.
2 and output to the optical transmission line 132 by the multiplexing function of the wavelength division multiplexing optical branch 152. And the optical demultiplexer 410
And output to the optical transmission line 120.

Optical transmission lines 132-1 through which light of other wavelengths flows
34 is also connected to the optical multiplexer / demultiplexer 410 via the same configuration and output to the optical transmission line 120. In this embodiment, by providing a means for controlling the gain of each of the optical amplifiers 55 to 58, the optical level of each wavelength of the wavelength multiplexed light can be equalized. Further, an optical amplifier with a small noise component can be realized by the filter effect of the optical multiplexer 410.

The wavelength division multiplexing optical branches 151 to 154 are capable of demultiplexing and multiplexing light having different wavelengths with low loss.
As compared with the case where one-to-one optical branching is used, it is possible to reduce the loss by 5 dB or more. Further, since each wavelength is individually amplified, a higher gain is achieved as compared with the wavelength multiplexed optical collective optical amplification. Can be realized.

FIG. 5 is a block diagram showing another embodiment of the present invention. In FIG. 5, the optical transmission line 110 has wavelengths of 1530 nm, 1540 nm, 1550 nm, and 156 nm.
Four signal lights of 0 nm are wavelength-multiplexed. After these signal lights are collectively amplified by the optical amplifier 55, they are input to an optical multiplexer / demultiplexer 410 represented by an arrayed waveguide diffraction grating, and output to different optical transmission lines 131 to 134, respectively. In other words, each of the optical transmission lines 131 to 134 has only one wavelength of light.

1530 nm output to the optical transmission line 131
Is output to the optical attenuator 181 by the demultiplexing function of the wavelength division multiplexing optical branch 151. The signal light optically attenuated by the optical attenuator 181 is input to the wavelength division multiplexing optical branch 152 via the optical isolator 91, and is output to the optical transmission line 132 by the multiplexing function of the wavelength division multiplexing optical branch 152. The light is input to the optical multiplexer / demultiplexer 410 and output to the optical transmission line 120. The optical transmission lines 132 to 134 through which light of other wavelengths flows are connected to the optical multiplexer / demultiplexer 410 via the same configuration and output to the optical transmission line 120.

By controlling the amount of attenuation of each of the optical attenuators 181 to 184, the optical level of each wavelength of the wavelength multiplexed light can be equalized. In addition, the noise component is small due to the filter effect of the optical multiplexer / demultiplexer, and the wavelength division multiplexing optical branches 151 to 15
4 is capable of demultiplexing light of different wavelengths with low loss.
An optical gain equalizer with a low loss of 5 dB or more can be realized as compared with the case where a conventional one-to-one optical branch is used.

FIG. 6 is a block diagram showing an embodiment of an EDFA gate switch usable in the optical repeater amplifier according to the present invention. In FIG. 6, a signal light having a wavelength of 1550 nm is transmitted through an optical transmission line 121. The pumping light having a wavelength of 1480 nm output from the pumping light source 161 passes through the optical transmission line 122, is multiplexed by the wavelength division multiplexing optical branch 155 connected to the optical transmission line 121, and is combined with the EDF 141.
Is input to From the EDF 141, the optically amplified wavelength 1
Excitation light having a wavelength of 1480 nm that cannot be absorbed by the EDF 141 is output simultaneously with the signal light of 550 nm.

The signal light and the pump light are optically demultiplexed by the wavelength division multiplexing optical branch 156 provided behind the EDF 141, and the signal light and the pump light are output to the optical transmission line 121 as they are and the latter to the optical transmission line 123. By this method, the signal light and the pump light are separated,
The pump light output to the rear of the gate switch is suppressed, and damage to the optical components due to strong excitation light input to the optical components connected behind the gate switch can be prevented. That is, by using the optical repeater of this embodiment in the wavelength division multiplex optical repeater, the optical multiplexer / demultiplexer 410
Pump light that is strong with respect to the optical multiplexer / demultiplexer 410 can be prevented, and damage to the optical multiplexer / demultiplexer 410 can be prevented.

FIG. 7 is a block diagram showing another embodiment of the EDFA gate switch usable in the optical repeater amplifier according to the present invention. In FIG. 7, the optical transmission line 121
Is transmitting a signal light having a wavelength of 1550 nm. The pumping light having a wavelength of 1480 nm output from the pumping light source 163 passes through the optical transmission line 122, is multiplexed by the wavelength division multiplexing optical branch 157 connected to the optical transmission line 121, and is EDF.
141. The EDF 141 simultaneously outputs the optically amplified signal light having a wavelength of 1550 nm and pump light having a wavelength of 1480 nm that cannot be absorbed by the EDF 141 at the same time.

The signal light and the pump light are optically demultiplexed by the wavelength division multiplexing optical branch 158 provided behind the EDF 141, and the former is output to the optical transmission line 121 as it is, and the latter is output to the optical transmission line 123. The pump light output to the optical transmission line 123 is reflected by a wavelength-selective light reflecting mirror 25 represented by a fiber Bragg grating, and is again reflected by the EDF 141.
To increase the pumping efficiency of the EDF.

According to this method, the signal light and the pumping light are separated, the pumping light output to the rear of the gate switch is suppressed, and the optical component connected to the rear of the gate switch is damaged by the strong pumping light input. Can be prevented. Further, by monitoring the intensity of the leaked light having a wavelength of 1550 nm that has passed through the light reflection mirror 25 with the optical monitor 200, it is possible to perform light level control and fault monitoring.

