JPH11215059A - Light line testing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost necessary for the operation scuh as maintenance fee for deducing a measurement time, and to simplify a device configuration by testing many light lines with one light pulse tester at the same time. SOLUTION: Two adjacent light lines are connected gradually by the use of multiplexer/demultiplexer photo-couplers so that a 1st light line 86 and a 2nd light line 87 are connected to a multiplexer/demultiplexer photocoupler 21 at a right end, and the line 87 and a 3rd light line 88 are connected to a multiplexer/demultiplexer photocoupler 22 at a left end in plural light lines for connecting optical transmitter devices 1A and 2A, an optical pulse tester 12 is connected to the left end of the line 86 through the use of a multiplexer/ demultiplexer photocoupler 20 and each light line is tested by using only one test beam of the tester 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical line test apparatus, and more particularly, to a test such as an optical pulse test of an optical line in an optical line communication network composed of optical lines using optical fibers. The present invention relates to an optical line test device for detecting an optical line abnormality.

[0002]

2. Description of the Related Art FIG. 16 is a block diagram showing a conventional optical line test apparatus disclosed, for example, in Japanese Patent Laid-Open No. 2-1632. As shown in FIG. 16, the conventional optical line test apparatus has
Optical fiber cable 10 between optical transmission devices 101 and 102
5,106 are connected. A configuration including N / 2 (N is an integer) multiplexing / demultiplexing optical couplers 107 for controlling the insertion of test light from the outside into the optical fiber cables in the middle of the optical fiber cables 105 and 106; Generation of test wavelength light and optical fiber cables 105 and 10
And a configuration including an optical pulse tester 12 for detecting the test wavelength light returned from 6.

The multiplexing / demultiplexing optical couplers 107 are inserted at arbitrary points of the optical fiber cables 105 and 106. In addition, the configuration including the optical pulse tester 12 performs, in addition to the optical pulse tester 12, a 1XN optical switch 110 for selecting a test line port of the multiplexing / demultiplexing optical coupler 107, and program control of the 1XN optical switch 110. Control device 114
And a display device 115 for performing display.

Next, the operation will be described. In the optical line test apparatus shown in FIG. 16, the test light output from the optical pulse tester 12 is input to a 1 × N optical switch 110, and this optical switch 110 is connected to an external control device 11
4, the test light is guided to the test light insertion optical fibers 109, 108,... Connected to a predetermined optical line. The test light is the 1 / N optical switch 110
, And is input to the optical line by the multiplexing / demultiplexing optical coupler 107.

[0005]

Since the conventional optical line test apparatus is configured as described above, the following problems occur. (1) Since the 1 × N optical switches 105 and 106 are introduced, the cost and the operational cost of the optical line test are high. (2) When testing a large number of optical lines, one optical line
Since the measurement is performed after the individual selection, it takes an enormous amount of time to measure the entire optical line. (3) In order to test a large number of optical lines, it is necessary to provide a large number of ports of the optical switch, so that the structure is complicated.

The present invention solves the above-mentioned problems of the prior art by providing a plurality of optical transmission lines on the premise of reducing operational costs such as maintenance, shortening measurement time, simplifying a device configuration, and the like. It is an object of the present invention to obtain an optical line test apparatus capable of performing a test on the optical line almost simultaneously.

[0007]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, an optical line test apparatus according to the present invention connects a first and a second optical transmission device for transmitting and receiving communication light with a plurality of optical lines, and connects the first and second optical transmission devices to the plurality of optical lines. In an optical line test apparatus for transmitting a test light having a wavelength different from that for use and performing an optical line test, each optical line is connected to two optical lines adjacent to each optical line. One of the two optical transmission lines is coupled to one end of the first optical transmission device, and the other adjacent optical line is coupled to the other end of the second optical transmission device. A plurality of multiplexing / demultiplexing means for branching and transmitting only the test light and the reflected light thereof between the optical path and the other optical line, and coupled to a head optical line of the plurality of optical lines,
Test means for branching only the test light and its reflected light from the leading optical line as a base point and testing each of the optical lines.

According to the present invention, since only the test light is coupled to the adjacent optical line starting from the first optical line among the plurality of optical lines, each optical line is tested. Each optical line can be tested almost simultaneously using only light, thereby making it possible to reduce operational costs such as maintenance, shorten measurement time, simplify the device configuration, and the like.

In the optical line testing apparatus according to the next invention, the first and second optical transmission devices for transmitting and receiving communication light are connected by a plurality of optical lines, and the communication light is connected to the plurality of optical lines. An optical line test apparatus that transmits a test light having a wavelength different from that of the optical line and performs an optical line test, wherein each of the optical lines is adjacent to one of the two adjacent optical lines. One end on the first optical transmission device side is coupled to the optical line, and the other end on the second optical transmission device side is coupled to the other adjacent optical line. A plurality of multiplexing / demultiplexing means for branching and transmitting only the test light and the reflected light thereof with the other optical line, and being coupled to a first optical line of the plurality of optical lines, The test light and its reflected light are branched from the path as a starting point, and Test means, and one or more amplifying means provided at a required portion of an optical path including the optical line and the multiplexing / demultiplexing means, and amplifying at least the transmitted test light. It is characterized by having.

According to the present invention, only the test light is coupled to the adjacent optical line with the leading optical line as a base point among the plurality of optical lines, and the light is amplified at a required portion of the optical path and each light beam is amplified. Since the test is performed on each optical path, not only can each optical line be tested almost simultaneously using only one test light, but also more optical lines can be tested by compensating for the optical transmission loss of the test light. As a result, it is possible to reduce the operational costs such as maintenance, shorten the measurement time, and simplify the device configuration.

In the optical line testing apparatus according to the next invention, the amplifying means provided on the optical line includes a detour for preventing reflected light traveling in a direction opposite to the traveling direction of the test light from passing through an amplification path. It has a road.

According to this invention, the reflected light propagating in the direction opposite to the traveling direction of the test light is allowed to pass through without being amplified by the detour, so that the reflected light traveling in the traveling direction of the test light is located downstream of the optical amplification path. Optical lines can also be tested.

[0013] In the optical line testing apparatus according to the next invention, the test means is connected to the first optical line in the first optical transmission device, and the coupling unit coupled to one end of each of the optical lines. The wave means is provided in the first optical transmission device, while the multiplexing / demultiplexing means coupled to the other end of each of the optical lines is provided in the second optical transmission device.

According to the present invention, the multiplexing / demultiplexing means coupled to one end of each optical line is provided in the first optical transmission device, while the multiplexing / demultiplexing means coupled to the other end of each optical line is provided in the first optical transmission device. (2) Since the optical transmission device is provided in the optical transmission device, the test can be performed from the end of the optical line, whereby it is possible to know the optical transmission loss over almost the entire length of the external optical line from each optical transmission device. is there.

