JPH07283788A - Optical communication system - Google Patents

Abstract

PURPOSE:To monitor the abnormality of plural optical lines with a simple system at the same time by connecting the light signal input side of plural optical lines and the light signal output side by the optical line in a series of loop through a wavelength synthesizer by a connection unit. CONSTITUTION:The optical signal input sides 21, 22... of more than two optical lines 11, 12,... and the optical signal output sides 31, 32,... are connected in the form of a series of loop by the use of a connection unit 5 through wavelength synthesizer 41, 42,.... A port 6 inputting and outputting the monitoring light to a wavelength synthesizing and branching device 41 of the optical signal input side 21 of the optical line 11 on the leading side among more than two optical lines 11, 12,... is provided. A port 7 outputting the monitored light inputted from the port 6 to the wavelength synthesizing and branching device 4n on the optical signal output side 3n of the optical line 1n on the termination side is provided. The monitored light inputted to one port (for example, 6) rom OTDR is sent in succession to the optical lines 11, 12,.... The reflected light of the monitored light is measured by the use of the OTDR and the abnormality of many optical lines can be monitored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication system CA, for example.
The present invention relates to an optical communication system used in a TV system or the like, so that a large number of optical lines constituting the optical communication system can be easily maintained and inspected.

[0002]

2. Description of the Related Art There has been a conventional method for monitoring the abnormality of a large number of optical lines (optical fibers) constituting an optical communication system. It sends light from the OTDR to each of a number of optical lines, and emits backscattered light reflected and scattered from each optical line.
It was a method of measuring by TDR. However, this requires a light source and an OTDR for each optical line, which complicates the configuration of the optical communication system and increases the cost.

Recently, in an optical communication system such as a CATV system, when an optical signal is sent from one station to a large number of optical lines, the optical signal is not individually transmitted to a large number of optical lines, but rather as shown in FIG. As described above, an optical communication system in which an optical signal from the station A is branched by the optical branching / coupling device B and distributed to a large number of optical lines C has been put into practical use. In this optical communication system, one OTDR provided on the station A side can measure a reflected wave to detect an abnormality in the optical line.

However, in the optical communication system of FIG. 7, when the return light is measured by one OTDR provided on the side of the station A, the return lights from a large number of optical lines C are combined by the optical branching / coupling device B to be OT.
Since it returns to DR, there is a problem that it is not possible to determine which return light is from which optical line C, and it is not possible to specify the optical line C having a failure.

As a method for solving the above problem, the applicant of the present invention first inserts a filter F into each optical waveguide E on the waveguide substrate D of the optical branching / coupling device B as shown in FIG. A method for separating the measurement wavelengths of each optical line C by utilizing the angle dependence of the wavelength and measuring each optical line C at a different wavelength has been developed and filed (Japanese Patent Application No. 4-65042).

[0006]

However, in the monitoring method of FIG. 6, since the measurement is performed at multiple wavelengths, a light source is required for each wavelength, the number of light sources increases, and the measuring device becomes complicated and expensive. Not only that, but there is a problem that the measurement takes time because it is necessary to measure each optical communication line C individually.

An object of the present invention is to provide an optical communication system capable of simultaneously monitoring abnormalities in a large number of optical lines with a light source with a simple system.

[0008]

The optical communication system according to claim 1 of the present invention is, as shown in FIG. 1, an optical signal of two or more optical lines 1 ₁ , 1 ₂ ... Which can transmit an optical signal. Input side 2
_{1, 2} 2, ... and an optical signal output 3 _1, 3 _2, ..., optical line ₁ 1, 1 ₂ ... wavelength so becomes a series of loop demultiplexer 4 _1, 4 ₂ is connected by a connector 5 and the wavelength multiplexer / demultiplexer 4 on the optical signal input side 2 ₁ of the optical line 1 ₁ on the start side of the two or more optical lines 1 ₁ , 1 ₂ ... ₁ is equipped with a port 6 capable of inputting / outputting monitoring light, and an optical line 1 on the terminal side
in _{which n} of the optical signal output-side 3 _n monitoring light input from the port 6 to the wavelength demultiplexer 4 _n the is provided with a port 7 to be output.