FIG. 8 is a block diagram showing still another embodiment of the EDFA gate switch usable in the optical repeater amplifier according to the present invention. In FIG. 8, a signal light having a wavelength of 1550 nm is transmitted through an optical transmission line 121. The excitation light having a wavelength of 1480 nm output from the excitation light source 163 passes through the optical transmission line 122 and passes through the optical transmission line 121.
Multiplexed by the wavelength division multiplexing optical branch 157 connected to
This is input to the EDF 141. On the other hand, the pump light having a wavelength of 1480 nm output from the pump light source 164 is also transmitted through the optical transmission line 123.
, And are multiplexed by the wavelength division multiplexing optical branch 158 connected to the optical transmission line 121 and input to the EDF 141.
The wavelength 1 which could not be absorbed by the EDF 141 together with the optically amplified signal light having a wavelength of 1550 nm from the EDF 141.
480 nm excitation light is output simultaneously.

The signal light and the pump light are optically demultiplexed by the wavelength division multiplexing optical branch 158 provided behind the EDF 141, and the signal light and the pump light are outputted to the optical transmission line 121 as they are and the latter to the optical transmission line 123. Further, the pumping light output in front of the EDF 141 is optically branched by the wavelength division multiplexing optical branch 157 and output to the optical transmission line 122.

According to this method, the signal light and the pump light are separated, the pump light output to the rear of the gate switch is suppressed, and the optical component is damaged by the strong pump light input to the optical component connected behind the gate switch. Can be prevented. Further, by dispersing the excitation light sources, the intensity of each excitation light source can be reduced.

FIG. 9 is a diagram showing another embodiment of the present invention in which a wavelength optical add / drop multiplexer is configured using the above-mentioned EDFA gate switch. In FIG. 9, the optical transmission line 110
Are wavelength multiplexed with two signal lights having wavelengths of 1548 nm and 1554 nm. These signal lights are input to an optical splitter 210 represented by an arrayed waveguide grating and output to different optical transmission lines 131 and 132, respectively. That is, each of the optical transmission lines 131 and 132 has only one wavelength of light.

The operation of the wavelength ADM of this embodiment will be described with respect to passing, dropping, and insertion. At the time of passage, the excitation light source 161 is in an operating state, and the excitation light having a wavelength of 1480 nm output from the excitation light source 161 is
The wavelength division multiplexing light 151 multiplexes the signal light of 1548 nm output to the optical transmission line 131 and inputs the signal light to the EDF 141. In the EDF 141, the wavelength is 1548 nm.
Is amplified and output together with the pump light not absorbed by the EDF 141. The signal light and the pump light are split by the wavelength division multiplexing optical branch 152, and the signal light is output to the optical transmission line 120 via the optical multiplexer 310.

Regarding the branch, the signal light of 1548 nm output to the transmission line 131 is input to the optical receiver 71 connected to the optical branch 31 and received.

At the time of insertion, by turning off the output from the pump light source 161, the EDF 141 is put into an inactive state, and the 1548 nm signal light output from the optical demultiplexer 210 to the transmission line 131 is cut off. On the other hand, the excitation light source 1
The pumping light having a wavelength of 1480 nm output from 63 is input to the EDF 143 via the wavelength division multiplexing optical branch 155,
When the 1548 nm insertion signal light output from the optical transmitter 81 is input to the EDF 143 via the wavelength division multiplexing optical branch 155, the insertion signal light is optically amplified by the EDF 143,
The light is output to the optical transmission line 131 by the optical branch 41 together with the excitation light that cannot be absorbed by the EDF 143. Further, the signal is demultiplexed by the wavelength division multiplexing optical branch 152, the insertion signal light is supplied to the optical multiplexer 310, and the pump light is supplied to the band pass filter 171.
Output to

The optical transmission line 132 through which light of another wavelength flows is connected to the optical multiplexer / demultiplexer 410 through the same configuration and is output to the optical transmission line 120. As described above, it becomes possible to pass, drop, and insert an optical signal of an arbitrary wavelength in the node.

The wavelength 148 flowing through the transmission lines 131 and 132
The 0-nm pump light is not input to the optical multiplexer 310 because it is split by the wavelength division multiplexing optical branches 152 and 154. Therefore, the EDFs 141 to 144 can be used without damaging the optical multiplexer.
Can be increased.

The wavelength 1548n output to the optical transmission lines 135 and 136 from the wavelength division multiplexing optical branches 152 and 154, respectively.
m, 1554 nm of leaked light
The light is extracted at 1, 172, and the light intensity can be monitored by the optical monitor 200. Using the result, the optical level control of the wavelength multiplexed light and the failure monitoring of the wavelength multiplexing optical add / drop device can be performed.

FIG. 10 is a diagram showing another embodiment of the present invention in which a wavelength optical add / drop multiplexer is constructed using the above-mentioned EDFA gate switch. In FIG. 10, the optical transmission line 1
10 has wavelengths of 1530 nm, 1540 nm, 1550
and four signal lights of 1560 nm are wavelength-multiplexed. These signal lights are input to an optical multiplexer / demultiplexer 410 represented by an arrayed waveguide diffraction grating via an optical circulator 60, and output to different optical transmission paths 131 to 134, respectively. In other words, each of the optical transmission lines 131 to 134 has only one wavelength of light.

The operation (pass, drop, add) of the wavelength light ADM of this embodiment will be described below. At the time of passage, the wavelength output from the excitation light source 161 is 1480 nm.
The excitation light is input to the EDF 141 after passing through a light reflection mirror 21 which transmits the excitation light and reflects the signal light, which is represented by a fiber Bragg mirror. The signal light of 1530 nm output to the optical transmission line 131 is input to the EDF 141, and after being optically amplified, is output together with the pump light not absorbed by the EDF 141. Then, only the signal light is reflected by the wavelength-selective light reflecting mirror 21, and the EDF is again reflected.
The light is amplified at 141 and output to the optical transmission line 131 together with the excitation light not absorbed by the EDF 141. The signal light and the pump light are demultiplexed by the wavelength division multiplexing optical branch 191, and only the signal light is output to the optical demultiplexer / demultiplexer 410.

Regarding the branch, the signal light of 1548 nm output to the transmission line 131 is input to the optical receiver 71 connected to the optical branch 31 and received.

