JPH08111665A - Optical communication network monitoring method and monitoring system - Google Patents

Abstract

PURPOSE: To obtain the monitoring method and the monitoring system of an optical communication network capable of securing highly reliable and efficient monitoring by performing a centralized monitoring about the presence or absence of the abnormality of an optical fiber line and directly searching an abnormality generation part. CONSTITUTION: Inspection light hν is made incident from a light projecting part 7 to trunk optical fiber lines 3a to 3c, the light is reflected by the reflection parts R1 to RN provided on one side of branch line fiber lines W1 to WN connected to passive branching elements 5a to 5c, and the returned reflected light Rν is measured by a light receiving part 8. Reflection wavelengths λ1 to λN of respective reflection parts are made to correspond to the branch line fiber lines W1 to WN by 1 to 1 relation. When a control part 10 detects an unreturned relected light component, the effect that an abnormlity exists in the branch line fiber line provided with the reflection part corresponding to the undetected reflected light component is discriminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring method and a monitoring system for monitoring the state of an optical fiber line in an optical communication network.

[0002]

2. Description of the Related Art In recent years, as is known in subscriber optical communication networks and CATV networks, passive branching elements (for example, star couplers) are connected to a basic optical fiber line extending from a transmitting station, and the passive branching elements are connected. Through this, a dendritic network configuration in which a plurality of subscribers are connected through a plurality of optical fiber lines (that is, branch fiber lines) has come to be studied, and such a dendritic optical communication having such a wide area. Optical communication services are being provided to a large number of subscribers over the network with excellent economic efficiency.

Here, in an optical communication network having such a dendritic network structure, the number of branch fiber lines connected to the branch downstream side (subscriber side) of the passive branch element becomes enormous. , It is necessary to efficiently search for the presence or absence of abnormality in these branch fiber lines. Particularly in an optical communication network that is becoming more and more complicated in the future, it is desirable to perform intensive monitoring at a transmitting station in order to secure high transmission quality and maintain high transmission efficiency.

Conventionally, for such a technical problem, a failure position searching method disclosed in Japanese Patent Laid-Open No. 4-340435 is known. This is because the reflection waveform (waveform by calculation) obtained when the optical pulse data for search is applied to the calculation model of the optical communication network is simulated beforehand, and the optical fiber line of the optical communication network is actually searched. The presence / absence of abnormality is estimated from the above-mentioned calculation model by comparing the reflected waveform measured when the optical pulse for transmission is transmitted with the waveform obtained by the simulation.

[0005]

However, in such a conventional fault location searching method, it is fast and fast to create a calculation model suitable for an actual optical communication network and perform the simulation as described above. It is necessary to introduce a large-scale computer, etc., and it is extremely difficult to cope with an increasingly complicated optical communication network. Furthermore, since the abnormal part is analyzed and estimated based on the calculation model, there is a problem such as a decrease in reliability due to an analysis error.

The present invention has been made in view of the problems of the prior art as described above, and promptly and centrally monitors the presence or absence of an abnormality in the optical communication network without causing a decrease in the optical communication efficiency under normal conditions. It is an object of the present invention to provide a monitoring method and a monitoring system for an optical communication network, which can realize high-precision and highly-efficient monitoring even for a complicated optical communication network.

[0007]

In order to achieve such an object, the present invention first provides an optical communication network in which a plurality of branch fiber lines are connected to a passive branch element in a dendritic manner. The present invention is directed to an optical communication network monitoring method and a monitoring system for monitoring a dendritic optical communication network in which one stage or two or more stages are cascade-connected to a fiber line.

As a first embodiment, a reflection wavelength for reflecting light having a specific wavelength determined in correspondence with each branch fiber line is set on one side of each branch fiber line. An inspection light having a wavelength equal to one of the reflection wavelengths set in the reflection portion is provided with a reflection portion,
Alternatively, the inspection light having a wide wavelength including all the reflection wavelengths set in the reflection part is made incident on the main optical fiber line from the light projecting part, and is reflected by the reflection part and returned to the main optical fiber line. Measures the light intensity or the amount of received light for each wavelength of the reflected light that comes in, and the measured value of the light intensity or the amount of received light among the wavelengths that match the wavelength of the inspection light and the reflection wavelength set in the reflecting section. Analyzes the presence or absence of wavelength components that do not satisfy the predetermined reference value, and determines that an abnormality has occurred in the branch fiber line provided with a reflection portion having a reflection wavelength equal to the wavelength component that does not meet the reference value. did.

As a second embodiment, an optical communication network in which a plurality of branch fiber lines are connected to a passive branch element in a dendrite form is provided in one or two or more stages with respect to the upstream main optical fiber line. For an optical communication network monitoring method and a monitoring system for monitoring a dendritic optical communication network that is cascade-connected, one side of each branch fiber line and one side of a different separation distance from the passive branch element. A pulsed inspection light having a wavelength equal to the reflection wavelength set in the reflection portion, or a reflection portion set in the reflection portion A pulsed inspection light having a wide wavelength including a wavelength is made incident on the trunk optical fiber line from a light projecting unit, and is reflected by the reflection unit in the form of a pulsed light train returning to the trunk optical fiber line. Measure When there is unmeasured pulsed light at each predetermined propagation delay time from the incident time of the inspection light to the measurement time of each pulsed light, a reflector corresponding to the unmeasured pulsed light is provided. It was decided to determine that an abnormality had occurred in the branch fiber line.