An optical communication system according to claim 2 of the present invention, as shown in FIGS. 3 and 4, has two or more optical lines 1 according to claim 1.
₁ , 1 ₂ ... Are divided into two or more groups 8 and two or more optical lines 1 ₁ , 1 ₂ ... Of each group 8 are provided with optical signal input sides 2 ₁ , 2 ₂ ... and optical signal outputs. Side 3 ₁ , 3 _2, ...
The optical lines 1 ₁ , 1 _2, ... Are connected by a connector 5 via 4 ₁ , 4 _2, ... so as to form a series of loops.

As shown in FIG. 3, the optical communication system according to claim 3 of the present invention includes a wavelength multiplexer / demultiplexer 4 _n on the optical signal input side of the optical line 1 _n at the end of each group 8 of claim 2. Output terminal 9
Is the end of total reflection.

As shown in FIG. 4, the optical communication system according to claim 4 of the present invention comprises a wavelength multiplexer / demultiplexer 4 _n on the optical signal input side of the optical line 1 _n at the end of each group 8 of claim 2. Output terminal 9
Is the measurement point.

The optical communication system of a fifth aspect of the present invention as shown in FIG. 5, an optical light signal of two or more possible transmission line 1 _1, 1 ₂ ... of the optical signal input 2 _1, 2 ₂ , the input side waveguide component 14 is arranged, the output side waveguide component 18 is arranged at the optical signal output side, and the optical waveguide 11 of the input side waveguide component 14 is arranged.
₁ and 11 ₂ ... and directional couplers 12 ₁ and 12 ₂ ...
And the mirror waveguides 13 ₁ , 13 ₂ ... Connect the optical signal input sides 2 ₁ , 2 ₂ ... of the optical lines 1 ₁ , 12 _2, ... 18 optical waveguides 15
₁ , 15 ₂ ... And directional couplers 16 ₁ , 16 ₂ ...
And by a mirror waveguide 17 _1, 17 ₂ ..., the optical line ₁ 1, 1 ₂ ... of the optical signal output by connecting in a loop, the optical line ₁ 1, 1 ₂ ... connected to a series, to each of the directional coupler 12 _n in the optical waveguide 11 _n of the directional coupler 12 ₁ and the terminal side in the optical waveguide 11 ₁ of the starting end of the input waveguide part 14, a specific wavelength lambda ₁ Ports 21 and 22 are provided via directional couplers 19 and 20 for demultiplexing only.

[0013]

In the optical line according to claim 1 of the present invention, two or more optical lines are provided.
Light line 1₁ 1₂ Optical signal input side 2 of₁ Two₂ ・ ・
.. and optical signal output side 3₁ Three₂ ..., optical line 1₁ 1
₂ ... wavelength division multiplexer / demultiplexer 4 to form a series of loops
₁ Four₂ Two or more are connected by the connector 5 via
Optical line 1₁ 1₂ Optical path 1 on the starting side₁ of
Optical signal input side 2₁ Wavelength multiplexer / demultiplexer 4₁ Input and output monitoring light
A possible port 6 is provided and the optical line 1 on the terminal side_n Optical signal of
Power side 3_n Wavelength multiplexer / demultiplexer 4_n Input from port 6
Since the port 7 for outputting the monitored light is output,
First input from TDR to one port (eg 6)
Optical line 1₁ The monitoring light input to the same optical line 1₁ From
Second, third ... Optical line 1₂ 1₃ Sequentially transmitted to ...
The reflected light of the monitoring light is measured by OTDR.
More optical lines 1₁ 1₂ Monitoring for abnormalities
You can