In the optical line testing apparatus according to the next invention, the plurality of optical lines coupling the first and second optical transmission devices may include a test associated with an optical path length including the optical line and the multiplexing / demultiplexing means. Is divided into a plurality of sets according to the dynamic range of the test light, and the test means selectively switches the set of optical paths to be tested, and sets the test light and its reflected light only between the switched set. Characterized by having a switch for passing

According to the present invention, the optical line is divided into a plurality of sets according to the dynamic range of the test accompanying the optical path length, and the set of the optical lines to be tested is selectively switched by the switch. Therefore, no matter which optical line set is selected, the optical transmission loss is kept low and the dynamic range of the test is not exceeded. It is possible to implement.

In the optical line testing apparatus according to the next invention, the test means comprises: first and second paths that are respectively coupled to the first and last optical lines of the plurality of optical lines; A switch that selectively switches one of the first and second paths according to a traveling direction when the test light is made to pass, and that passes the test light and the reflected light thereof on the switched path. And

According to the present invention, the traveling direction (path) of the test light is selectively switched by the switch, and the test is performed in the traveling direction. The test light can be made to travel from any direction toward the position, so that even if a failure occurs at any position on the line, all the optical lines can be tested.

In the optical line test apparatus according to the next invention, a plurality of optical transmission devices for transmitting and receiving communication light are connected by a plurality of optical lines, and the plurality of optical lines are different from the communication light. In an optical line test apparatus for transmitting a test light having a wavelength and performing an optical line test, a test communication control device for performing a test and communication at each end of the plurality of optical lines is connected one by one, Each test communication control device is connected to each of the optical lines, and a plurality of multiplexing / demultiplexing means for branching and transmitting only light having the same wavelength as the test light to and from each of the optical lines, Communication communication light having the same wavelength as that of the optical communication device, and test communication means for performing test communication with the partner test communication control device through the respective multiplexing / demultiplexing means and the connected optical lines. Features.

According to the present invention, a plurality of test communication control devices are connected to the line, and the communication light handled by the test communication control device is set to the same wavelength as the test light to perform the test communication of the optical line. The communication light used for test communication does not affect the normal communication light handled by the optical transmission device, and the optical communication network can be expanded using the test communication control device as a node. It is possible to perform an optical line test of a simple optical line network from a certain terminal.

In the optical line testing apparatus according to the next invention, the test communication unit inserts a predetermined pattern when transmitting the communication light when the transmission side is set, and when the test communication unit is the reception side. When the communication light is received, the bit error rate is measured based on the inserted predetermined pattern, and each of the test communication control devices determines whether the optical line is normal / uncorrected according to the measured bit error rate. It is characterized in that an abnormality is judged and a test of the optical line is controlled when a result of the judgment is obtained.

According to this invention, when a predetermined pattern inserted in the communication light having the same wavelength as the test light in the test communication control device on the transmitting side is received by the test communication control device on the receiving side, the reception Since the test of the optical line is performed when an abnormality is confirmed from the bit error rate of the predetermined pattern, the test of the optical line can be automatically performed according to the state of the optical line. is there.

In the optical line test apparatus according to the next invention, each of the test communication control devices has an external interface section that controls an interface with a higher-level device. When it is obtained, the abnormality is notified to the host device through the external interface unit.

According to the present invention, in each test communication control device, when a determination result of abnormality is obtained in the determination of normal / abnormal, the abnormality is notified to the upper-level device via the external interface unit. Therefore, if a large number of test communication control devices are provided in the optical line network, a large-scale automatic monitoring of the optical line network can be performed, thereby greatly reducing the maintenance cost of the optical line.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the optical line test apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 FIG. First, the configuration will be described. FIG. 1 is a block diagram showing an optical line test apparatus according to Embodiment 1 of the present invention. For example, as shown in FIG. 1, this optical line test device includes N optical lines 86, 87, and 8 that connect the optical transmission devices 1A and 2A and the optical transmission devices 1A and 2A.
8, the optical fiber cable 31, each optical line 86,
Are coupled to the multiplexing / demultiplexing optical couplers 21, 22, 23..., Which are means for coupling the test wavelength light to 87, 88. The optical pulse tester 12 measures the optical transmission loss of the optical line by the reflected light.

Each of the optical transmission apparatuses 1A and 2A has N optical transmission / reception units 5 and N optical connectors 35 corresponding to the optical transmission / reception units 5 respectively. Also, the optical line 86,
87, 88... Multiplex / demultiplex optical couplers 20, 22,.
Optical connectors 35 are also provided on the side of the optical transmission device 2A.
On the other hand, the optical transmission device 1A of the multiplexing / demultiplexing optical couplers 21, 23,.
Optical connectors 35 are also provided on the side.

Next, the operation will be described. In the above configuration, each optical line 8 in the optical fiber cable 31
The test light emitted from the optical pulse tester 12 is coupled to the ends of 6, 87, 88,.
23 are connected to the ends of different optical lines. That is, the test light emitted from the optical pulse tester 12 is first guided to the first optical line 86 by the first multiplex / demultiplex optical coupler 20.

The test light propagates over substantially the entire length of the first optical line 86, and guides the test light provided in front of the optical transmission device 2 from the end to the second optical line 87 below. Are transmitted through the multiplexing / demultiplexing optical coupler 22. This test light is guided to the second optical line 87, propagates through the second optical line 87, passes therethrough, and is guided to the third multi / demultiplex optical coupler 22 provided in front of the optical transmission device 1. Further, the test light passes through the third optical line 88, and thereafter propagates in the optical lines that are sequentially coupled in the same flow.

The optical paths 86, 87, 88,...
Are made of the same material, cause Rayleigh scattering in each part, and travel in the opposite direction as reflected light. For example, the third optical line 88
The light reflected by a certain portion is propagated to the upper second optical line 87 by the multiplexing / demultiplexing optical coupler 22 and further to the upper first optical line 87.
Of the optical pulse tester 1
2 is input. Thus, the optical transmission loss in the optical line can be known.

Next, the flow of light in the multi / demultiplex optical coupler 20 will be described. FIG. 2 is a diagram for explaining input and output of the multiplexing / demultiplexing optical coupler 20 according to the first embodiment. In the figure, λ0, λ1, and λ2 indicate lights having different wavelengths, respectively, and 41, 42, 43, and 44 indicate ports, respectively.