At the time of insertion, the output from the pumping light source 161 is turned off so that the EDF 141 is in an inactive state, and the signal light of 1548 nm output from the optical multiplexer / demultiplexer 410 to the transmission line 131 is cut off. On the other hand, the pumping light having a wavelength of 1480 nm output from the pumping light source 165 is input to the EDF 145 via the wavelength division multiplexing optical branch 155, and the 1548 nm insertion signal light output from the optical transmitter 81 is transmitted via the wavelength division multiplexing optical branch 155. When the input signal light is input to the EDF 145, the inserted signal light is optically amplified by the EDF 145 and output to the optical transmission line 131 by the optical branch 41 together with the pump light that cannot be absorbed by the EDF 145. Further, the signal is demultiplexed by the wavelength division multiplexing optical branch 191, the insertion signal light is output to the optical multiplexer / demultiplexer 410, and the pump light is output to the bandpass filter 171.

Optical transmission lines 132-1 through which light of other wavelengths flows
34 is also connected to the optical multiplexer / demultiplexer 410 through the same configuration, output to the optical transmission line 120, and output to the optical transmission line 121 via the optical circulator 60. As described above, it becomes possible to pass, drop, and insert an optical signal of an arbitrary wavelength in the node.

The wavelength 148 flowing through the transmission lines 131 to 134
The 0-nm pump light is not input to the optical demultiplexer / demultiplexer 410 because it is split by the wavelength division multiplexing optical branches 191 to 194. Therefore, without damaging the optical multiplexer / demultiplexer 410, the ED
The gain in F141 to 148 can be increased.

Further, the leaked light of each wavelength output from the wavelength division multiplexing optical branches 191 to 194 to the optical transmission lines 135 to 138 can be taken out by the band pass filters 171 to 174, and the light intensity can be monitored by the optical monitor 200. Using this, it is possible to control the optical level of the wavelength division multiplexed light and to monitor the failure of the wavelength division multiplexing optical add / drop device.

FIG. 11 is a diagram showing another embodiment of the present invention in which a wavelength optical add / drop device is constituted by using the above-mentioned EDFA gate switch. In FIG. 11, the optical transmission line 1
10 has wavelengths of 1530 nm, 1540 nm, 1550
and four signal lights of 1560 nm are wavelength-multiplexed. These signal lights are input to an optical multiplexer / demultiplexer 410 represented by an arrayed waveguide diffraction grating, and output to different optical transmission paths 131 to 134, respectively. In other words, each of the optical transmission lines 131 to 134 has only one wavelength of light.

The operation (pass, drop, add) of the wavelength light ADM in this embodiment will be described below. At the time of passage, the wavelength 148 output from the excitation light source 161
The excitation light of 0 nm is multiplexed by the optical branch 195,
It has been input to the DF 141. The signal light of 1530 nm output to the optical transmission path 131 is input to the EDF 141 after passing through the wavelength division multiplexing optical branch 151, and is optically amplified.
It is output together with the excitation light not absorbed by the EDF.
The output signal light and pump light are demultiplexed by the wavelength division multiplexing optical branch 191, and the signal light is input to the wavelength division multiplexing optical branch 152 via the optical isolator 91 and is transmitted via the optical transmission line 132 to the optical demultiplexer 410. Is output to

Regarding the branch, the signal light of 1530 nm output to the transmission line 131 is input to the optical receiver 71 connected to the optical branch 31 and received.

At the time of insertion, the output from the pump light source 161 is turned off, so that the EDF 141 is in an inactive state, and the signal light of 1548 nm output from the optical multiplexer / demultiplexer 410 to the transmission line 131 is cut off. On the other hand, the pumping light having a wavelength of 1480 nm output from the pumping light source 165 is input to the EDF 145 via the wavelength division multiplexing optical branch 155, and the 1548 nm insertion signal light output from the optical transmitter 81 is transmitted via the wavelength division multiplexing optical branch 155. When input to the EDF 145, the inserted signal light is optically amplified by the EDF 145, and is output to the optical transmission line by the optical branch 41 together with the pump light that cannot be absorbed by the EDF 145. Further, the added signal light is split by the wavelength division multiplexing optical branch 191, is input to the wavelength division multiplexing optical branch 152 via the optical isolator 91, and is output to the optical demultiplexer / demultiplexer 410 via the optical transmission line 132. The excitation light is output to the band pass filter 171.

Optical transmission lines 132-1 through which light of other wavelengths flows
34 is also connected to the optical multiplexer / demultiplexer 410 via the same configuration and output to the optical transmission line 120. From the above,
Optical signals of an arbitrary wavelength can be passed, dropped, and inserted in the node.

In this embodiment, the optical transmission line 13
Wavelength division multiplexing optical branches 151 to 15 for connecting 1 to 134
4 is capable of demultiplexing light of different wavelengths with low loss.
It is possible to realize an optical add / drop circuit having a loss of 5 dB or more as compared with the case where the conventional one-to-one optical branch is used.

The pump light having a wavelength of 1480 nm flowing through the transmission lines 131 to 134 is supplied to the wavelength division multiplexing optical branches 191 to 19.
4 is not input to the optical multiplexer / demultiplexer 410. Therefore, the EDF 1 can be used without damaging the optical multiplexer / demultiplexer.
The gain at 41 to 148 can be increased.

Further, the leaked light of each wavelength output from the wavelength division multiplexing optical branches 191 to 194 to the optical transmission lines 135 to 138 can be taken out by the band pass filters 171 to 174, and the light intensity can be monitored by the optical monitor 200. Using this, it is possible to control the optical level of the wavelength division multiplexed light and to monitor the failure of the wavelength division multiplexing optical add / drop device.