In the optical line of claim 2 of the present invention, the two or more optical lines 1 ₁ , 1 _2, ... Are divided into two or more groups 8 and the two or more optical lines 1 ₁ , 1 of each group 8 are divided. ₂ ... Optical signal input side 2 ₁ , 2 ₂ ... And optical signal output side 3 ₁ , 3
₂ are connected by the connector 5 via 4 ₁ , 4 ₂ so that the optical lines 1 ₁ , 1 ₂ ... Form a series of loops. When monitoring light of a single wavelength is sent to the input port 6 from one light source (for example, OTDR), the monitoring light of each group 8 is transmitted to the first optical line 1
Sequentially transmitted from the ₁ to the 2, 3 of the optical line 1 _2, 1 _3, ..., a number of optical line ₁ 1 by measuring the monitor light of the return light at that time in OTDR, 1 ₂ ·・ ・ Abnormality can be monitored.

In the optical line of claim 3 of the present invention, the output end 9 of the wavelength multiplexer / demultiplexer 4 _n on the optical signal input side of the optical line 1 _n at the end of each group 8 is a total reflection end. When the monitoring light of a single wavelength is sent to the input port 6 from one light source (OTDR, for example) for each group 8, each group 6
Monitoring light is sequentially transmitted from the first optical line 1 ₁ to the _second , ₃ ... Optical lines 1 ₂ , 1 ₃ ... Return light is measured by OTDR,
A large number of optical lines 1 ₁ , 1 ₂ ... Can be monitored. Further, since the monitoring light that has reached the total reflection end is reflected there, the amount of reflection returning to the OTDR provided on the input side increases and the position measurement of the line end becomes reliable.

In the optical line of claim 4 of the present invention, the output end 9 of the wavelength multiplexer / demultiplexer 4 _n on the optical signal input side of the terminal optical line 1 _n of each group 6 of claim 2 is used as the measurement point. So
When the monitoring light of a single wavelength is sent to the input port 6 from one light source (OTDR, for example) for each group 8, the monitoring light of each group 6 is transmitted from the first optical line 1 ₁ to the second 3 ...
· A are sequentially transmitted to the optical line 1 _2, 1 ₃ ..., then the optical line 1 _2, 1 ₃ amount of monitoring light reflected and scattered by ... are wavelength division multiplexer 2 output 9 Measured at. From the change in the amount of light, the optical lines 1 ₂ of each group 8,
It is possible to monitor 1 ₃ ...

In the optical line of claim 5 of the present invention, the optical signal input sides 2 ₁ , 2 ₂ of the two or more optical lines 1 ₁ , 1 _2, ...
, And the output side waveguide component 18 is arranged on the optical signal output side, and the optical waveguides 11 ₁ , 11 _{2 of} the input side waveguide component 14 and the directional coupler 12 are arranged. _One , one
By a 2 ₂ ... and the mirror waveguide 13 _1, 13 ₂ ..., optical line ₁ 1, 1 ₂ ... of the optical signal input 2 _1, 2 ₂
... are connected in a loop, and the optical waveguides 15 ₁ , 15 _{2 of} the output side waveguide component 18 and the directional couplers 16 ₁ , 1 are connected.
6 by a _2, ... and the mirror waveguide 17 _1, 17 ₂ ..., by connecting the optical line ₁ 1, 1 ₂ ... of the optical signal output to the loop, the optical line ₁ 1, 1 ₂ ... connected to a series, to each of the directional coupler 12 _n in the optical waveguide 11 _n of the directional coupler 12 ₁ and the terminal side in the optical waveguide 11 ₁ of the starting end of the input waveguide part 14 , Port 2 via directional couplers 19 and 20 for demultiplexing only specific wavelength λ _1.
1 and 22 are provided, the input light (the optical signal for communication and the monitoring light of the specific wavelength λ ₁ are mixed from _one of the two ports 21 and 22 (for example, 21)). From the above, only the monitoring light is separated by the directional coupler (for example, 19) of the input-side waveguide component 14, which is the directional coupler 12 of the same waveguide component 14 and the optical waveguide 1.
Entering through 1 into the optical line 1 _1. And the optical line 1 ₁
At the far end (output side) of the output side waveguide component 18 is input to the directional coupler 16 and the directional coupler 16 separates the monitoring light λ ₁ of a specific wavelength. The optical path is changed by the mirror waveguide 17 of 18 and is input to the _second optical line 1 ₂ through the directional coupler 16 of the same waveguide component 18.