First, the light λ0 input as test light from the port 41 travels to the port 43 with almost no loss.
Conversely, the light λ0 input from the port 43
Progress with little loss. Further, the lights λ1 and λ2 input from the port 44 travel to the port 43 with little loss, and the lights λ1 and λ2 input from the port 43 travel to the port 41 with little loss. Therefore, by inputting the light λ0 as test light from the port 41 and using the lights λ1 and λ2 as communication light, the test light emitted from the optical pulse tester 12 can be inserted into the optical line.

Next, the multi / demultiplex optical coupler will be described. FIG. 9 is a diagram for explaining input and output of the multiplexing / demultiplexing optical coupler according to the fourth embodiment. In the figure, 45, 46
Are the ports of the optical line 86, and 47 and 48 are the optical lines 87
Port. In addition, λ3 and λ4 are communication lights for signals.

In FIG. 9, light having wavelengths of λ1 and λ2 transmitted through the first optical line 86 is directly transmitted to the port 46.
Transmitted to the multiplexing / demultiplexing optical coupler 21 with almost no transmission in the direction of the port 46, and further transmitted to the port 4 of the second optical line 87.
8 is propagated.

Therefore, the test light λ0 emitted from the optical pulse tester 12 passes through the first optical line 86 for substantially the entire length, and is input to the second optical line 87 through the multiplexing / demultiplexing optical coupler 21. It is transmitted to its end. For this reason, the reflected light mainly due to Rayleigh scattering proceeds in the respective optical waveguide portions in the reverse direction, and does not reach the ends of the optical lines 86 and 87, and finally returns to the optical pulse tester 12.
With the above internal functions, the optical transmission loss of the optical line can be measured.

The first optical line 86 and the second optical line 8
7 can make it easier to separate the transmission loss of the first and second optical lines 86 and 87 by slightly increasing the insertion loss of the multiplexing / demultiplexing optical coupler 21. Alternatively, if the length of each installed optical line and the length of the multiplexing / demultiplexing optical coupler are known, each transmission loss can be known from the measurement data.

Next, the relationship between the distance and the optical transmission loss for the optical line will be described. FIG. 3 is a graph showing optical transmission loss with respect to distance in the first embodiment. FIG. 3 shows an example of a test result of the optical line. The horizontal axis of the graph is the distance (km) of the measured part, and the vertical axis is the optical transmission loss (dB).

In FIG. 3, the portions of the optical lines (for example, the optical lines 86, 87 and 88) are substantially straight portions (in the figure,
(A linear portion falling to the right). In addition, the optical line 8
In the portions 6, 87 and 88, the portions connected to the optical connector, the multiplexing / demultiplexing optical coupler (the multiplexing / demultiplexing optical couplers 21, 22, 23) and the optical connector are portions having a waveform that swings up and down. The optical connector 35 has a slightly higher reflection level at the connection point of the optical line,
Further, there is a connection loss due to light leakage from the connection portion.
The multiplexer / demultiplexer couplers 21, 22, and 23 have almost no insertion loss, and if there is no fault point such as a break point, the waveform becomes linear (in the figure, a downward-sloping linear portion).

Further, in order to determine the optical transmission loss of the optical line from FIG. 3, if the position of the optical line from the optical pulse tester 12 is known, the length of the optical line or the reflection or connection loss of the optical connector 35 can be used. It can be recognized from the inclination of the substantially linear portion existing between the irregular waveforms. If there is a break in the optical line, the level of the reflected light is significantly increased at that break, so that it is easy to see from FIG. 3 that there is an abnormality and that the break is also visible.

As described above, according to the first embodiment, a plurality of different optical lines are connected to the multiplexing / demultiplexing optical couplers 21.
Therefore, only the test light different from the communication light is sequentially guided to another optical line via the multiplexing / demultiplexing optical coupler. Thus, it is possible to test a plurality of optical lines almost simultaneously with one optical pulse tester 20. As a result, the measurement time can be shortened, the device configuration can be simplified, and the like.
Further, it is possible to easily find the failure position from the test result.

Embodiment 2 In the first embodiment, no mention is made of the optical transmission loss. However, as in the second embodiment described below, the test light is amplified on the path to correct the optical transmission loss. You may. In the second embodiment, since the overall configuration is the same as that of the above-described first embodiment, each different configuration is assigned a new number, and the same configuration is denoted by the same numeral. Description is omitted. Only the differences will be described below.

First, the configuration will be described. FIG. 4 is a block diagram showing an optical line test apparatus according to Embodiment 2 of the present invention. The configuration shown in FIG. 4 is entirely the same as the configuration of the first embodiment described above. As a different configuration, as shown in FIG. 4, the fiber type optical amplifier 24 provided in the multiplexing / demultiplexing optical coupler 22 and the fiber optical amplifier 24 provided near the connecting portion of the multiplexing / demultiplexing optical coupler 23 on the fourth optical line 89 from the top. That is, the added fiber type optical amplifiers 24 and 25 are added. The above fiber type optical amplifiers 25 and 26 are amplifiers capable of amplifying at least the test wavelength light.

In FIG. 1 or FIG. 3, when connecting a large number of optical lines, the number of connections such as the optical connection loss of the optical connectors 35 or the insertion loss due to the multiplexing / demultiplexing optical couplers 20, 21, 22, 23. It is likely that it will increase. Therefore, if the optical connection loss or the insertion loss is large, the absolute value of the loss increases due to the accumulation of the number of connections.
, The dynamic range that can be measured is easily exceeded. Therefore, in the second embodiment, fiber optical amplifiers 24 and 25 are introduced.

The fiber type optical amplifiers 24 and 25 are arranged at certain locations on the transmission path through which the test light passes, and amplify at least the test light among the plurality of wavelengths of light being transmitted. In FIG. 4, the fiber type optical amplifier 25 includes:
It is provided on the optical line 89 and amplifies and transmits both the communication light λ3 and λ4 and the test wavelength light λ0. However, since the fiber optical amplifier 24 is provided in the multiplexing / demultiplexing optical coupler 21. , Only the test wavelength light λ0 is amplified and transmitted.

Therefore, the fiber type optical amplifiers 24, 2
5 amplifies at least the test wavelength light,
The reflected light on the line through which the amplified test light passes is greater than that on the line without the fiber optical amplifier. Thus, the dynamic range of the optical pulse tester 12 can be prevented from being exceeded.

However, when a fiber-type optical amplifier is used (see Masatoyo Tsunoda, Shinichi Furukawa, Ikuaki Tanaka, Masaki Amemiya, "Study of fault location technology in submarine optical amplification repeater transmission system")
IEICE Transactions Vol. J78-BIN
o. 12 pp 745 to 752), since the fiber type optical amplifier has a high amplification degree, an optical isolator for preventing multiple reflection and operating stably is arranged.
Since the reflected light of the test light that has proceeded further by this isolator is cut off the path to the optical pulse tester 12, the measurement becomes impossible.