FIG. 12 is a diagram showing another embodiment of the optical repeater / amplifier of the present invention. In FIG. 12, two signal lights having wavelengths of 1548 nm and 1554 nm are wavelength-multiplexed in the optical transmission line 110. These signal lights are input to an optical splitter 210 represented by an arrayed waveguide diffraction grating, and output to different optical transmission paths 131 and 132, respectively. That is, each of the optical transmission lines 131 and 132 has only one wavelength of light.

The 1548 nm signal light output from the optical demultiplexer 210 to the optical transmission line 131 and the 1480 nm wavelength excitation light output from the excitation light source 161 to the optical transmission line 133 are
The signals are multiplexed by the wavelength division multiplexing optical branch 151,
Is input to Therefore, the signal light having a wavelength of 1548 nm is
The light is amplified by the EDF 141 and output together with the excitation light not absorbed by the EDF 141. The signal light and the pump light are split by the wavelength division multiplexing optical branch 152, and the signal light is output to the optical transmission line 120 via the optical multiplexer 310. The optical transmission line 132 through which light of other wavelengths flows is connected to the optical multiplexer 310 through the same configuration, and the optical transmission line 1
20.

In this embodiment, each excitation light source 16
By providing the means for controlling the pump light intensity of the light pumps 1 and 162, it becomes possible to control the gain of the optical amplifier connected to each transmission line, so that the optical level of each wavelength of the wavelength multiplexed light can be equalized. In addition, an optical amplifier having a small noise component can be realized by the filter effect of the optical demultiplexer and the optical multiplexer.

The wavelength 148 flowing through the transmission lines 131 and 132
Since the 0-nm pump light is split by the wavelength division multiplexing optical branches 152 and 154, it is not input to the optical multiplexer 310.
Therefore, the EDFs 141 and 14 can be used without damaging the optical multiplexer.
2 can be increased.

The wavelengths 1548n output from the wavelength division multiplexing optical branches 152 and 154 to the optical transmission lines 135 and 136, respectively.
m, 1554 nm of leaked light
The light is extracted at 1, 172, and the light intensity can be monitored by the optical monitor 200. Using this result, the optical level control of the wavelength multiplexed light and the failure monitoring of the optical amplifier can be performed.

FIG. 13 is a diagram showing another embodiment of the optical repeater / amplifier of the present invention. In FIG. 13, the optical transmission line 110 has wavelengths of 1530 nm, 1540 nm, and 155 nm.
Four signal lights of 0 nm and 1560 nm are wavelength-multiplexed. These signal lights are input to an optical multiplexer / demultiplexer 410 represented by an arrayed waveguide diffraction grating via an optical circulator 60, and output to different optical transmission paths 131 to 134, respectively. In other words, each of the optical transmission lines 131 to 134 has only one wavelength of light.

The 1530 nm signal light split by the optical multiplexer / demultiplexer 410 and output to the optical transmission line 131 is transmitted to the EDF 1
41 is input. On the other hand, the excitation light having a wavelength of 1480 nm output from the excitation light source 161 passes through the light reflection mirror 21 typified by a fiber Bragg mirror and passes through the EDF 141
, The signal light with a wavelength of 1530 nm is E
After being optically amplified by the DF 141, only the signal light is reflected by the light reflection mirror 21, amplified again by the EDF 141, and output to the optical transmission line 131 together with the excitation light not absorbed by the EDF 141. The signal light and the pump light are
The signal is demultiplexed by the wavelength division multiplexing optical branch 191, and only the signal light is output to the optical demultiplexer / demultiplexer 410.

Optical transmission lines 132-1 through which light of another wavelength flows
34 is also connected to the optical multiplexer / demultiplexer 410 through the same configuration, output to the optical transmission line 120, and output to the optical transmission line 121 via the optical circulator 60.

Also in this embodiment, each excitation light source 1
By controlling the pumping light intensity of 61 to 164, the gain of each optical amplifier can be controlled, so that the optical level of each wavelength of the wavelength multiplexed light can be equalized. Further, an optical amplifier having a small noise component can be realized by the filter effect of the optical multiplexer / demultiplexer. Furthermore, since the optical amplification is performed individually for each wavelength, a higher optical output can be obtained as compared with the wavelength multiplexed optical collective optical amplification.

The pump light having a wavelength of 1480 nm flowing through the transmission lines 131 to 134 is supplied to the wavelength division multiplexing optical branches 191 to 19.
4 is not input to the optical multiplexer / demultiplexer 410. Therefore, the EDF 1 can be used without damaging the optical multiplexer / demultiplexer.
The gain in 41 to 144 can be increased.

Also, the leak light of each wavelength output from the wavelength division multiplexing optical branches 191 to 194 to the optical transmission lines 135 to 138 can be taken out by the band pass filters 171 to 174, and the light intensity can be monitored by the optical monitor 200. By using this, it is possible to perform optical level control of wavelength multiplexed light and fault monitoring of an optical amplifier.

FIG. 14 is a diagram showing another embodiment of the wavelength division multiplexing optical repeater / amplifier of the present invention. In FIG.
The optical transmission line 110 has a wavelength of 1530 nm and 1540 n.
Four signal lights of m, 1550 nm, and 1560 nm are wavelength-multiplexed. These signal lights are input to an optical multiplexer / demultiplexer 410 represented by an arrayed waveguide diffraction grating, and output to different optical transmission paths. That is, the optical transmission line 1
There is only one wavelength of light in each of 31-134.

1530 nm output to the optical transmission line 131
After passing through the wavelength division multiplexing optical branch 151, the signal light of wavelength 1 output from the pump light source 161 by the optical branch 195.
The light is multiplexed with the 480 nm excitation light and input to the EDF 141. The signal light having a wavelength of 1530 nm is optically amplified by the EDF 141 and output together with the pump light not absorbed by the EDF 141. The signal light and the pump light are split by the wavelength division multiplexing optical branch 191, and the signal light is input to the wavelength division multiplexing optical branch 152 via the optical isolator 91 and output to the optical demultiplexer / demultiplexer 410. Optical transmission line 1 through which light of another wavelength flows
32 to 134 are also connected to the optical multiplexer / demultiplexer 410 via the same configuration and output to the optical transmission line 120.