As a third embodiment, an optical communication network in which a plurality of branch fiber lines are connected to the passive branch element in a dendrite form is provided in one or more stages with respect to the upstream main optical fiber line. For an optical communication network monitoring method and a monitoring system for monitoring a dendritic optical communication network that is cascade-connected, one side of each branch fiber line and one side of a different separation distance from the passive branch element. , An inspection of a wavelength equal to any one of the reflection wavelengths set in the reflection section is provided by providing a reflection section in which a reflection wavelength for reflecting light of a specific wavelength determined in association with each branch fiber line is set. Light or inspection light having a wide wavelength including all reflection wavelengths set in the reflection part is made incident on the main line optical fiber line from a light projecting part, and is reflected by the reflection part to be the main line optical fiber line. The reflected light in the form of a pulsed light train returning to is measured, and among the wavelengths matching the wavelength of the inspection light and the reflection wavelength set in the reflection section, the predetermined light intensity or the received light amount is not satisfied. While analyzing the wavelength of the pulsed light in the reflected light, detecting the pulsed light not measured at each propagation delay time predetermined from the incident time of the inspection light to the measurement time of each pulsed light, the predetermined A branch line provided with a reflection part having a reflection wavelength equal to the wavelength of the pulsed light in the reflected light that does not satisfy the light intensity or the amount of received light, or a branch line provided with a reflection part corresponding to the unmeasured pulsed light. It was decided to determine that an abnormality had occurred in the fiber line.

As a fourth embodiment, an optical communication network in which a plurality of branch fiber lines are connected to the passive branch element in a dendritic manner is provided in one or two or more stages with respect to the upstream main optical fiber line. An optical communication network monitoring method and a monitoring system for monitoring a dendritic optical communication network that is cascade-connected, wherein an optical communication network in which a plurality of branch fiber lines are connected in a dendritic manner to a passive branch element is an upstream trunk line. An optical communication network monitoring method for monitoring a dendritic optical communication network in which one stage or two or more stages are cascade-connected to an optical fiber line, wherein the passive branch element is one side of each branch fiber line On one side of each of the different separation distances from each other, a reflecting portion in which a reflection wavelength for reflecting light of a specific wavelength determined in association with each branch fiber line is set is provided, and any one of the reflecting portions is set. Or The inspection light having a wavelength equal to the emission wavelength or the inspection light having a wide wavelength including all the reflection wavelengths set in the reflection part is made incident on the main optical fiber line from the light projecting part and reflected by the reflection part. The reflected light in the form of a pulsed light train that is returned to the main optical fiber line is measured, and the measurement result of each of the pulsed lights is determined in advance from the time of incidence of the inspection light to the time of measurement of each of the pulsed lights. Each propagation delay time or each separation distance, and the wavelength of each pulsed light is subjected to an array process to a data group of a matrix array, and the data group of the matrix array and data of a predetermined matrix array. Data that do not match each other is detected by comparing the groups, and on the branch fiber line corresponding to the data that does not match each other,
It was decided to determine that an abnormality had occurred.

[0012]

According to the first embodiment of the present invention, when the predetermined inspection light is incident on the upstream main optical fiber line, the downstream side is passed through the passive branching element as in normal optical communication. It is transmitted to the branch fiber line. The inspection light is reflected by the reflection portion provided on the branch fiber line, becomes reflected light, and returns in reverse through the optical path. Then, this reflected light is a set of wavelength light that is wavelength-divided by the reflection wavelength set in each reflecting portion. Furthermore,
Since each reflecting portion and branch fiber line are associated with each other on a one-to-one basis based on their inherent wavelength selectivity, the reflected light intensity and the amount of received light obtained by receiving light at each wavelength for a predetermined time can be calculated. It is possible to directly determine an abnormal branch fiber line by measuring and comparing with the condition measured in advance at the normal time. That is, if all branch fiber lines are normal, all wavelength light (reflected light) corresponding to the number of all branch fiber lines will be measured, so it can be determined that there is no abnormality, If there is an abnormality such as disconnection in the line, the wavelength component corresponding to that branch fiber line will be missing from the reflected light.Therefore, from the missing wavelength component, the abnormal branch fiber line can be directly detected. Can be determined. In addition, when there are abnormalities in a plurality of branch fiber lines at the same time, a plurality of wavelength components corresponding to these branch fiber lines are missing, so that it is possible to directly determine the abnormality of the plurality of branch fiber lines. it can.

According to the second embodiment of the present invention, when the pulsed inspection light is incident on the optical fiber line on the upstream side, the downstream side is passed through the passive branching element as in normal optical communication. It is transmitted to the branch fiber line. On the other hand, since the reflectors provided on the respective branch line fiber lines are arranged at mutually different specific separation distances from the passive branch elements that are commonly branched and connected, each branch line fiber line is It is specified based on the intrinsic separation distance from the branching element. Therefore, the propagation delay time when each inspection light is reflected by each reflection portion and returns in the opposite direction is different for each branch fiber line. Therefore, if all branch fiber lines are normal, the reflected light will be measured at each propagation delay time, so it can be judged as normal based on the light intensity or the amount of received light, while on the other hand, due to disconnection, etc. If there is an abnormal branch fiber line due to this, the reflected light component specific to that abnormal branch fiber line will not return, so the abnormal branch fiber line is directly determined based on the light intensity or the amount of received light of the reflected light. be able to.

According to the third embodiment of the present invention, both functions described in the first and second embodiments are exhibited. That is, the branch fiber line is specified by the difference in the propagation delay time corresponding to the reflection wavelength of the reflection part and the separation distance. By measuring each branch, it is possible to identify the presence / absence of abnormality in all branch fiber lines and to identify the location of abnormality.

According to the fourth embodiment of the present invention, the reflected light with respect to the predetermined inspection light is measured for each reflection wavelength and propagation delay time of each reflection portion, and these measurement results are used as the characteristic parameters. Since the array processing is performed on the data group of the matrix array, it is suitable for computer processing and the like.

[0016]

【Example】

<First Embodiment> A first embodiment of the present invention will be described with reference to the drawings. First, the basic configuration of an optical communication network to which the monitoring system of this embodiment is applied will be described with reference to FIG. One or more trunk optical fiber lines extended from a transmission device 2 installed in a station 1 such as a CATV system or subscriber communication network (in the figure, three trunk optical fiber lines are representatively shown. shows a _{3 a, 3 b, 3 c} ) are bundled as an optical fiber cable 4 is laid to a downstream subscriber, further connected to one end of the trunk optical fiber line 3 _a, 3 _b, 3 _c passive splitter 5 _a, 5 _b, 5 via a _c plurality of branch fiber line is connected to a dendritic, it is connected subscriber terminal unit to the end of the branch fiber line each.