In consideration of the above, the fiber type optical amplifier 2
4 and 25 will be described in more detail. FIG. 5 is a block diagram showing a typical configuration of the fiber type optical amplifier according to the second embodiment. FIG. 5 shows a configuration of the fiber type optical amplifier 25 as a representative example. In FIG. 5, 1
Reference numerals 6 and 17 denote optical circulators for switching input and output destinations, respectively, 18 a pump light laser for amplifying light, and 49 and 5 respectively.
0 and 51 are ports of the optical circulator 16 and 5 and 5 respectively.
Reference numerals 2, 53, and 54 denote ports of the optical circulator 17, respectively, and reference numeral 89c denotes a bypass route between the optical circulators 16 and 17 that does not pass through an amplification path by the pump light laser 18.

For example, the communication light λ is
The test light λ0 is transmitted from the point a to the point b by the multiplexing / branching optical coupler 23.
Is input to the optical circulator 16. In the first optical circulator 16, as shown in FIG. 5, the light input from the port 49 is output to the port 50, the light input from the port 50 is not output, and the light input from the port 51 is output to the port 49. It will have the direction to do.

Therefore, the first optical circulator 16
The test light λ0 input to the optical fiber amplifier 25 travels into the fiber optical amplifier 25, where it is amplified and the second optical circulator 1
7 is input to port 52. This optical circulator 1
At 7, the test light λ0 is output to the port 53 due to the above-described directionality, and propagates through one optical line 89 b of the fourth optical line 89.

Here, the reflected light of the test light λ0 propagating through the optical line 89b is input to the port 53 of the second optical circulator 17 and is output to the port 54 for the above-mentioned directionality, and is output to the bypass 89c. Propagated. The above-described reflected light that has propagated through the detour 89c is input from the port 51 of the optical circulator 16 and output to the port 49.

The reflected light output from this port 49 is
The signal is input from the point b to the point a of the multi / demultiplex optical coupler 23 and then to the third optical line 88. Further, the reflected light passes through the optical line 88, the multiplexing / demultiplexing optical coupler 22, the second optical line 87, the multiplexing / demultiplexing optical coupler 21, and the first optical line 86 via the multiplexing / demultiplexing optical coupler 20 and the optical pulse tester 12. Return to. By providing the detour 89c as described above, it is possible to test the optical line after passing through the fiber type optical amplifiers 24 and 25.

Next, the relationship between the distance and the optical transmission loss for the optical line will be described. FIG. 6 is a graph showing light transmission loss with respect to distance in the second embodiment of the present invention. FIG. 6 shows an example of the test result of the optical line. The horizontal axis of the graph is the distance (km) of the measured part, and the vertical axis is the optical transmission loss (dB).

In FIG. 6, the reflected light of the test light emitted from the optical pulse tester 12 has its intensity attenuated until it reaches the optical circulator 16 at the input of the fiber type optical amplifier 24 during propagation. Go. However, in the subsequent waveform, since the test light is amplified by the fiber-type optical amplifier 24, the intensity of the reflected light increases and the loss is corrected. As a result, the waveform of the test light returns upward. By doing so, it is possible to test a larger number of optical lines.

As described above, according to the second embodiment, not only the effect of the first embodiment can be obtained, but also the fiber optical amplifier is inserted into the path of the test light. The optical amplification can compensate for the optical transmission loss of the test light, thereby making it possible to test a larger number of optical lines than in the first embodiment.

In the second embodiment, an attenuator for attenuating the intensity of light may be provided in a stage preceding the optical circulator 17 in order to adjust the amplification degree.

Embodiment 3 In the first and third embodiments, when the distance between the multiplexing / demultiplexing optical coupler and the optical transmitting / receiving unit is set to be long, it is not possible to know the optical transmission loss therebetween. As in Embodiment 3, a multiplexing / demultiplexing optical coupler is installed inside the optical transmission device,
The optical transmission loss over the entire length of the external optical line may be known.

Since the third embodiment is generally similar in structure to the first embodiment described above, each different configuration is assigned a new number, and the same configuration is assigned the same reference numeral. The description is omitted using the numbers. Only the differences will be described below.

First, the configuration will be described. FIG. 7 is a block diagram showing an optical line test apparatus according to Embodiment 3 of the present invention. In the figure, reference numerals 1B and 3 denote optical transmission devices that perform functions corresponding to the above-described optical transmission device 1, and 2B1 and 2B2.
B2 and 2B3 are optical transmission devices that perform functions corresponding to the optical transmission device 2 described above. In the first and third embodiments described above, the optical transmission device 1 and the multiplexing / demultiplexing optical coupler are provided separately, but in the third embodiment, as shown in FIG. 2B1, 2B2, 2B3, 3
A multiplexing / demultiplexing optical coupler is provided therein.

Each optical transmission device 1B, 2B1, 2B2, 2B
In 3 and 3, the optical transmitting and receiving unit 5 has a function of transmitting and receiving an optical communication signal, and the optical line interface unit 8 couples the optical line and the optical transmitting and receiving unit. Here, each optical transmission device 1B,
2B1, 2B2, 2B3, and 3 are connected to external optical lines (optical lines 86, 87, 88, 89, etc.) by an optical connector 35 using an optical line interface unit 8 that is an optical fiber.

In the optical transmission device 1B, a portion of the optical line interface section 8 includes a multiplexing / demultiplexing optical coupler 20 for inputting light emitted from the optical pulse tester 12 and the optical lines 87 and 88, that is, different optical lines. A multiplexing / demultiplexing optical coupler 22 for coupling test light therebetween is provided. Similarly, in the optical transmission devices 2B1 and 2B2, the portion of the optical line interface section 8 includes the portion between the optical lines 86 and 87,
Multiplexing / demultiplexing optical couplers 21 and 2 for coupling test light between 7, 88
3 are provided. Thus, the multiplexing / demultiplexing optical coupler 2
By disposing the optical transmission devices 1A and 2B
Measurement is possible over the entire length of the optical line between 1, 2, B2 and 2B3.

Further, when a transmission abnormality occurs in the optical line network including the optical line and the multiplexing / demultiplexing optical coupler, the inside and outside of the optical transmission device can be easily separated as the abnormal part.

Since there is a dead zone in the input / output part of the optical pulse tester 12 with respect to the optical line, which cannot be measured, there is a gap between the optical pulse tester 12 and the optical line to be tested as shown in FIG. As shown, it is desirable to use the optical fiber core 81 having a length that eliminates the dead zone.

In the case where one end is individually wired to an optical line such as a subscriber without an optical transmission device or the like, a multiplexing / demultiplexing optical coupler is provided at a terminating section of the optical cable 31 or a branching section of the cable. Can be tested over the entire length.