The monitoring light input to the _second optical line 12 as described above is input to the optical waveguide 11 of the input side waveguide component 14 and the directional coupler 12, and is guided to the mirror of the same waveguide component 14. The optical path is changed by the waveguide 13 and is sent out to the _third optical line 1 ₃ through the directional coupler 12 of the same waveguide component 14. Hereinafter, by repeating this, the optical line 1 at which the monitoring light is terminated
_The monitoring light transmitted up to _n is sent from the directional coupler 12 _n in the optical waveguide 11 _{n at} the end of the input side waveguide component 14 to the directional coupler 20 of the same waveguide component 14, and then output through the port 22. To be done.

In the above description, the input light is input from the port 21, but in FIG. 5, the input light may be input from the port 22 and output from the other port 21 on the contrary. In any case, if the monitoring light is made incident on any one of the ports 21 or 22 from the OTDR and the return light is measured at the other port 22 by the OTDR,
It is possible to monitor the state of the optical lines 1 ₁ , 1 _2, ... And confirm the state after the break point.

[0020]

First Embodiment FIG. 1 shows a first embodiment of the optical communication device of the present invention.
It will be described in detail based on. Fig. 1 shows optical lines 1 ₁ 1 ₂
.. is the case of 4 cores, and the optical lines 1 ₁ , 1 _{2 of the} 4 cores
... can be monitored by monitoring light of a single wavelength from one light source.

[0021] In FIG 1 4-core optical line 1 _1, 1 ₂ the first optical signal output 3 ₁ optical line 1 _one of ... the second optical line 1 ₂ of the optical signal output-side 3 ₂ And WDM (optical multiplexer / demultiplexer) 4
_2, 4 ₃ are connected in a loop by coupling element 5 through the second optical line 1 ₂ of the optical signal input 2 ₂ and the third optical line 1 ₃
Of an optical signal input 2 ₃ are connected in a loop by coupling element 5 via the WDM4 _{4, 4 5,} and the third optical signal output 3 ₃ optical line 1 ₃ of the fourth optical line 1 ₄ The optical signal output side 3 ₄ is connected in a loop by a connector 5 via WDM 4 ₆ and 4 ₇ , and further the optical signal input sides 2 ₁ and 2 _{4 of} the first and fourth optical lines 1 ₁ and 1 ₄ are connected. demultiplexer 4 _1, 4 connect _n (4 _8), its optical multiplexer 4 ₁ port 6 capable of inputting and outputting monitor light is provided, the optical line 1 ₁ of the optical signal output side of the terminal end The wavelength multiplexer / demultiplexer 4 ₈ is provided with a port 7 for outputting the monitoring light input from the port 6.

[0022]

[Example of use of the first embodiment] When the optical lines 1 ₁ , 1 _2, ... Of FIG. 1 are monitored by insertion loss, light of wavelength λ ₁ is input to one port 6 and the other port 7 is used. By measuring the optical power, the optical line 1 ₁ ,
It is possible to determine the abnormality (fault) of 1 ₂ ... In this case, although it is possible to determine that an abnormality somewhere in the optical line 1 _1, 1 _2, ... is generated, which abnormality in the optical path can not be determined whether it has occurred.