Next, the structure of the monitoring system will be described.
Since each branch fiber line group branched and connected to the passive branch elements 5 _a , 5 _b , and 5 _c is monitored based on the same principle, the terminal devices CM _{1 to} CM _N in the figure are not monitored. The abnormality monitoring of the connected branch fiber lines W _{1 to} W _N will be described as a representative. Further, also in the description of the second and subsequent embodiments, a branch fiber line network subordinately connected to the passive branching element 5b in a dendritic manner will be described.

In FIG. 1, this monitoring system is preliminarily provided in the middle of the monitoring device 6 and the trunk coupler 7 installed in the station building 1 and the branch fiber lines W _{1 to} W _N to be monitored. It is constituted by the reflective portion R ₁ to R _N.

The monitoring device 6 includes a light projecting portion 8 for emitting inspection light (also called probe light) hν for abnormality inspection, and a reflecting portion R.
₁ to R _N reflected light coming reflected by (details will be described later) and the light receiving unit 8 for converting to a signal processable data receiving Arunyu, to control these light projecting portion 8 and the light receiving portion 9 A bidirectional optical coupler 11 and a control unit 10 for monitoring abnormality based on the data output from the light receiving unit 9 are also provided.

The trunk line coupler 7 has an optical branching device 12 and bidirectional optical couplers 13 _a , 13 _b , 13 _c provided at one end of the trunk optical fiber lines 3 _a , 3 _b , 3 _c. Then, the optical branching device 12 optically switches and connects any one of the bidirectional optical couplers 13 _a , 13 _b , and 13 _c and the bidirectional optical coupler 11 in the monitoring device 6. That is, when monitoring the abnormality of the branch fiber lines W _{1 to} W _N connected to the passive branching element 5 _b , the optical branching device 12 optically connects the bidirectional optical coupler 11 and the bidirectional optical coupler 13 _b. By doing so, the inspection light hν from the light projecting unit 8 is transmitted to the branch line fiber lines W _{1 to} W _N via the main optical fiber line 3 _b or the passive branching element 5 _b, and the inspection light hν is further transmitted. transmitting the reflected light Rν which is reflected by the R ₁ to R _N returning the branch line fiber line W ₁ to _W-N reversed to bidirectional optical coupler 11.

As described above, the bidirectional optical coupler 11 transmits the inspection light hν emitted from the light projecting portion 8 to the optical branching device 12 and the reflected light Rν from the optical branching device 12 in the light receiving portion 9.
It has a bidirectionality of transmitting to.

The reflected portion R ₁ to R _N, as shown collectively for each branch fiber line in FIG. 2 (a), is transmitted to the branch line fiber line W ₁ to _W-N via a passive splitter 5 _b Of the incoming inspection light hν, only the light having a preset specific wavelength is selectively reflected, but the communication signal light transmitted by the transmission device 2 is a light having wavelength selectivity that allows the communication signal light to pass through the terminals CM _{1 to} CM _N as it is. a reflective filter, pre-reflective portion R ₁ to R reflection wavelengths different from each other every _N lambda ₁ to [lambda] _N
Is set to In other words, the reflection wavelength lambda ₁ of the reflective portion R _1, the reflection wavelength of the reflection portion R ₂ is lambda _2, and so on to the reflection wavelength of the reflected portion R _N is set to lambda _N, and these reflection wavelength lambda ₁ ~ λ _N are mutually exclusive.

[0023] Also, these reflective portion R ₁ to R _N, may be applied an optical filter having a known reflection wavelength selectivity, but the reflective portion R ₁ to R _N of this embodiment, FIG. 3 As shown in (a), in the core of each branch fiber line W _{1 to} W _N , a plurality of media F having a refractive index different from that of the core are integrally formed in a striped pattern, so that the wavelength selectivity is exhibited. ing. Then, as shown in fragmentary cross-sectional view of FIG. 3 (b) (c), by varying for each reflective portion R ₁ to R _N the number of plurality of medium F provided at predetermined intervals d, the following According to the relational expression (1), different reflection wavelengths λ are set. λ = 2nd (1) (where, n is the average refractive index of the reflecting portion, d is the distance between the mediums F) Incidentally, the detailed structure of the reflecting portion is described in JP-A-5-3071.
No. 19 publication. In addition, the reflecting portion R having another configuration
₁ as to R _N, by setting the reflection wavelength of the respective portions plurality, so as to perform identification of and while abnormal monitor each branch line fiber line W ₁ to _W-N in each specific plurality of reflection wavelengths Good. That is, the reflective portion R ₁ to R _N shown in FIG. 3 (a) ~ (c) are respectively specific single reflection wavelength lambda ₁ ~
Although it is set to λ _N , in contrast to this, for example, in FIG.
As shown in (d), the reflection wavelength band of the reflection part R ₁ is set to WR.
₁ , the plurality of (for example, m) reflection wavelengths λ ₁₁ , λ _{12 to} λ _1m included in the reflection wavelength band WR ₁ are set to the plurality of light reflection filters r ₁₁ , r _{12 to} r _1m as cores. arranged in series in the same manner for other reflective portion R ₂ to R _N, a predetermined wavelength band allocated to each exclusive independent relationship WR ₂
A light reflection filter of each plurality are formed in each branch fiber line W ₂ to _W-N for each to WR _N. Thus, setting a plurality of reflection wavelength and bandwidth divided into the reflective portion R ₁ to R _N, by associating each wavelength into a digital bit data, each branch fiber line W ₁ to _W-N m-bit It can be identified as code data, etc., and the control unit 1
It is possible to improve the efficiency of the processing capacity for the abnormality monitoring processing by the microcomputer system or the like built in the 0.

[0024] Furthermore, as the reflection portion R ₁ to R _N of another configuration, as shown in FIG. 2 (b), the branch fiber line W ₁ ~
A passive branching device having a bi-directional in each of W _N may be provided to through these passive branching device provided with a respective reflecting portions R ₁ to R _N. According to the configuration of FIG. 2 (b),
The communication signal light transmitted from the transmission apparatus 2 within the true optical transmission path for transmitting to the terminal device CM ₁ ~CM _N through the branch line fiber line W ₁ to _W-N, reflective portion R ₁ to R _N Since it does not directly intervene, the reflection portion R ₁ for the communication signal light
There is an advantage that it is possible to prevent the influence of the to R _N. Furthermore, it can be used not only to the light reflection filter shown, for example, various types of reflective wavelength filters, such as the well-known reflection wavelength filter in the reflective portion R ₁ to R _N FIG 3 (a) ~ (c) Therefore, it is possible to obtain an effect such that the degree of freedom in design is improved.