As shown in FIG. 7, the optical transmission devices 1 and 3 are connected to the connectors 35 and 3 by using the optical fiber 82.
By coupling at 5, it is possible to test many optical lines. In the optical transmission device 3, the optical fiber core 82
Is connected to the optical line 90 by the multiplexing / demultiplexing optical coupler 20B. The optical transmission device 3 is connected to the optical transmission device 2B3 via the optical fiber cable 32.

As described above, according to the third embodiment, the multiplexing / demultiplexing optical coupler for coupling the optical pulse tester 12 and coupling between the optical lines is not provided on the optical line side but on the optical transmission apparatus side ( Inside)
The test can be performed from the end of the optical line, and the test is performed over almost the entire length of the external optical line from the optical transmission device. Thus, it is possible to know the optical transmission loss for almost the entire length of the external optical line, and also to know the failure position from the test result as in the first embodiment.

Embodiment 4 In the third embodiment described above, the system is configured such that the injection port of the optical pulse tester 12 is one and the test light is taken in from one optical transmission device 1B. As described above, a plurality of injection ports may be provided to increase the number of optical paths that can be tested. In the fourth embodiment, since the overall configuration is the same as that of the above-described third embodiment, each different configuration is assigned a new number, and the same configuration is denoted by the same numeral. Description is omitted. Only the differences will be described below.

First, the configuration will be described. FIG. 8 is a block diagram showing an optical line test apparatus according to Embodiment 4 of the present invention. In the fourth embodiment, the optical pulse tester 1
2, an optical switch 60 is connected via an optical fiber core 83, and two outputs of the optical switch 60 are provided. One output is supplied to the optical transmission device 1 via the optical fiber core 81.
B, and the other output is connected to the connector 35 of the optical transmission device 3 via the optical fiber core wire 82.

In the optical transmission device 1B, the optical fiber core wire 82 connected to the connector 35 of the optical transmission device 3 in the third embodiment is connected to the connector 3 of the optical transmission device 1B.
5, the connector 35 of the optical transmission device 1B is preferably subjected to a non-reflection termination process.

As shown in FIG. 8, in the fourth embodiment,
1: Introduce N optical switches (N is the number of branches). Accordingly, it is possible to cope with a case where an optical line to be measured which can occur in the first, second, and third embodiments exceeds the measurement specification range (measurement length, resolution, dynamic range, etc.) of the pulse tester 12. It is possible.

Therefore, the 1: 2 optical switch 60 is provided so that either one of the first optical fiber core 81 and the second optical fiber core 82 can be selected for the test light. The selection command is issued from a control unit (not shown). At least a second optical fiber core 82
Is composed of only one optical line.

The technique according to the conventional example described above (Japanese Patent Laid-Open No.
Although a 1: N optical switch was required for N / 2 optical lines, the fourth embodiment uses the 1: N optical switch 60 to minimize the number of optical switches. It is possible to test up to N (twice the conventional) optical lines. That is, according to the fourth embodiment, even if an optical switch having the same function as that of the related art is used, it is possible to test more optical lines than before.

Next, the multi / demultiplex optical coupler will be described. FIG. 9 is a diagram for explaining input and output of the multiplexing / demultiplexing optical coupler according to the fourth embodiment. In the figure, 45, 46
Are the ports of the optical line 86, and 47 and 48 are the optical lines 87
Port. In addition, λ3 and λ4 are communication lights for signals.

In FIG. 9, light having wavelengths of λ1 and λ2 transmitted through the first optical line 86 is directly transmitted to the port 46.
Transmitted to the multiplexing / demultiplexing optical coupler 21 with almost no transmission in the direction of the port 46, and further transmitted to the port 4 of the second optical line 87.
8 is propagated.

Therefore, the test light λ0 emitted from the optical pulse tester 12 passes through the first optical line 86 for substantially the entire length, and is input to the second optical line 87 through the multiplexing / demultiplexing optical coupler 21. It is transmitted to its end. For this reason, the reflected light mainly due to Rayleigh scattering proceeds in the respective optical waveguide portions in the reverse direction, and does not reach the ends of the optical lines 86 and 87, and finally returns to the optical pulse tester 12.
With the above internal functions, the optical transmission loss of the optical line can be measured.

The first optical line 86 and the second optical line 8
7 can make it easier to separate the transmission loss of the first and second optical lines 86 and 87 by slightly increasing the insertion loss of the multiplexing / demultiplexing optical coupler 21. Alternatively, if the length of each installed optical line and the length of the multiplexing / demultiplexing optical coupler are known, each transmission loss can be known from the measurement data.

As described above, according to the fourth embodiment, the effect of the first embodiment can be obtained, and the optical switch 60 can be connected to one optical pulse tester 12.
And a plurality of output destinations are obtained therefrom, so that the number of optical lines that can be tested for one optical pulse tester can be increased.

Embodiment 5 In the first to fourth embodiments, when a failure occurs in a part of the optical path, the level and position of the failure can be specified. However, the configuration for repairing or removing the part is described. No consideration. Therefore, in order to prevent a problem that an optical line that cannot be tested for a long time appears at the time of repair or removal, the present invention provides repair or removal of a part of the optical line as in a fifth embodiment described below. In this case, the test may be performed on another optical path.

In the fifth embodiment, since the entire structure except for the connection relation is the same as that of the fourth embodiment,
Similar components are denoted by the same reference numerals and description thereof is omitted. Only the differences will be described below.

First, the configuration will be described. FIG. 10 is a block diagram showing an optical line test apparatus according to Embodiment 5 of the present invention. In FIG. 10, the above-described optical transmission device 3
In the fifth embodiment, the configuration related to this is unnecessary for explanation, and thus is omitted from the drawings. In the fourth embodiment described above, one of the two outputs of the optical switch 60 is coupled to the optical line 86 of the optical transmission device 1B, and the other is coupled to the optical line 90 of the optical transmission device 3. On the other hand, in the fifth embodiment, as shown in FIG. 10, two outputs of the optical switch 60 that make the output of the optical pulse tester 12 1: 2 are one of the optical lines of the optical transmission device 1B. 86, and the other is connected to the optical line 89 of the device 1.

That is, two outputs (test lights) from the optical switch 60 are coupled to the same optical transmission device 1B, one output flows from above to below, and the other output flows from below to above. Is injected into. That is, the configuration is such that test light can be injected from both directions in the same optical transmission device 1B.