The monitoring of the optical lines 1 ₁ , 1 _2, ...
In the case of TDR, an optical pulse of a specific wavelength λ ₁ is input from OTDR to one port 6, and then the optical line 1
_The return light reflected / scattered from ₁ , 1, ₂ ...
If measured by DR, the optical line 1
_{It is} also possible to specify the occurrence of anomalies such as ₁ , 1, ₂ ... In this case, the measurement wavelength λ ₁ is, for example, 1.65 μm, but other wavelengths can be used.

In FIG. 1, the optical line 1 on the start side of the signal light is used.
By inputting from either the optical signal input side 2 ₁ or 2 ₄ of the optical line 1 ₄ on the side of ₁ or the end side, four optical lines 1 ₁ , 1 ₂ ... Connected in series in a loop. Are transmitted in sequence.

[0025]

Second Embodiment A second embodiment of the optical communication device of the present invention is shown in FIG.
It will be described in detail based on. FIG. 2 shows an optical communication system with a star configuration, in which one signal light is split into two optical couplers 1.
Divide into 4 stages at 0 (2 × 8), and use 8-core optical lines 1 ₁ , 1 ₂
... can be transmitted to each.

In the case of FIG. 2 as in the case of FIG. 1, the optical signal output side 3 ₁ of the _first optical line 1 ₁ out of the 8-core optical lines 1 ₁ , 1 _2, ... road 1 ₂ optical signal output 3 ₂ and a WDM (demultiplexer) 4 _2, 4 ₃ are connected in a loop by coupling element 5 through the second optical line 1 ₂ of the optical signal input 2 ₂ and the third of the optical signal input 2 ₃ optical line 1 ₃ WD
Loops are connected by a connector 5 via M4 ₄ , 4 ₅ , and thereafter, by repeating this, 8-core optical lines 1 ₁ , 1 ₂ ,
· Connects to a series in a loop, and further, a wavelength demultiplexer 4 ₁ optical line 1 ₁ of the optical signal input 2 ₁ start end side, the optical line 1 _n the terminating optical signal output 3 _n wavelength multiplexer / demultiplexer 4 _n
In addition, ports 6 and 7 capable of inputting and outputting only the monitoring light of the specific wavelength λ ₁ are provided.

[0027]

[Example of use of embodiment 2] When abnormality monitoring of the optical lines 1 ₁ , 1 ₂ ... In FIG. 2 is performed by OTDR, an optical pulse of a specific wavelength λ ₁ from the OTDR is input to one port 6. ,
From the optical line 1 ₁ on the starting end side to the second and third optical lines 1 ₂ , 1 ₃
... through the optical line 1 _n on the terminal side. At this time, the return light reflected / scattered from the optical lines 1 ₁ , 1 ₂ ... Is measured by the OTDR, and the abnormality of the optical line and the abnormal portion of the optical line where the abnormality occurs are measured based on the measured value. You can monitor. In this case, the specific wavelength λ
For example, 1.65 .mu.m was used for ₁ , but other wavelengths can be used.

In FIG. 2, one signal light is branched into two by the optical coupler 10 in the first stage, and thereafter, is branched into two by the optical coupler 21 in the second to fourth stages, and the optical line 1 of 8 cores is formed.
It is transmitted to each of ₁ , 1, ₂ ...

[0029]

Third Embodiment A third embodiment of the present invention will be described in detail with reference to FIG. This is an 8-core optical line 1 ₁ as shown in FIG.
If 1 ₂ ... Is connected in a loop in series and the line length becomes too long and exceeds the OTDR measurement limit, it is divided into 2 blocks 8 by 4 cores, and each block 8
Is provided with an input port 6 and the other end 9 is a total reflection end.