Further, as shown in FIG. 2C, a plurality of bidirectional passive branching elements (for example, two in the figure) are provided on each of the branch fiber lines W _{1 to} W _N. A plurality of reflectors may be connected to these passive branch elements. Then, the respective reflection wavelengths of the plurality of reflecting portions are band-divided into the wavelength bands WR _{1 to} WR _N unique to each branch fiber line W _{1 to} W _N , and are determined in advance. According to such a configuration, the reflection portion R ₁ for the communication signal light
Effect it is possible to prevent the to R _N, 3
Effect described above in (d) i.e., the reflection portion R ₁ to R _N
By associating the respective wavelengths set in the above with the digital bit data, the respective branch fiber lines W _{1 to} W _N can be identified by the code data or the like. Moreover, effects such that the degree of freedom in design is improved can be obtained since it is possible to use various types of reflective portion R ₁ to R _N.

However, FIGS. 2 (a) to 2 (c) and FIG. 3 (d)
In any case shown, these reflective portion R ₁ ~
R _N is provided only the communication signal light as close as possible to the upstream side of the normal band-limiting filter having a transmission wavelength selectivity is provided for passing to the terminal device CM ₁ ~CM _N. That is, it is provided so that the monitoring range of each branch fiber line W _{1 to} W _N to be monitored is as wide as possible.

Next, referring to FIGS. 4 and 5, the monitoring device 6
Will be described in detail.

Firstly, the light projecting unit 8, as shown in FIG. 4, includes a light source 8 _a and the wavelength tunable filter 8 _b, the light source 8 _a is 5
(A) all as shown in reflective portion R ₁ to R reflection wavelength is set to _N lambda ₁ to [lambda] _N encompassing light (e.g., white light) was continuously emitted, tunable filter 8 _b is a light source 8 light emitted from _a is incident, the permselective wavelength, for example, continuously sweep changes from the short wavelength lambda _L to (a relation of _{λ L ≦ λ 1 ~λ N ≦} λ H) long wavelength lambda _H As a result, the inspection light hν whose wavelength continuously changes is supplied to the bidirectional optical coupler 11
Transmit to. Further, the drive circuit 10 _a in the control unit 10 _keeps the emission intensity of the light source 8 _a constant, and the wavelength setting circuit 10 _b controls the transmission selection wavelength of the wavelength tunable filter 8 _b .

As a result, the inspection light hν is reflected by the reflecting portions R _{1 to} R with the passage of time as shown in the relationship of FIG.
Becomes light of a wavelength corresponding to _N, is transmitted to the branch fiber line W ₁ to _W-N via a bidirectional optical coupler 11 and the optical splitter 12 and the two-way optical coupler 13 _b, reflection portion R ₁ to R _N are each The inspection light hν having a specific wavelength is reflected. Then, these reflected lights become reflected light Rν, go backward in the main optical fiber line 3 _b , and again the bidirectional optical coupler 13 _b.
Then, the light enters the light receiving section 9 through the optical branching device 12 and the bidirectional optical coupler 11 _b .

As shown in FIG. 4, the light receiving section 9 receives the reflected light R
a photoelectric conversion element 9 _a for photoelectrically converting [nu, photoelectric conversion elements 9
_The photoelectric conversion signal output from a is converted to digital data by A /
An A / D converter 9 _b that performs D conversion and supplies to the control unit 10 is provided.

[0031] Therefore, in a case where FIGS. 2 (a) or FIG. 2 (b) each specific single wavelength lambda ₁ to [lambda] reflecting section is set to _N R ₁ to R _N shown in is used , If all branch fiber lines W _{1 to} W _N are normal,
As shown in (c), the reflected light Rν is reflected by all the reflection parts R ₁
Will have a time divided reflected light component of the wavelength lambda ₁ to [lambda] _N corresponding to to R _N, the A / D converter 9 _a,
Digital data representing the light intensity (or the amount of received light) for each wavelength λ _{1 to} λ _N is output.

On the other hand, in a case where the reflective portion R ₁ to R _N, which is set to each specific single wavelength lambda ₁ to [lambda] _N are used, either the branch fiber lines, for example, branch line fiber line W ₂ If an error such as disconnection occurs during the
As shown in FIG. 5D, the wavelength λ corresponding to the reflection part R _2
Since the reflected light component of ₂ is missing from the reflected light Rν, A / D
Of the digital data output from the converter 9 _a, the value of the digital data representing the light intensity (or the amount of received light) for this wavelength λ ₂ is smaller than that in the normal case. Even if an abnormality occurs in two or more branch fiber lines, the corresponding two or more wavelength components are similarly missing from the reflected light Rν, and A / D
Of the digital data output from the transducer 9 _a, the value of the digital data of the missing wavelength components is smaller than the normal.

Further, as shown in FIG. 2 (c) or FIG. 3 (d), a case where a plurality of reflecting portions having a plurality of reflection wavelengths are provided for each of the branch fiber lines W _{1 to} W _N , and all branch lines are provided. if there is no abnormality in the fiber line W ₁ to _W-N, as shown in FIG. 5 (e), the reflected light Rν a wavelength lambda ₁₁ to [lambda] _{1 m} of each plurality corresponding to the reflective portion R ₁ to R _N, λ _{21 to} λ _2m , ……, λ _{N1 to} λ
_Since it has a reflected light component of _Nm , the A / D converter 9b
Will output digital data representing these light intensities (or received light amounts).