When there is no failure in the optical fiber cable 31, one of the optical switches 60 selects the optical fiber core wire 81 and the measurement of the entire optical line is possible only by measuring from above. When a failure occurs at one of the above locations (for example, point P in FIG. 10) and the loss level is high, it may not be possible to measure beyond that point (after the optical line 87). In this case, if the optical fiber 60 on the other output end side is selected by the optical switch 60, the measurement is performed from below, and the measurement is performed before the unmeasurable portion (the optical line 87). , 88, 89).

As described above, according to the fifth embodiment, not only the effect of the fourth embodiment described above can be obtained, but also the optical switch 6 can be used until the failed part is repaired.
Since the two output ends (optical fiber core wires 81 and 82) are used, the test light can travel from any direction toward the failure position. That is, even if a failure occurs at any position on the line, it is possible to test all the optical lines and to know the position of the failure.

Embodiment 6 FIG. In the first to fifth embodiments, the test light is used only for the test of the optical line. However, as in the sixth embodiment described below, the test light is
It may be used not only for the test of the optical line but also for the communication of the optical pulse tester.

First, the configuration will be described. FIG. 11 is a block diagram showing an optical line test apparatus according to Embodiment 6 of the present invention. In the figure, reference numerals 1C and 2C denote optical transmission devices that perform the same functions as the optical transmission devices 1 and 2 of the first embodiment, respectively, and connect optical lines 91 and 92, respectively. Reference numeral 70A denotes a test communication control device for testing the optical line network of the entire optical line test device using test light, and multiplex / demultiplex optical couplers 20A and 20B are coupled to the optical lines 91 and 92, respectively.

The test communication control device 70A controls, for example, the optical transceivers 72A and 72B, the optical pulse tester 73, the optical switches 75, 76 and 77, a control unit 71 composed of an MPU, a memory and the like, a test light And an optical transceiver 72 for transmitting and receiving communication light for inter-device communication and optical line test only with the test optical path of the optical line network.
A, 72B, and an optical switch 75 for selecting one of the optical switches 76, 77 to selectively couple the test light output from the optical pulse tester 73 that emits the test light to one of the optical lines 91, 92. Communication light transmitted and received from the optical transmission / reception units 72A and 72B or the optical pulse tester 73
And optical switches 76 and 77 for selecting the test light output from the optical path and supplying the selected test light to the optical lines 91 and 92.

Next, the optical transmission / reception units 72A and 72B will be described. FIG. 12 is a block diagram showing a typical configuration of an optical transceiver according to the sixth embodiment. A typical configuration of the optical transmitting / receiving units 72A and 72B is a combination of an optical circulator 721, an optical transmitting unit 722, and an optical receiving unit 723, as shown in FIG. An LD, an LED, or the like is used for the light transmitting unit 722, and a light receiving element such as a photodiode is used for the light receiving unit 723. Since the optical circulator 721 performs transmission and reception by one optical line,
This is to determine the transmission / reception direction.

Next, the control section 14 will be described. FIG. 13 is a diagram illustrating an operation sequence of the control unit 71 according to the sixth embodiment. Here, an example is described in which a test communication control device 70A and a test communication control device 70B having the same configuration as this device 70A are connected to one optical transmission path.

First, after the test communication control devices 70A and 70B are both powered on, the test optical path of the optical line is connected to each control unit 14 in a normal state, and each control unit 14
14 is in a test request waiting state. Here, the test activation is a manual activation by a person for the test communication control device 70A.

When the test communication control device 70A issues the test request and activates the test permission confirmation timer, the test communication control device 70B receives the test request and activates the test permission issuance and test waiting timer. The connection to the communication and test lines is released. Then, in the test communication control device 70A, the selection of the optical pulse tester 73 is performed under the control of the control unit 14 for the optical switches 75, 76, and 77, and the test is performed. I do.

In the test communication control device 70B, a test waiting timer is activated due to the test waiting state, while in the test communication control device 70A, a timer for issuing a test completion notification and confirming completion notification reception is started. Test communication control device 70B
Then, a timer for waiting for test completion and a test completion confirmation is started. In the test communication control device 70A, when the test completion notification is received, if the response confirmation timer expires after the test completion notification is received, the operation returns to the normal state.

In the above operation, each of the timers except the test waiting timer and the test timer issues a test request when there is no normal notification by the time of completion of the timer or when there is an abnormal notification, and the test is permitted. The test may be performed with or without the test. If an abnormality is notified, the abnormality is notified to a higher-level monitoring device (not shown).

Further, in order to prevent the optical receiving section 723 of each of the optical transmitting / receiving sections 72A and 72B from being damaged by receiving the test light, it is necessary to consider discriminating the reception level of the communication light from the reception level of the test light. For that purpose, the optical receiving unit 723
A suitable filter may be inserted before the above, or the transmission light levels of the communication light and the test light may be adjusted.

As described above, according to the sixth embodiment, a plurality of test communication control devices are connected to the line, and the communication light handled by the test communication control device is set to the same wavelength as the test light, so that the optical communication line is controlled. Since test communication is performed, communication light used for test communication does not affect ordinary communication light handled by the optical transmission device, and the optical line network is expanded using the test communication control device as a node. be able to. As a result, it is possible to carry out an optical line test of a large-scale optical line network from a certain terminal, and in this case also, it is possible to determine a failure position from the test result.

Embodiment 7 FIG. In the sixth embodiment described above, the purpose of performing a large-scale optical line network test with one terminal, that is, a test communication control device, is described. By inserting a fixed pattern into the contents, a line having an abnormality may be automatically tested to detect the abnormality. In the seventh embodiment, since the overall configuration of the system is the same as that of the above-described sixth embodiment, a different number is assigned to each different configuration, and the same number is used for the same configuration. The description is omitted. Only the differences will be described below.

First, the configuration will be described. FIG. 14 is a block diagram showing an optical line test apparatus according to Embodiment 7 of the present invention. In FIG. 14, reference numerals 70C and 70D denote test communication control devices according to the seventh embodiment, which generally have substantially the same configuration as the test communication control device 70A according to the sixth embodiment. 3C and 3D are the optical transmission device 1 described above.
This is an optical transmission device that performs the same function as.

As in the sixth embodiment, the test communication control device 70C couples the multiplex / demultiplex optical coupler 2 to the optical lines 91 and 92 connected to the optical transmission devices 1C and 2C.
0A and 20B are combined. On the other hand, the test communication control device 7
OD is coupled to optical lines 91 and 93 connected to the optical transmission devices 3C and 4C by multiplexing / demultiplexing optical couplers 20A and 20B, respectively, so as to face the test communication control device 70C on the test optical line. You.