[0030]

[Example of use of the third embodiment] When the abnormality monitoring of the optical lines 1 ₁ , 1 _2, ... Of FIG. 3 is performed by the OTDR, an optical pulse of a specific wavelength λ _{1 is} output from the OTDR provided at the port 6 of each block 8. , Then the optical line 1 of each block 8
_The return light reflected and scattered from ₁ , 1, ₂ ...
By measuring with TDR, it is possible to confirm the occurrence of an abnormality and the abnormal portion of the optical lines 1 ₁ , 1 _2, ... Of each block 8. In this case, since the other end 9 of each block 8 is a total reflection end, the amount of light returning to the OTDR increases due to reflection at the other end 9.

[0031]

[Fourth Embodiment] A fourth embodiment of the present invention will be described in detail with reference to FIG. This is also an 8-core optical line 1 ₁ , 1 as shown in FIG.
_{If 2} ... is connected in series in a loop, and the line length becomes too long and exceeds the measurement limit of OTDR, it is divided into 2 blocks 8 by 4 cores, and each block 8 has an input port 6 Is provided, and the other end 9 is used as a measurement point.

[0032]

[Example of use of Embodiment 4] When the abnormality monitoring of the optical lines 1 ₁ , 1 _2, ... Of FIG. 4 is performed by insertion loss, an optical pulse of a specific wavelength λ ₁ is input from the port 6 of each block 8. , The amount of light output from the other end (measurement point) 9 through the optical lines 1 ₁ , 1 _2, ... Of each block 8 is measured at the other end (measurement point) 9, Block 8
It is possible to monitor the abnormalities of the optical lines 1 ₁ , 1 _2, ...

In both cases of FIG. 3 and FIG. 4, one optical signal is branched into two by the optical coupler 21 in the first stage as in the case of FIG. 2, and thereafter the optical coupler 10 in the second to fourth stages is used. Are sequentially branched into two and transmitted to the eight optical lines 1 ₁ , 1 _2, ...

[0034]

Fifth Embodiment A fifth embodiment of the present invention will be described in detail with reference to FIG. This is an example in the case where there are two cores of signal light input, and moreover, a waveguide type component is used.

Reference numeral 14 in FIG. 5 is an input side waveguide component, which is composed of two or more optical lines 1 ₁ , 1 ₂ ...
Are arranged on the optical signal input side, and two or more optical waveguides 11 ₁ , 11 _2, ... And respective optical waveguides 11 ₁ , 11
And ₂ directional coupler 12 ₁ for demultiplexing only a specific wavelength lambda ₁ provided ..., 12 ₂ ..., mirror waveguide 13
₁ , 13 ₂ ..., a large number of optical couplers 10, a wavelength flat coupler 23, and directional couplers 19 and 20 for demultiplexing only a specific wavelength λ ₁ . The directional couplers 19 and 20 are provided with input terminals 21 and 22.

Reference numeral 18 in FIG. 5 denotes an output side waveguide component, which is arranged on the optical signal output side of two or more optical lines 1 ₁ , 1 ₂ ... And has two or more optical waveguides 15 ₁ . 15 ₂ ...
- and, a directional coupler 16 ₁ for demultiplexing only a specific wavelength lambda ₁ which is provided on the optical waveguide 15 _1, 15 ₂ ... each, 1
6 ₂ ... and mirror waveguides 17 ₁ , 17 ₂ ...

The second directional coupler 12 ₂ and the third directional coupler 12 _{3 of the} input side waveguide component 14 are connected in a loop by a mirror waveguide 13 ₁ provided therebetween, and Similarly, the fourth directional coupler 12 ₄ and the fifth directional coupler 12 ₅ are coupled to each other by the mirror waveguide 13 ₂ to form the sixth directional coupler 12 ₆ and the seventh directional coupler 12 _7. And are sequentially connected in a loop by a mirror waveguide 13 ₃ .