On the other hand, when a plurality of reflection wavelength reflecting portions are provided for each of the branch line fiber lines W _{1 to} W _N, an abnormality such as a disconnection occurs in the middle of any of the branch line fiber lines, for example, the branch line fiber line W _2. 5F, the reflected light components of the group of reflected wavelengths λ _{21 to} λ _2m set in the reflecting portion R ₂ are missing from the reflected light Rν, as shown in FIG.
Of the digital data output from the / D converter 9 _b ,
The value of the digital data representing the light intensity (or the amount of received light) of the group of wavelengths λ _{21 to} λ _2m becomes smaller than that in the normal case.
Similarly, even if an abnormality occurs in two or more branch fiber lines, the light of the corresponding reflected wavelength components of two or more groups is reflected light Rν.
The digital data of the missing wavelength component in the digital data output from the A / D converter 9 _b is smaller than that in the normal case.

[0035] Thus, digital data for each wavelength output from the A / D converter 9 _b, since associated with the reflection wavelength of each of the reflective portion R ₁ to R _N, a branch fiber line It has the information on the presence / absence of an abnormality and the information for identifying the branch fiber line in which the abnormality has occurred.

The control unit 10 compares the digital data for each wavelength with predetermined determination reference data to determine whether there is an abnormality and to determine the branch fiber line in which the abnormality has occurred. For example, a predetermined threshold value is set as a predetermined determination criterion, and the branch fiber line in which the abnormality has occurred is identified and determined based on the reflection wavelength of the digital data that is less than or equal to this threshold value. Further, a warning such as displaying information about a branch fiber line in which an abnormality has occurred on a display or sounding an alarm device is given.

As described above, according to this embodiment, it is only necessary to detect the light intensity (or the amount of received light) of the reflected light Rν with respect to the inspection light hν for each predetermined wavelength, and it is possible to determine whether or not there is an abnormality in the branch fiber line and which branch line. Since it is possible to centrally monitor whether or not an abnormality has occurred in the fiber line on the side of the station building 1, it is possible to easily maintain and manage the optical communication network, and it is possible to promptly deal with the occurrence of the abnormality. Further, it is possible to perform highly accurate monitoring with a relatively simple system configuration, and further, a monitoring system having expandability capable of easily supporting a complicated optical communication network and an optical communication network that is gradually expanded. Can be provided.

[0038] In this embodiment, allowed to continuously emit light of a wide wavelength range from the light source 8 _a, the inspection light hν by continuously varying the selection wavelength of the tunable filter 8 _b
5 (g) or 5 (h) by controlling the wavelength tunable filter _8b at a predetermined timing instead of continuously changing it in this manner.
As shown in, it may be caused to emit discretely generated thereby with inspection light hν in a time-division wavelength light component corresponding to a reflection wavelength which is set in the reflective portion R ₁ to R _N. By the way,
FIG. 5 (g) shows the reflecting portions R ₁ to R ₁ set to the unique single reflection wavelengths λ _{1 to} λ _N shown in FIG. 2 (a) or FIG. 2 (b), respectively.
Shows the inspection light hv in the case of applying the R _N, reflected light Rν as shown in FIG. 5 (c) or FIG. 5 (d) will be detected against such inspection light hv. On the other hand, FIG.
, As shown in FIG. 2 (c) or FIG. 3 (d), the reflection portion reflecting wavelengths respectively by a plurality is set R ₁ to R _N
Shows the inspection light hν in the case of applying
In contrast, the reflected light Rν as shown in FIG. 5 (e) or FIG. 5 (f) will be detected. Therefore, even with the inspection light hν in which each wavelength component is generated in this time division,
Centralized and quick abnormality monitoring can be performed.

<Embodiment 2> Next, a second embodiment will be described with reference to FIG. 6 shows the configuration of the monitoring device installed in the station building, and the same or corresponding parts as in FIG. 4 are denoted by the same reference numerals.

Firstly, a schematic configuration of a monitoring system in this embodiment is similar to FIG. 1, further, the branch fiber line W ₁ to W-reflection portion is provided in association with the _N R ₁ to R _N
2 may be any of those shown in FIGS.

This embodiment will be described in comparison with the first embodiment. In FIG. 6, the light receiving portion is provided with a spectrum analyzer 14 for receiving the reflected light Rν from the bidirectional optical coupler 11 and performing spectrum analysis. The control unit 10 is provided and inputs the spectrum distribution data output from the spectrum analyzer 14 to determine whether or not there is an abnormality in the branch fiber lines W _{1 to} W _N to be monitored and to determine the abnormal location.

That is, as shown in FIGS. 5 (a) and 5 (b),
The inspection light hν whose wavelength is continuously changed by the light source 8 _a and the wavelength tunable filter 8 _b is supplied to the branch fiber lines W _{1 to} W _N via the bidirectional optical coupler 11, the optical branching device 12, and the bidirectional optical coupler 13 _b. When transmitted to, only the light having the reflection wavelength set in the reflective portion R ₁ to R _N is reflected, the reflected light Rν
Then, the light again enters the spectrum analyzer 14 via the bidirectional optical coupler 11. Spectrum analyzer 1
4, since the spectral analysis of the broad wavelength band including all wavelength components of the reflected light Arunyu, the data of the spectrum distribution of the reflected wave of each set in the reflective portion R ₁ to R _N to the control unit 10 outputs To do.

All branch fiber lines W _{1 to} W
If there is no abnormality in _N , the spectrum distribution data of all the reflection wavelengths as shown in FIG. 5 (c) or FIG. 5 (e) is generated, while the abnormality is generated in any branch fiber line. For example, as shown in FIG. 5D or FIG. 5F, the value of the spectrum data of the reflection wavelength peculiar to the reflection part attached to the branch fiber line becomes smaller than the normal condition.

Therefore, in the second embodiment, the microcomputer system or the like in the control unit 10 compares the spectrum distribution data from the spectrum analyzer 14 with predetermined reference data,
Whether or not there is an abnormality in the branch fiber line and which branch fiber line has an abnormality are centrally monitored, and prompt measures can be taken against the occurrence of the abnormality. Further, it is possible to perform highly accurate monitoring with a relatively simple system configuration, and further, it has the expandability to easily cope with a complicated optical communication network and an optical communication network that is gradually expanded. .