The sixth embodiment is different from the sixth embodiment in that an external interface unit for notifying the controller 71 of the presence or absence of an optical line abnormality as a test result to the outside is connected to the control unit 71, and a predetermined bit error rate and a predetermined bit error rate are connected to the bus 74. The difference is that a bit error rate comparison unit 79 that compares the measured value with the measured value is connected. Further, in the seventh embodiment, in addition to the configuration shown in FIG. 12, a fixed pattern insertion unit 724 for inserting a fixed pattern into communication light and a bit error of the fixed pattern are added to the optical transmitting / receiving units 72A and 72B. A bit error measuring unit 725 for measuring is provided.

Next, the operation of the control unit 71 will be described. FIG. 15 is a diagram illustrating an operation sequence of the control unit according to the seventh embodiment. In the seventh embodiment, as shown in FIG. 14, test communication control devices 70C and 70D
Are arranged to face each other through the test light path (optical paths 91, 92, 93).

Now, between the test communication control devices 70C and 70D, the fixed pattern signal is inserted into the communication light by operating the fixed pattern insertion unit 724 on the transmitting side, and the fixed pattern signal is received on the receiving side. On the receiving side, the bit error rate comparing section 79 determines the bit error rate by comparing the measurement value of the bit error measuring section 725 with a predetermined bit error rate. After transmitting the fixed pattern signal, the transmission side waits for reception of the fixed pattern signal from the other party (reception side).

At this time, the transmitting side operates the timer, during which time the fixed pattern signal is not transmitted. In addition, in order to make the timer start timings of the transmission side and the reception side different from each other, the respective devices 72, 73
An ID number is used as the identification information, and the timing of one of the transmitting and receiving sides is shifted by comparing the size of the number and the like.

In FIG. 15, test communication control device 70C
In the processing, the fixed pattern signal sent from the test communication control device 70D is received, and a process of comparing the received signal with a predetermined bit error rate serving as a reference is performed. As a result, when the bit error rate of the fixed pattern signal is higher than a predetermined bit error rate, the test communication control device 70C sends a test request to the test communication control device 70D, while the test communication control device 70D The test permission is transmitted to the test communication control device 70C.

However, in the test communication control device 70C, the test is started when the test permission confirmation timer ends even if the test communication control device 70D does not have the test permission. When the test permission signal from the test communication control device 70D is not received within the timer time, the test confirmation timer of the test communication control device 70C determines whether the test light from the test communication control device 70D comes or not. It waits for a value obtained by adding the fixed pattern reception timer.

The test communication control device 70 C
Is switched to the optical transmitting and receiving unit side, and the optical switch 77 is switched to the optical pulse tester. Thereafter, a test is performed, and the test communication control device 70C switches the optical switch 77 to the optical transmission / reception unit and sends a test completion notification to the test communication control device 70D.

If the measurement result of the test communication control device 70C is bad, or the result is reported to the test communication control device 70D or a test communication control device (not shown) connected to another port.

Further, after receiving the test completion notification, the test communication control device 70D sends a test completion notification to the test communication control device 70C. Thereafter, if the test communication control device 70D makes a test request similarly,
More accurate data, results are understood.

Further, by providing the external interface unit 78 for controlling the interface with the outside like the test communication control units 70C and 70D, it is possible to report a warning of abnormality to the outside.

Further, by providing an input terminal and providing an ID number (for example, an address number) of a test communication control device, a test request, a data request, and result data in a communication command, a different test communication control device can perform different tests. Test requests, data requests, and result data can be taken into the communication control device.

As described above, according to the seventh embodiment, the bit error rate of a signal is monitored, and a test is performed when the bit error rate exceeds a certain level (the bit error rate is low). Is normal, the abnormality of the test communication control device is notified to the upper monitoring device, while if the test result is abnormal, the abnormality of the optical line is notified to the upper monitoring device. As a result, it is possible to automatically detect an abnormality in the optical line and report an alarm to the outside, and by installing a test communication control device in more optical line networks, it is possible to automatically monitor a large-scale optical line network. It is possible to do. In this case, the maintenance cost of the optical line can be significantly reduced.

The optical fiber amplifier according to the second embodiment can be applied to the other embodiments 3 to 7, thereby compensating the optical transmission loss in each of the embodiments 3 to 7. Can be.

[0109]

As described above, according to the present invention, only the test light is coupled to an adjacent optical line from the leading optical line among a plurality of optical lines to test each optical line. As a result, each optical line can be tested almost simultaneously using only one test light, thereby reducing operation costs such as maintenance, shortening measurement time, simplifying device configuration, and the like. There is an effect that an optical line test apparatus that can be realized is obtained.

According to the next invention, only the test light is coupled to an adjacent optical line starting from the first optical line among the plurality of optical lines, and is also optically amplified at a required portion of the optical path. Since the optical lines are tested, not only can each optical line be tested almost simultaneously using only one test light, but also a larger number of optical lines can be tested by compensating for the optical transmission loss of the test light. As a result, there is an effect that an optical line test apparatus capable of realizing reduction of operation costs such as maintenance, reduction of measurement time, simplification of apparatus configuration, and the like can be obtained.

According to the next invention, the reflected light propagating in the direction opposite to the traveling direction of the test light is passed without amplifying by the detour, so that the reflected light propagating in the traveling direction of the test light is located downstream of the optical amplification path. Thus, an optical line test apparatus capable of testing even the optical line is obtained.

According to the next invention, the multiplexing / demultiplexing means coupled to one end of each optical line is provided in the first optical transmission device.
Since the multiplexing / demultiplexing means coupled to the other end of each optical line is provided in the second optical transmission device, the test can be performed from the end of the optical line. There is an effect that an optical line test apparatus capable of knowing the optical transmission loss over almost the entire length of the optical line can be obtained.

According to the next invention, the optical line is divided into a plurality of sets according to the dynamic range of the test associated with the optical path length, and the set of optical lines to be tested is selectively switched by the switch. No matter which optical line pair is selected, the optical transmission loss is kept low and the test dynamic range is not exceeded. Is obtained.

According to the next invention, the traveling direction (path) of the test light is selectively switched by the switch, and the test is performed in the traveling direction. The test light can be made to travel from either direction toward the fault position, and thus, even if a fault occurs at any position on the line, an optical line test apparatus capable of testing all the optical lines can be obtained. The effect is that it can be done.

According to the next invention, a plurality of test communication control devices are connected to the line, and the communication light handled by the test communication control device is set to the same wavelength as the test light to perform the test communication of the optical line. In addition, the communication light used for test communication does not affect the normal communication light handled by the optical transmission device, and the optical communication network can be expanded by using the test communication control device as a node. There is an effect that an optical line test apparatus capable of performing an optical line test of a large-scale optical line network from a certain terminal can be obtained.