The first directional coupler 16 ₁ and the second directional coupler 16 _{2 of the} output side waveguide component 18 are connected in a loop by a mirror waveguide 17 ₁ provided therebetween, and Similarly, the third directional coupler 16 ₃ and the fourth directional coupler 16 ₄ are connected to the fifth directional coupler 16 ₂ by the mirror waveguide 17 ₂ .
The directional coupler 16 ₅ and the sixth directional coupler 16 ₆ are connected by the mirror waveguide 17 ₃ to the seventh directional coupler 16 ₇
And the eighth directional coupler 16 ₈ are sequentially connected in a loop by a mirror waveguide 17 ₃ .

[0039] Then, the optical waveguide 11 ₁ of the input waveguide parts 14, 11 ₂ ... and the output side waveguide component 15
_1, 15 by connecting the optical line ₁ 1, 1 _2, ... between the ₂ ..., optical line ₁ 1, 1 _2, ... is coupled to the series.

[0040]

[Example of use of the fifth embodiment] When abnormality monitoring of the optical lines 1 ₁ , 1 _2, ... Of FIG.
The input light in which the optical signal for communication and the monitoring light of the specific wavelength λ ₁ are mixed is input from either one of 1 and 22 (for example, 21). Only the monitoring light is separated from this input light by the directional coupler (for example, 19) of the input side waveguide component 14, which is the directional coupler 12 _{1 of the} input side waveguide component 14.
When input to the optical line 1 ₁ through the optical line 1 ₁ , the directional coupler 16 ₁ of the output-side waveguide component 18 at the far end of the optical line 1 ₁ splits the monitoring light λ ₁ of a specific wavelength, The optical path is changed by the mirror waveguide 17 ₁ and is input to the _second optical line 1 ₂ through the directional coupler 16 ₂ of the waveguide component 18. The supervisory light transmitted to the terminal optical line 1 _n in this way is the terminal optical waveguide 11 _n of the input side waveguide component 14.
From the directional coupler 12 _n of the same to the directional coupler 20 of the same waveguide component 14 and then output through the port 22.

In FIG. 5, contrary to the above case, the port 22
When the input light is input from, the monitoring light included in the input light is transmitted in the opposite direction to the above case. Therefore, if the input light is input from one of the ports 21 or 22 from the OTDR and the reflected light is measured by the OTDR at the one port 22, the state of the optical line is monitored and the state after the break point is confirmed. can do.

In FIG. 5, when the input light is made incident on the port 21 or 22, the optical signal contained therein reaches the wavelength flat coupler 23 through the directional coupler 19 and is branched into two. Are branched into two, and the respective optical lines 1 ₁ , 1 _{2 are} passed through the respective optical waveguides 11 ₁ , 11 _2, ...
Is transmitted to.

[0043]

The optical communication system according to claims 1 to 5 of the present invention has the following effects. ． Since it is possible to simultaneously monitor a large number of optical lines with a single wavelength from a single light source, it is possible to easily monitor a large number of optical lines with a simple configuration. ． It is convenient for maintenance because it is possible to monitor abnormalities of two or more optical lines at the same time and to confirm where in the two or more optical lines the abnormality has occurred. ． Since it is possible to monitor abnormalities in two or more optical lines at the same time, it is possible to reduce the number of times of measurement and time, and it is possible to efficiently monitor a large number of optical lines. ． Since it can be used for monitoring an optical communication system having various configurations such as a star configuration and a double star configuration, it has a wide range of applications and is convenient.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of an optical communication system of the present invention.

FIG. 2 is an explanatory diagram showing a second embodiment of the optical communication system of the present invention.

FIG. 3 is an explanatory diagram showing a third embodiment of the optical communication system of the present invention.

FIG. 4 is an explanatory diagram showing a fourth embodiment of the optical communication system of the present invention.

FIG. 5 is an explanatory diagram showing a fifth embodiment of the optical communication system of the present invention.

FIG. 6 is an explanatory diagram showing an example of a conventional optical communication system.

FIG. 7 is an explanatory diagram showing another example of a conventional optical communication system.