In this embodiment, the inspection light hν is
Depending on the type of the reflective portion R ₁ to R _N to be used, Figure 5
Either the continuous emission shown in (b) or the discrete emission by time division shown in (g) or (h) of the figure may be applied. By the way, the inspection light h by the above continuous emission
5 (c) or (d) or FIG. 5 (e) for ν
Alternatively, the reflected light Rν as shown in (f) is detected, and the reflected light Rν as shown in FIG. 5 (e) or (f) is detected with respect to the inspection light hν by the discrete emission. Therefore, in any case, centralized monitoring can be performed.

<Embodiment 3> Next, a third embodiment will be described with reference to FIG. Note that FIG. 7 shows the configuration of the monitoring device installed in the station building, and the same or corresponding parts as in FIG. 4 are denoted by the same reference numerals.

Firstly, a schematic configuration of a monitoring system in this embodiment is similar to FIG. 1, further, the reflective portion R ₁ to R _N provided in association with each branch fiber line W ₁ to _W-N
2 may be any of those shown in FIGS.

The structure of the monitoring device 6 of this embodiment will be described in comparison with the monitoring device shown in FIG. 4. In FIG. 7, the light receiving section photoelectrically converts the reflected light Rν from the bidirectional optical coupler 11. A conversion element 9 _a and A for converting the photoelectric conversion signal output from the photoelectric conversion element 9 _a into digital data
A / D converter _9b is provided. The light projecting unit includes a variable wavelength light source 15 such as a variable wavelength laser, and the wavelength setting circuit 16 controls the emission wavelength of the variable wavelength light source 15 in response to a command from the control unit 10, whereby the reflecting units R _{1 to} R _N. The inspection light hν having a wavelength component corresponding to the reflection wavelength set to 1 is emitted to the bidirectional optical coupler 11.

[0049] Then, to the monitoring systems using FIGS. 2 (a) or reflected portion single reflection wavelength lambda ₁ to [lambda] _N are set respectively as shown in (b) R ₁ ~R _N is , The wavelength component of the inspection light hν is continuously changed as shown in FIGS. 5A and 5B, or is discretely changed in a time division manner as shown in FIG. 5G. The wavelength variable light source 15 is driven and controlled. As a result, the reflected light Rν has a spectrum as shown in FIG. 5C or 5D depending on the presence or absence of abnormality, and the digital data of the light intensity (or the amount of received light) for each wavelength is A / D converted. It is output from the device 9 _b .

On the other hand, as shown in FIG. 2 (c) or FIG. 3 (d), the relative surveillance system employing reflective portion R ₁ to R _N reflection wavelength of the respective portions plurality is set The wavelength tunable light source 15 is arranged so as to change the wavelength component of the inspection light hν continuously as shown in FIG. 5B or discretely as time division as shown in FIG. 5H. Drive control. As a result, the reflected light Rν has a spectrum as shown in FIG. 5E or 5F depending on the presence or absence of abnormality, and the digital data of the light intensity (or the amount of received light) for each wavelength is A / D converted. It is output from the device 9 _b .

Therefore, it is possible to perform intensive and rapid abnormality monitoring also by the inspection light hν in which each wavelength component is generated in a time division manner.

<Fourth Embodiment> Next, a fourth embodiment will be described with reference to FIG. Note that FIG. 8 shows the configuration of the monitoring device installed in the station building, and the same or corresponding portions as those in FIGS. 6 and 7 are denoted by the same reference numerals.

Firstly, a schematic configuration of a monitoring system in this embodiment is similar to FIG. 1, further, the branch fiber line W ₁ to W-reflection portion is provided in association with the _N R ₁ to R _N
2 may be any of those shown in FIGS.

The structure of the monitoring apparatus 6 of this embodiment will be described in comparison with the monitoring apparatus shown in FIGS. 6 and 7. In FIG. 8, the light receiving section has a reflected light Rν from the bidirectional optical coupler 11. A spectrum analyzer 14 for receiving the light and performing a spectral analysis is provided, and the control unit 10 inputs the data of the spectrum distribution output from the spectrum analyzer 14, whereby the branch fiber lines W _{1 to} W _N to be monitored are The presence / absence of abnormality and the process of determining the abnormal branch fiber are performed.

The light projecting section is provided with a variable wavelength light source 15 such as a variable wavelength laser, and the wavelength setting circuit 16 controls the emission wavelength of the variable wavelength light source 15 in response to a command from the control section 10, whereby the reflecting section R is provided. has an inspection light hν having a wavelength component corresponding to the reflection wavelength is set to ₁ to R _N to be emitted to the bidirectional optical coupler 11.

[0056] Then, to the monitoring system using the reflection portion R ₁ to R _N of FIGS. 2 (a) or respectively as shown in (b) 's inherent single reflection wavelength lambda ₁ to [lambda] _N is set Is
The wavelength component of the inspection light hν is changed so as to be continuously changed as shown in FIGS. 5A and 5B or to be changed discretely in a time division as shown in FIG. 5G. The variable light source 15 is drive-controlled. As a result, the reflected light Rν has a spectrum as shown in FIG. 5C or 5D depending on the presence or absence of abnormality, and the spectrum analyzer 14 outputs the spectrum distribution data for each wavelength.

Meanwhile, as shown in FIG. 2 (c) or FIG. 3 (d), the relative surveillance system for applying the reflective portion R ₁ to R _N reflection wavelength of the respective portions plurality is set The wavelength tunable light source 15 is arranged so as to change the wavelength component of the inspection light hν continuously as shown in FIG. 5B or discretely as time division as shown in FIG. 5H. Drive control. As a result, the reflected light Rν has a spectrum as shown in FIG. 5E or 5F depending on whether or not there is an abnormality, and the spectrum analyzer 14 outputs the spectrum distribution data for each wavelength.

Therefore, it is possible to perform the intensive and rapid abnormality monitoring by the inspection light hν in which each wavelength component is generated in the time division manner as described above.