According to the next invention, when a predetermined pattern inserted into communication light having the same wavelength as the test light is received by the test communication control device on the receiving side, the test communication control device on the receiving side receives the predetermined pattern. Since the test of the optical line is performed when an abnormality is confirmed from the bit error rate of the received predetermined pattern, the test of the optical line can be automatically performed according to the state of the optical line. This has an effect that a simple optical line test apparatus can be obtained.

According to the next invention, in each of the test communication control devices, when a determination result of abnormality is obtained in the determination of normal / abnormal, the abnormality is notified to the upper-level device via the external interface unit. Therefore, if a large number of test communication control devices are provided in the optical line network, it is possible to automatically monitor a large-scale optical line network, thereby reducing the maintenance cost of the optical line. An effect is obtained that a road test apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an optical line test apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating input and output of the multiplexing / demultiplexing optical coupler according to the first embodiment.

FIG. 3 is a graph showing optical transmission loss with respect to distance in the first embodiment of the present invention;

FIG. 4 is a block diagram showing an optical line test apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a block diagram showing a fiber type optical amplifier according to a second embodiment.

FIG. 6 is a graph showing optical transmission loss with respect to distance in a second embodiment of the present invention;

FIG. 7 is a block diagram showing an optical line test apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a block diagram showing an optical line test apparatus according to Embodiment 4 of the present invention.

FIG. 9 is a diagram for explaining input and output of the multiplexing / demultiplexing optical coupler according to the fourth embodiment.

FIG. 10 is a block diagram showing an optical line test apparatus according to Embodiment 5 of the present invention.

FIG. 11 is a block diagram showing an optical line test apparatus according to Embodiment 6 of the present invention.

FIG. 12 is a block diagram showing a configuration of an optical transceiver according to the sixth embodiment.

FIG. 13 is a diagram illustrating an operation sequence of a control unit according to the sixth embodiment.

FIG. 14 is a block diagram showing an optical line test apparatus according to Embodiment 7 of the present invention.

FIG. 15 is a diagram illustrating an operation sequence of a control unit according to the seventh embodiment.

FIG. 16 is a block diagram showing a conventional optical line test apparatus.

[Explanation of symbols]

1A, 1B, 2A, 2B1, 2B2, 2B3, 3 Optical transmission device, 12,73 optical pulse tester, 16,17 optical circulator, 18 pump optical laser, 20,20A,
20B, 21, 22, 23 multiplexing / demultiplexing optical coupler, 24,
25 fiber optical amplifier, 60 optical switch, 70
A, 70B, 70C, 70D Test communication control device, 71
Control unit, 78 external interface unit, 79 bit error rate comparison unit, 81, 82, 83 optical fiber core wire, 8
6, 87, 88, 89, 91, 92, 93 Optical line, 8
9c detour, 724 fixed pattern insertion part, 725
Bit error measurement unit.

Claims (9)

[Claims] A first and a second optical transmission device for transmitting and receiving communication light are connected by a plurality of optical lines, and test light having a wavelength different from that of the communication light is supplied to the plurality of optical lines. An optical line test apparatus for transmitting and testing an optical line, wherein each of the optical lines is connected to one of the adjacent optical lines with respect to two of the adjacent optical lines. One end on the device side is coupled, and the other end on the second optical transmission device side is coupled to the other adjacent optical line, and between the one optical line and the other optical line. A plurality of multiplexing / demultiplexing means for branching and transmitting only the test light and the reflected light thereof, coupled to a first optical line of the plurality of optical lines, and the test light and its Testing means for branching only the reflected light to test each of the optical lines. An optical line test apparatus, characterized in that: 2. A first and a second optical transmission device for transmitting and receiving communication light are connected by a plurality of optical lines, and a test light having a wavelength different from the communication light is supplied to the plurality of optical lines. An optical line test apparatus for transmitting and testing an optical line, wherein each of the optical lines is connected to one of the adjacent optical lines with respect to two of the adjacent optical lines. One end on the device side is coupled, and the other end on the second optical transmission device side is coupled to the other adjacent optical line, and between the one optical line and the other optical line. A plurality of multiplexing / demultiplexing means for branching and transmitting only the test light and the reflected light thereof, coupled to a first optical line of the plurality of optical lines, and the test light and its Testing means for branching only the reflected light to test each of the optical paths; An optical path test provided at a required portion of an optical path including a path and the multiplexing / demultiplexing means and amplifying at least the test light to be transmitted. apparatus. 3. The amplifying means provided on the optical line has a bypass for preventing reflected light traveling in a direction opposite to the traveling direction of the test light from passing through an amplification path. The optical line test device according to claim 2. 4. The test means is connected to the first optical line in the first optical transmission device, and the multiplexing / demultiplexing means coupled to one end of each optical line is connected to the first optical transmission device. The optical line test according to claim 1, wherein the multiplexing / demultiplexing means coupled to the other end of each optical line is provided within the second optical transmission device. apparatus. 5. A plurality of optical lines for coupling the first and second optical transmission devices, wherein a plurality of groups are provided in accordance with a dynamic range of a test involving an optical path length including the optical lines and the multiplexing / demultiplexing means. And the test means has a switch for selectively switching a set of optical paths to be tested and passing the test light and the reflected light only between the switched set. The optical line test apparatus according to claim 4, wherein: 6. The test means according to a first and a second path coupled to the first and last optical lines of the plurality of optical lines and a traveling direction when guiding the test light. 5. The light beam according to claim 4, further comprising a switch for selectively switching one of the first and second paths and passing the test light and the reflected light through the switched path. Road test equipment. 7. A plurality of optical transmission devices for transmitting and receiving communication light are connected by a plurality of optical lines, and test light having a wavelength different from that of the communication light is transmitted to the plurality of optical lines. In an optical line test device that performs a test of an optical line, a test communication control device for performing a test and communication is connected to each end of each of the plurality of optical lines, and each of the test communication control devices includes: A plurality of multiplexing / demultiplexing means connected to an optical line and branching and transmitting only light having the same wavelength as the test light between the optical lines, and communication light having the same wavelength as the test light; And a test communication unit for performing test communication with a partner test communication control device through each of the multiplexing / demultiplexing units and the connected optical lines. 8. The test communication means inserts a predetermined pattern when transmitting the communication light when it is on the transmission side, and when the communication light is received when it is on the reception side. A bit error rate is measured based on the inserted predetermined pattern, and each of the test communication control devices determines whether the optical line is normal or abnormal according to the measured bit error rate, and determines that the optical line is abnormal. The optical line test apparatus according to claim 7, wherein the optical line test is controlled when a result is obtained. 9. Each of the test communication control devices has an external interface unit that manages an interface with a higher-level device, and when the normal / abnormal judgment results in an abnormality, the external interface unit The optical line test apparatus according to claim 8, wherein an abnormality is notified to the higher-level device via the interface.