Also in this embodiment, each excitation light source 1
By providing the means for controlling the pumping light intensity of 61 to 164, the gain of each optical amplifier can be controlled, so that the optical level of each wavelength of the wavelength multiplexed light can be equalized.
Further, an optical amplifier having a small noise component can be realized by the filter effect of the optical multiplexer / demultiplexer.

The wavelength multiplexing optical branches 151 to 154 connecting the optical transmission lines 131 to 134 can separate and multiplex light of different wavelengths with low loss, so that a conventional one-to-one optical branch is used. An optical repeater with a loss of 5 dB or more as compared with the case can be realized. Further, the excitation light having a wavelength of 1480 nm flowing through the transmission lines 131 to 134 is
Since they are demultiplexed by 1 to 194, they are not input to the optical multiplexer / demultiplexer 410. Therefore, the gain in the EDFs 141 to 148 can be increased without damaging the optical multiplexer / demultiplexer.

Further, the leaked light of each wavelength output from the wavelength division multiplexing optical branches 191 to 194 to the optical transmission lines 135 to 138 can be extracted by the band pass filters 171 to 174 and the light intensity can be monitored by the optical monitor 200. By utilizing this, it is possible to perform optical level control of wavelength multiplexed light and fault monitoring of the wavelength multiplexed optical amplifier.

In the embodiment of the present invention, the number of multiplexed wavelengths in the optical transmission line is described as 2 or 4, but the present invention is not limited to this.
Any number of wavelengths such as 8, 16, 32, and 64 can be set. Further, the wavelength of the input light is not limited to the 1550 nm band, but can be freely set to the 1300 nm band. Also, the signal speed is not particularly limited.
Bit rate-free settings of 2.5 Gbps, 5 Gbps, and 10 Gbps are possible.

The optical demultiplexer, the optical multiplexer, and the optical multiplexer / demultiplexer have been described by taking the arrayed waveguide diffraction grating as an example. However, a wavelength router having a grating structure having the same function, a wavelength router, The present invention can be implemented by changing a MUX coupler or the like or a combination of a light branching and an interference film filter having the same function. further,
The optical demultiplexer, optical multiplexer, and optical multiplexer / demultiplexer represented by an arrayed waveguide diffraction grating have different insertion loss depending on each wavelength. Therefore, an optical attenuator is appropriately inserted into each waveguide to achieve an optical level. Can be performed.

Similarly, by controlling the gain of each EDFA gate and optical amplifier, or
By controlling the reflectivity of the light reflecting mirror in the third embodiment, it is possible to equalize the light level for each wavelength.

Further, the installation position of the optical branch for optical branching and insertion shown in each embodiment can be freely changed within a range that does not hinder the functions of branching, inserting and passing.

The structure of the EDFA gate is particularly
The fiber is not limited to F (erbium-doped fiber), but may be replaced by a material having a configuration in which aluminum, tellurium, or the like is added to the fiber as an impurity, and the fiber is excited by a pump light source to perform optical amplification. Further, the wavelength of the excitation light is 148.
It is not limited to 0 nm, and 980 nm or the like can be used instead. Further, the length of the impurity-doped optical fiber can also be appropriately set to any value depending on the doping amount, the excitation light intensity, the required extinction ratio as a switch, the insertion loss, and the like.
When integrating, it is possible to minimize the length in consideration of the above setting. Further, the pumping method can be freely set according to the application, such as forward pumping, backward pumping, forward / backward pumping, and polarization multiplexing.

The combination of the optical branch and the optical isolator can be replaced with an optical circulator.

Further, in the embodiment of the loop-back configuration, in the wavelength division multiplexing optical branch for connecting the optical transmission lines, it is preferable to demultiplex and multiplex signal lights having wavelengths as far apart as possible to reduce insertion loss and crosstalk. Is advantageous in terms of

[0085]

As described above, according to the present invention,
By using the wavelength division multiplexing optical branch, the insertion loss in the node can be reduced. Also, by arranging a wavelength division multiplexing optical branch behind the EDFA gate switch,
Excitation light that could not be absorbed by the DF can be split,
The output of the excitation light to the rear of the gate switch can be suppressed to prevent damage to the optical components. Therefore, it is possible to reduce the size of the device and increase the transmission distance between nodes, thereby reducing the communication cost.

[0086]

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration of a wavelength division multiplexing optical branch used in an embodiment of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration of an optical repeater amplifier according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of an optical repeater amplifier according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating a configuration of an optical repeater amplifier according to an embodiment of the present invention.

FIG. 9 is a diagram showing another embodiment of the present invention.

FIG. 10 is a diagram showing another embodiment of the present invention.

FIG. 11 is a diagram showing another embodiment of the present invention.

FIG. 12 is a diagram showing another embodiment of the present invention.

FIG. 13 is a diagram showing another embodiment of the present invention.

FIG. 14 is a diagram showing another embodiment of the present invention.

FIG. 15 is a diagram showing a conventional example.