<Fifth Embodiment> Next, a fifth embodiment will be described with reference to FIG. Note that FIG. 9 shows the configuration of the monitoring device 6 installed in the station building, and the same or corresponding parts as in FIG. 4 are denoted by the same reference numerals. First, a schematic configuration of a monitoring system in this embodiment is similar to FIG. 1, further, the reflective portion R ₁ ~ provided in association with each branch fiber line W ₁ to _W-N
The configuration of R _N may be any of those shown in FIGS.

The structure of the monitoring device 6 of this embodiment will be described in comparison with the monitoring device shown in FIG.
The reflected light Rν from the bidirectional optical coupler 11 is incident on the light receiving portion and is transmitted through the wavelength tunable filter 17 that continuously or discretely changes the transmission selection wavelength and the wavelength tunable filter 17 of the reflected light Rν. A photoelectric conversion element 9 _a for photoelectrically converting wavelength light, and a photoelectric conversion signal output from the photoelectric conversion element 9 _a (a signal indicating the received light amount or light intensity of the transmitted wavelength light) to digital data to control the control unit 10. Supply to A / D
A converter 9 _b are provided.

[0061] the light projecting unit, the reflection portion R ₁ to R _N wide wavelength range including the reflection wavelength is set to light (e.g., white light) source 8 _a light emitting diode or the like for emitting is provided , The drive circuit 10 _a is driven by the light source 8 in accordance with _a command from the control unit 10.
_The intensity of the emitted light of _a is controlled to be kept constant, and the wavelength setting circuit 18 variably controls the transmission selection wavelength of the wavelength tunable filter 17.

[0062] That is, in this embodiment, a predetermined light intensity and to apply the light of a predetermined broad wavelength band as the inspection light hv, is reflected in correspondence with the inspection light hv from the respective reflecting portions R ₁ to R _N The wavelength tunable filter 17 selects the wavelength of the reflected light Rν.

[0063] Then, to each as shown in FIG. 2 (a) or (b) to a monitoring system that uses the reflective portion R ₁ to R _N, which already has a unique single reflection wavelength lambda ₁ to [lambda] _N also, as shown in FIG. 2 (c) or FIG. 3 (d), the reflection portion reflecting wavelengths respectively by a plurality is set R ₁ to R _N
With respect to the monitoring system to which is applied, abnormality monitoring is realized by mutually similar operations.

[0064] First, as shown in FIG. 2 (a) or (b), in the monitoring system using the reflection portion R ₁ to R _N to each specific single reflection wavelength lambda ₁ to [lambda] _N is set The inspection light hν in the wide wavelength range is supplied to the bidirectional optical coupler 11
Or via the optical splitter 12 and the two-way optical coupler 13 _b is transmitted to the branch fiber line W ₁ to _W-N, reflective portion R ₁ ~ each being attached to each branch fiber line W ₁ to _W-N
Light having the reflection wavelength lambda ₁ to [lambda] _N of R _N is incident on the wavelength tunable filter 17 via the bidirectional optical coupler 11 again as reflected light Arunyu. Here, the inspection light hν is the first to fourth
Each wavelength component does not change in a time-division manner as in the above embodiment, but wavelength components in a wide wavelength range are simultaneously and continuously transmitted to each branch fiber line W _{1 to} W _N , so that the reflected light Rν
Similarly, the wavelength light components of the wavelengths λ ₁ to λ _N are collected at substantially the same time and continuously enter the wavelength tunable filter 17. However, since the wavelength tunable filter 17 changes the transmission selection wavelength by sweeping it, the reflected light Rν has wavelengths λ _{1 to} λ ₁ .
_It is time-divided into _N light and enters the photoelectric conversion element 9 _a . When there is no abnormality in all the branch fiber lines W _{1 to} W _N , light of each wavelength λ _{1 to} λ _N as shown in FIG. 5C is detected by time division, while the branch fiber lines W _{1 to} W _N are detected. ₁ ~
If an error occurs in any of W _N ,
As shown in (d), the lack of light of the corresponding wavelength is detected. The photoelectric conversion element 9 _a photoelectrically converts the light of each of the wavelengths λ _{1 to} λ _N , and the A / D converter 9 _b converts the light into digital data and outputs the digital data to the control unit 10. By comparing the preset reference data with the digital data from the A / D converter 9 _b , the unit 10 compares the branch fiber lines W _{1 to} W _{N with} the abnormality and the abnormality of the branch fiber. Identify and judge tracks.

[0065] Also, as shown in FIG. 2 (c) or FIG. 3 (d), the In the monitoring system for applying the reflective portion R ₁ to R _N reflection wavelength of the respective portions plurality is set first, if there is no abnormality in all branch fiber line W ₁ to _W-N is reflected light Rν, the wavelength of the plurality of groups corresponding to each reflective portion R ₁ to R _N as shown in FIG. 5 (e) On the other hand, if any of the branch fiber lines W _{1 to} W _N is abnormal, light of a group of wavelengths corresponding to the branch fiber line is missing as shown in FIG. Will be done. Then, the light of such wavelengths is converted into the photoelectric conversion element 9
_{Since a} is photoelectrically converted, and the A / D converter 9 _b is further converted into digital data and output to the control unit 10, the control unit 10
, The preset reference data and A / D converter 9 _b
By comparing with the digital data from, the presence / absence of abnormality of the branch fiber lines W _{1 to} W _N and the identification / judgment of the branch fiber line having the abnormality are performed.

As described above, according to this embodiment, whether the branch fiber lines W _{1 to} W _N to be monitored are abnormal or not,
It is possible to identify the branch fiber line where an abnormality has occurred,
Furthermore, it is possible to perform intensive and rapid abnormality monitoring on the station side.

In the above description of this embodiment,
Although the wavelength tunable filter 17 is described a case of continuously sweep the transmitted selected wavelength, the permselective wavelength corresponding to the reflection wavelength of the reflection portion R ₁ to R _N, also be discretely switched by time division Good. Be switched in this way a discrete transmissive selected wavelength, depending on the type of the reflective portion R ₁ to R _N to be used,
Figure 5 (c) or (d), or can be divided into light of each wavelength shown in FIG. 5 (e) or (f), the control unit 10 is supplied from the A / D converter 9 _b Based on the digital data, it is possible to determine whether or not there is an abnormality in the branch fiber lines W _{1 to} W _N and to identify / determine the branch fiber line in which the abnormality has occurred.