[Explanation of symbols]

1 ₁ , 1 ₂ ... Optical line 2 ₁ , 2 ₂ ... Optical signal input side 3 ₁ , 3 ₂ ... Optical signal output side 4 ₁ , 4 ₂ ... Wavelength multiplexer / demultiplexer 6, 7 Ports 11 and 15 Optical waveguide 12 Directional coupler 13 Mirror waveguide 14 Input side waveguide component 16 Directional coupler 17 Mirror waveguide 18 Output side waveguide component 19 and 20 Directional coupler 21 and 22 ports

Claims (5)

[Claims] 1. A plurality of optical lines (1) capable of transmitting an optical signal.
₁ , 1, ₂ ...) Optical signal input side (2 ₁ , 2 ₂ ...)
And the optical signal output side (3 ₁ , 3 _2, ...)
₁ , 1 ₂ ...) are connected by a coupler (5) through a wavelength multiplexer / demultiplexer (4 ₁ , 4 ₂ ...) to form a series of loops, and two or more optical lines ( 1 _1, 1 ₂ optical signal input side of ...) the starting side of the optical line of the (1 ₁₎ (2 ₁₎ of the wavelength division multiplexer (4 ₁₎ to the input and output enable port monitoring light (6 )
The provided optical signal output side of the terminal end side of the optical line (1 _n) (3
an optical communication system, wherein said that the monitoring light input from the port (6) is provided with a port (7) to be output to the wavelength division multiplexer (4 _n) of the _n). 2. The two or more optical lines (1 ₁ , 1 ₂ ) according to claim 1.
...) is divided into two or more groups (8), and the optical signal input sides (2 ₁ , 2 ₂ ...) Of the two or more optical lines (1 ₁ , 1 ₂ ...) Of each group (8). ) And the optical signal output side (3 ₁ , 3
₂ ...) are connected by a connector (5) via (4 ₁ , 4 ₂ ...) so that the optical lines (1 ₁ , 1 ₂ ...) form a series of loops. An optical communication system characterized by the following. 3. All the output terminals (9) of the wavelength multiplexer / demultiplexer (4 _n ) on the optical signal input side (2 _n ) of the optical line (1 _n ) at the end of each group (8) of claim 2. An optical communication system characterized in that it serves as a reflecting end. 4. The output terminal (9) of the wavelength multiplexer / demultiplexer (4 _n ) on the optical signal input side (2 _n ) of the optical line (1 _n ) at the end of each group (8) according to claim 2. An optical communication system characterized by being points. 5. A plurality of optical lines (1) capable of transmitting an optical signal.
₁ , 1, ₂ ...) Optical signal input side (2 ₁ , 2 ₂ ...)
The input side waveguide component (14) is arranged on the optical signal output side, and the output side waveguide component (18) is arranged on the optical signal output side.
4) optical waveguides (11 ₁ , 11 ₂ ...), directional couplers (12 ₁ , 12 ₂ ...), and mirror waveguides (13 ₁ ,
13 ₂ ...) and the optical line (1 ₁ , 1 ₂ ...)
Optical signal input sides (2 ₁ , 2 ₂ ...) Of which are connected in a loop, and the optical waveguides (15 ₁ , 1
5 ₂ ...) and a directional coupler (16 ₁ , 16 ₂ ...)
And the mirror waveguides (17 ₁ , 17 ₂ ...) Connect the optical signal output sides of the optical lines (1 ₁ , 1 ₂ ...) In a loop to form the optical lines (1 ₁ , 1 2. ₂ ...) are connected in series, and the direction in the directional coupler (12 ₁ ) in the optical waveguide (11 ₁ ) on the starting side of the input side waveguide component (14) and the direction in the optical waveguide (11 _n ) on the terminating side is Optical communication characterized in that ports (21, 22) are provided via directional couplers (19, 20) for demultiplexing only the specific wavelength λ ₁ to each of the directional couplers (12 _n ). system.