[Explanation of symbols]

 110, 120, 121, 131-138 Optical transmission line 11-14, 31-34, 41-44 Optical branching 21-25 Light reflecting mirror 51-54 Gate type optical amplifier 55-58 Optical amplifier 60-64 Optical circulator 71- 74 optical receiver 81-84 optical transmitter 91-94 optical isolator 141-148 EDF 151-158, 191-194 wavelength division multiplexing optical branching 161-168 excitation light source 171-174 bandpass filter 181-184 optical attenuator 200 optical monitor 210 optical demultiplexer 310 optical multiplexer 410 optical demultiplexer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/02

Claims (20)

[Claims] 1. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and multiplexing the demultiplexed light for wavelength multiplexing and outputting the multiplexed light to an optical transmission line. On the one hand, light connected to the optical multiplexer / demultiplexer and inputting / outputting light separated for each wavelength is input / output, and on the other hand, light separated for each wavelength output from the optical multiplexer / demultiplexer is optically branched. First
And an optical receiver connected to each one optical output of the first optical branch; and an optical transmitter corresponding to each optical receiver and having one optical output constituting the wavelength multiplexed light. An optical gate switch corresponding to each of the plurality of demultiplexed lights and controlling passage and blocking of light; and an optical isolator corresponding to each of the plurality of demultiplexed lights and passing the corresponding light of the optical gate switch. Corresponding to each of the plurality of demultiplexed lights, while the first
A second optical branch that is connected to the optical input / output of each of the optical branches of the optical branch, and optically branches each of the lights separated for each input / output wavelength, and that receives the light from the optical transmitter; The second optical branch is connected to the optical input / output, and on the other hand, the light of the first wavelength input from the second optical branch is output to the optical gate switch, and on the other hand, the first light is output from the optical isolator to the first A wavelength-multiplexed optical branch that inputs an optical output of a second wavelength different from the wavelength and outputs the optical output to the second optical branch, wherein each of the lights separated for each wavelength is output from the optical multiplexer / demultiplexer. After passing through the first and second optical branches, the wavelength multiplexing optical branch, the optical gate switch, and the optical isolator, the wavelength multiplexing optical branches corresponding to the separated adjacent wavelengths; Returning to the optical multiplexer / demultiplexer via the second optical branch Said optical demultiplexer multiplexer WDM optical repeater having a wavelength ADM function, characterized in that the output wavelength-multiplexed by. 2. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and wavelength-multiplexing the demultiplexed light for output to the optical transmission line. One side is connected to the optical multiplexer / demultiplexer to input / output the light separated for each wavelength, and the other side optically splits the light separated for each wavelength output from the optical multiplexer / demultiplexer. A first optical branch; an optical receiver connected to each one optical output of the first optical branch; light having one optical output corresponding to each of the optical receivers and constituting the wavelength multiplexed light A transmitter, an optical gate switch corresponding to each of the plurality of demultiplexed lights and controlling passage and blocking of the light, and an optical gate switch corresponding to each of the plurality of demultiplexed lights, while the first
A second optical branch that is connected to the optical input / output of each of the optical splitters, splits each of the light separated for each input / output wavelength, and inputs light from the optical transmitter; Connected to the optical input / output of the optical branch, and outputs the light of the first wavelength input from the second optical branch to the optical gate switch, and on the other hand, an optical gate different from the optical gate switch An optical circulator having a wavelength division multiplexing optical branching function for inputting an optical output of a second wavelength different from the first wavelength from a switch and outputting the optical output to the second optical branch; Each of the separated lights passes from the optical multiplexer / demultiplexer through the first and second optical branches, the optical circulator, and the optical gate switch, and then, the optical circulator for the separated adjacent wavelengths, and First and Through the second optical branch back to the optical branching coupler, the optical demultiplexer multiplexer WDM optical repeater having a wavelength ADM function, characterized in that the output wavelength-multiplexed by. 3. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and multiplexing the demultiplexed light for wavelength output to an optical transmission line. An optical amplifier that amplifies light corresponding to each of the plurality of demultiplexed lights; and an optical isolator that passes corresponding light of the optical amplifier corresponding to each of the plurality of demultiplexed lights. The light of the first wavelength demultiplexed by the first optical multiplexer / demultiplexer is output to the optical amplifier, while the light of the second wavelength different from the first wavelength is input from the optical isolator. And a wavelength division multiplexing optical branch for outputting to the first multiplexer / demultiplexer, wherein each of the lights separated for each wavelength is, from the optical multiplexer / demultiplexer, the wavelength division multiplexing optical branch, the optical amplifier, And after passing through the optical isolator, to the separated adjacent wavelength Returning to the optical demultiplexer unit through the long multiplexed light branching the wavelength division multiplexing optical repeater and wherein the output in wavelength-multiplexed by the optical branching coupler. 4. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and wavelength-multiplexing the demultiplexed light for output to the optical transmission line. An optical attenuator corresponding to each of the plurality of demultiplexed lights and attenuating the light, and an optical isolator corresponding to each of the plurality of demultiplexed lights and passing the corresponding light of the optical attenuator. The light of the first wavelength demultiplexed by the optical demultiplexer is output to the optical attenuator, and the light of the second wavelength different from the first wavelength is input from the optical isolator. A wavelength division multiplexing optical branch that outputs the light to the wavelength division multiplexer. The light separated for each wavelength is, from the optical wavelength division multiplexer, the wavelength division multiplexing optical branch, the optical attenuator, and the light. The wavelength division multiplexing optical branching for adjacent separated wavelengths after passing through an isolator Through the return to the optical branching coupler, wavelength division multiplexing optical repeater having an optical gain equivalent functions, characterized in that the output wavelength-multiplexed by the optical branching coupler. 5. An optical transmission line, an impurity-doped optical fiber connected to the optical transmission line, an excitation light source that inputs excitation light to the impurity-doped optical fiber and optically excites the impurity-doped optical fiber; A first wavelength division multiplexing branch for multiplexing an excitation light source and a signal light input to the optical transmission line and outputting the multiplexed light to the impurity-doped optical fiber; A second wavelength division multiplexing branch for separating the pump light not absorbed in the additional optical fiber and outputting an optically amplified signal light. 6. An optical transmission line, an impurity-doped optical fiber connected to the optical transmission line, an excitation light source that inputs excitation light to the impurity-doped optical fiber and optically excites the impurity-doped optical fiber; A first wavelength division multiplexing branch that combines the pump light source and the signal light input to the optical transmission line and outputs the combined light to the impurity-doped optical fiber, and from the signal light optically amplified by the impurity-doped optical fiber,
A second step of separating the pump light not absorbed in the impurity-doped optical fiber and outputting an optically amplified signal light;
And a light reflection mirror that receives the pump light separated by the second wavelength multiplex branch and reflects only the pump light wavelength, and a light monitor that monitors light transmitted through the reflection mirror. And the reflected excitation light is reflected by the light reflecting mirror and is again input to the impurity optical fiber via the second wavelength division multiplexing branch, and the light intensity of the leakage signal light transmitted through the light reflecting mirror is provided. An optical amplifier for optically monitoring the S / N ratio and the like. 7. An optical transmission line, an impurity-doped optical fiber connected to the optical transmission line, and a first optical pumping device that inputs pump light from an input side of the impurity-doped optical fiber and optically excites the impurity-doped optical fiber. A first wavelength division multiplexing optical branch that combines the pumping light from the first pumping light source with the signal light input to the optical transmission line and outputs the combined light to the impurity-doped optical fiber; A second excitation light source that inputs light from the output side of the impurity-doped optical fiber and optically excites the impurity-doped optical fiber; and a pump light from the second excitation light source is output from the output side of the impurity-doped optical fiber. A second wavelength-division multiplexing optical branch for inputting, wherein the signal light input to the optical transmission line is optically amplified by the impurity-doped optical fiber optically pumped by pumping light output from the first and second pumping light sources. I And an optical amplifier for separating the optically amplified signal light and the pump light output from the impurity-doped fiber by the second wavelength division multiplexing optical branch and outputting the signal light. And a means for inputting or blocking the pumping light. The pumping light is output when the pumping light is input, and the input signal light is converted into an impurity when the pumping light from the pumping light source is cut off. 8. The optical amplifier according to claim 5, wherein an optical gate switch function is provided by blocking the output by absorbing light in the doped optical fiber. 9. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from one optical transmission line for each of a plurality of wavelengths; a plurality of optical transmission lines connected to the optical demultiplexer; A first optical branch connected to each of the plurality of optical transmission lines; an optical receiver connected to one output of the first optical branch; and an optical receiver connected to the other output of the first optical branch A first doped optical fiber, at least one first pumped light source for optically pumping the first doped optical fiber, and a first pumped light source and the first doped optical fiber. A first wavelength division multiplexing optical branch to be connected, an optical transmitter corresponding to each of the optical receivers, and having one optical output constituting the wavelength division multiplexed light, respectively connected to the output of each of the optical transmitters A second doped optical fiber; and the second doped optical fiber A second pump light source for optically pumping, a second wavelength multiplexing optical branch connecting the second pump light source and the second impurity-doped optical fiber, A second optical branch for connecting each output to the plurality of transmission paths, a signal light and a pump light output from the first and second impurity-doped optical fibers, and a signal from one terminal. A third wavelength division multiplexing branch for outputting pump light from the other terminal; and a terminal connected to one terminal of the third wavelength division multiplexing optical branch, and the wavelength division multiplexing of the signal light of each wavelength to the other optical transmission line. And an optical multiplexer for outputting light.
WDM optical repeater with functions. 10. A band-pass filter connected to the other terminal of the third wavelength-division multiplexing optical branch and passing only the signal light wavelength; and a light intensity of the leaked signal light, S / S connected to the band-pass filter. 10. The wavelength division multiplexing optical repeater according to claim 9, further comprising optical monitoring means for monitoring an N ratio and the like. 11. An optical circulator for inputting wavelength-division multiplexed light from one optical transmission line and outputting wavelength-division multiplexed light to the other optical transmission line. An optical multiplexer / demultiplexer that outputs a plurality of wavelength lights demultiplexed for each wavelength while inputting the plurality of demultiplexed wavelength lights and wavelength multiplexing and outputs the input / output of the optical circulator; A first optical branch connected to each of the plurality of optical transmission lines, an optical receiver connected to each one optical output of the first optical branch, and a plurality of optical transmission lines, respectively. A first impurity-doped fiber, one of which is connected to the other, a light-reflecting mirror connected to the other of the first impurity-doped fibers and reflecting signal light and transmitting excitation light, and via the light-reflecting mirror. The first impurity A first pumping light source that is connected to the doped optical fiber and optically pumps the first impurity-doped optical fiber; and an optical transmitter that has one optical output corresponding to each of the optical receivers and constituting the wavelength multiplexed light. A second doped optical fiber connected to an output of the optical transmitter; a second pump light source for optically pumping the second doped optical fiber; a second pump light source; A first wavelength-division multiplexing optical branch that connects to the impurity-doped optical fiber; and a second optical branch that connects each output of the second impurity-doped optical fiber to the plurality of transmission paths. Each of the signal lights connected to the multiplexer / demultiplexer and separated for each wavelength is inputted and outputted to the first doped fiber side, and on the other hand, outputted from the first and second doped optical fibers. Excitation A second wavelength division multiplexing optical branching device for demultiplexing light and signal light and outputting the signal light to the optical multiplexer / demultiplexer; . 12. A band-pass filter connected to the pumping light output of the second wavelength division multiplexing optical branch and passing only the signal light wavelength, and connected to the band-pass filter, the light intensity and the S / N ratio of the leaked signal light. 12. The wavelength division multiplexing optical repeater according to claim 11, further comprising an optical monitor for monitoring the operation. 13. An optical multiplexer / demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and wavelength-multiplexing the demultiplexed light for output to the optical transmission line. On the one hand, light connected to the optical multiplexer / demultiplexer and inputting / outputting the light separated for each wavelength is input / output, and, on the other hand, the light separated for each wavelength output from the optical multiplexer / demultiplexer is optically branched. First
An optical receiver connected to each of the optical outputs of the first optical branch; and lights respectively corresponding to the optical receivers and having an optical output constituting the wavelength multiplexed light. A transmitter; a first impurity-doped optical fiber corresponding to each of the plurality of demultiplexed lights; a first pump light source for optically pumping the first impurity-doped optical fiber; A first wavelength division multiplexing optical branch for connecting a light source and the first impurity-doped optical fiber, and a light corresponding to each of the plurality of demultiplexed lights and passing the corresponding light of the first impurity-doped optical fiber An isolator, a second impurity-doped optical fiber connected to the output of the optical transmitter, a second pump light source for optically pumping the second impurity-doped optical fiber, Second doped light A second wavelength-division multiplexing optical branch for connecting the fiber, a second optical branch for connecting the output of the second impurity-doped optical fiber and the plurality of transmission paths, and the first and second impurity-doping. A third wavelength division multiplexing optical branch that receives an output of an optical fiber, separates signal light and pump light included in the output of each impurity-doped optical fiber, and outputs signal light to the optical isolator; Connected to an optical input / output of an optical branch, and outputs light of a first wavelength input from the first optical branch to the first wavelength multiplexing branch, and, on the other hand, from the optical isolator to the first And a fourth wavelength-division multiplexing optical branch for inputting an optical output of a second wavelength different from the wavelength of the second wavelength and outputting the optical output to the multiplexer / demultiplexer via the first optical branch. Each of the light beams from the optical multiplexer / demultiplexer, Branch, the fourth wavelength division multiplexing branch, the first wavelength division multiplexing branch, the first impurity-doped optical fiber, and the fourth wavelength division multiplexing branch for the separated adjacent wavelength after passing through the optical isolator. Returning to the optical multiplexer / demultiplexer via the second optical branch, and multiplexing and outputting the wavelength multiplexed light from the optical multiplexer / demultiplexer. apparatus. 14. A band-pass filter connected to the pumping light output separated by the third wavelength division multiplexing optical branch and passing only the signal light; and a light intensity of the leaked signal light connected to the band-pass filter. 14. The wavelength division multiplexing optical repeater according to claim 13, further comprising optical monitoring means for monitoring an S / N ratio and the like. 15. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from one optical transmission line for each of a plurality of wavelengths, and a signal of each demultiplexed wavelength connected to the optical demultiplexer. A plurality of optical transmission lines for transmitting light; an impurity-doped optical fiber connected to each of the plurality of optical transmission lines; an excitation light source for optically exciting the impurity-doped optical fiber; and the excitation light source and the impurity addition A first wavelength division multiplexing optical branch for connecting an optical fiber, a second wavelength division multiplexing optical branch for separating pump light and signal light output from the impurity-doped optical fiber, and a second wavelength division multiplexing optical branch. An optical multiplexer connected to the signal light output, for wavelength multiplexing the signal light of each wavelength to the other optical transmission line, and outputting the multiplexed light. 16. A band-pass filter connected to the pumping light output separated by the second wavelength division multiplexing optical branch and passing only the signal light, and a light intensity of the leaked signal light connected to the band-pass filter. 16. The wavelength division multiplexing optical repeater / amplifier according to claim 15, further comprising optical monitoring means for monitoring an S / N ratio and the like. 17. An optical circulator for inputting wavelength-division multiplexed light from one optical transmission line and outputting wavelength-division multiplexed light to the other optical transmission line. An optical multiplexer / demultiplexer that outputs a plurality of wavelength lights demultiplexed for each wavelength while inputting the plurality of demultiplexed wavelength lights and wavelength multiplexing and outputs the input / output of the optical circulator; An impurity-doped optical fiber, one of which is connected to each of the plurality of optical transmission lines, and each of which is connected to the other of the impurity-doped optical fibers,
A light reflection mirror that reflects the signal light and transmits the excitation light; and an excitation light source that is connected to the impurity-doped optical fiber via the light reflection mirror and optically excites the impurity-doped optical fiber. Each of the signal lights connected to the multiplexer and separated for each wavelength is input and output to the impurity-doped optical fiber side, and on the other hand, the pump light and the signal light output from the impurity-doped optical fiber are separated. And a wavelength division multiplexing optical branching device for outputting signal light to the optical multiplexer / demultiplexer. 18. A band-pass filter connected to the pumping light output separated by the wavelength division multiplexing optical branch and passing only the signal light; and a light intensity, S / N of the leaked signal light connected to the band-pass filter. 18. The wavelength division multiplexing optical repeater / amplifier according to claim 17, further comprising optical monitoring means for monitoring a ratio or the like. 19. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and multiplexing the demultiplexed light for wavelength output to an optical transmission line. An impurity-doped fiber connected to each of the plurality of split light beams, a pump light source for optically pumping the impurity-doped optical fiber, and a second connecting the pump light source and the impurity-doped optical fiber. A wavelength division multiplexing optical branch, an optical isolator corresponding to each of the plurality of demultiplexed lights and passing corresponding light of the impurity-doped optical fiber, and an output of the impurity-doped optical fiber, A second wavelength division multiplexing optical branch that separates the signal light and the pump light included in the fiber output and outputs the signal light to the optical isolator, and is connected to the branching output of the optical multiplexer / demultiplexer; From the duplexer While outputting the input light of the first wavelength to the first wavelength division multiplexing branch, on the other hand, inputting the light output of the second wavelength different from the first wavelength from the optical isolator, and A third wavelength division multiplexing optical branch for outputting to the optical multiplexer, wherein each of the lights separated for each wavelength is supplied from the optical multiplexer / demultiplexer to the third wavelength division multiplexing branch and the first wavelength division multiplexing branch. After passing through the impurity-doped optical fiber and the optical isolator,
Returning to the optical multiplexer / demultiplexer through the wavelength division multiplexing branch, and outputting the wavelength multiplexed light from the optical multiplexer / demultiplexer. 20. A bandpass filter connected to the pumping light output separated by the second wavelength division multiplexing optical branch and passing only the signal light; and a light intensity of the leaked signal light connected to the bandpass filter, 20. The wavelength division multiplexing optical repeater / amplifier according to claim 19, further comprising optical monitoring means for monitoring an S / N ratio and the like.