[0068] Further, intermittently flashes the light source 8 _a, in synchronism with the timing of the lighting period, the wavelength tunable filter 17
The permselective wavelengths may be changed by switching in the order corresponding to the reflection wavelength of the reflection portion R ₁ to R _N. In this way, the reflected light Rν returning to the inspection light hν emitted in each period when the light source 8 _a is turned on is changed from each reflected portion R ₁ to the reflected light Rν.
The light having the reflection wavelength that is set to to R _N, can be detected in order by the photoelectric conversion element 9 _b. That is, even in this case, in the same manner as shown in FIG. 5 (c) or (d) or FIG. (E) or (f), detecting the light for each reflection wavelength of each reflective portion R ₁ to R _N Therefore, based on the digital data supplied from the A / D converter 9 _b , the control unit 10 can determine the presence / absence of abnormality in the branch fiber lines W _{1 to} W _N and identify the branch fiber line in which the abnormality has occurred. It can be carried out.

<Embodiment 6> Next, a sixth embodiment will be described with reference to FIG.
Will be explained together. 10 shows the configuration of the monitoring device installed in the station building, and the same or corresponding parts as in FIG. 9 are denoted by the same reference numerals. Also, a schematic configuration of a monitoring system in this embodiment is similar to FIG. 1, further, the reflective portion R ₁ ~ provided in association with each branch fiber line W ₁ to _W-N
The configuration of R _N may be any of those shown in FIGS.

In FIG. 10, the light receiving section is provided with a spectrum analyzer 19 for receiving the reflected light Rν from the bidirectional optical coupler 11 and performing spectrum analysis. By inputting the spectrum distribution data for each, the presence / absence of abnormality of the branch fiber lines W _{1 to} W _N to be monitored and the determination of the branch fiber line in which the abnormality has occurred are performed.

[0071] the light projecting unit, the reflection portion R ₁ to R _N wide wavelength range including the reflection wavelength is set to light (e.g., white light) source 8 _a light emitting diode or the like for emitting is provided , The drive circuit 10 _a is driven by the light source 8 according to the command from the control unit 10.
controls to retain the emission intensity of _a constant. Therefore, in this embodiment, light having a predetermined light intensity and a predetermined wide wavelength range is applied as the inspection light hν, and the reflected light R reflected from each of the reflecting portions R1 to RN corresponding to the inspection light hν.
The spectrum analyzer 19 performs spectrum analysis on ν.

[0072] Then, to each as shown in FIG. 2 (a) or (b) to a monitoring system that uses the reflective portion R ₁ to R _N, which already has a unique single reflection wavelength lambda ₁ to [lambda] _N also, as shown in FIG. 2 (c) or FIG. 3 (d), the reflection portion reflecting wavelengths respectively by a plurality is set R ₁ to R _N
Even for a monitoring system to which is applied, abnormality monitoring is realized by mutually similar operations.

[0073] First, as shown in FIG. 2 (a) or (b), with respect to monitoring system using a reflection portion R ₁ to R _N to each specific single reflection wavelength lambda ₁ to [lambda] _N is set The inspection light hν in the wide wavelength range is the bidirectional optical coupler 11
Or via the optical splitter 12 and the two-way optical coupler 13 _b is transmitted to the branch fiber line W ₁ to _W-N, reflective portion R ₁ ~ each being attached to each branch fiber line W ₁ to _W-N
Light having the reflection wavelength lambda ₁ to [lambda] _N of R _N is incident on the spectrum analyzer 19 via a bidirectional optical coupler 11 again as reflected light Arunyu.

In this inspection light hν, wavelength components in a wide wavelength range are simultaneously and continuously applied to each branch fiber line W ₁ to W ₁ .
Since it is transmitted to W _N , the reflected light Rν also has wavelengths λ ₁ ~
The light components of wavelength λ _N are collected almost simultaneously and continuously enter the spectrum analyzer 19. However, the spectrum analyzer 19 performs spectrum analysis on a wide wavelength range including wavelengths λ _{1 to} λ _N, and therefore outputs spectrum distribution data for all reflected wavelengths λ _{1 to} λ _N.

All the branch fiber lines W _{1 to} W
_When there is no abnormality in _N , the wavelength λ as shown in FIG.
It is possible to detect the light component for each _{1 to} λ _N , and on the other hand, if any of the branch fiber lines W _{1 to} W _N has an abnormality, the corresponding wavelength as shown in FIG. Can be detected. The control unit 10 uses the preset reference data and the spectrum analyzer 1
By comparing with the data of the spectrum distribution for each wavelength output from 9 above, the branch fiber line W ₁
The presence or absence of abnormality in W _N and the line-of-sight fiber line in which abnormality exists are identified.

[0076] Also, as shown in FIG. 2 (c) or FIG. 3 (d), the In the surveillance system reflection portion R ₁ to R _N reflection wavelength of the respective portions plurality is set is applied , first, if there is no abnormality in all branch fiber line W ₁ to _W-N is reflected light Rν is a plurality of groups corresponding to each reflective portion R ₁ to R _N as shown in FIG. 5 (e) When the branch fiber lines W _{1 to} W _N are abnormal, a group of spectra corresponding to the branch fiber line is lost as shown in FIG. 5F. It will be. Then, the spectrum analyzer 19 analyzes the spectrum of each wavelength, converts it into spectrum distribution data, and outputs it to the control unit 10. The control unit 10 compares the preset reference data with the spectrum distribution data. The branch fiber line W ₁
~ Whether or not there is an abnormality in W _N and the branch fiber line in which the abnormality exists are identified and determined.

As described above, according to this embodiment, whether the branch fiber lines W _{1 to} W _N to be monitored are abnormal or not,
It is possible to identify the branch fiber line where an abnormality has occurred,
Furthermore, it is possible to perform intensive and rapid abnormality monitoring on the station side.

In the above description, the case where the light source 8a is continuously lit for _a relatively long time and monitored is described. However, the light source _8a is blinked one by one and the inspection light emitted while the light is lit. hν reflected light Rν from corresponding reflective portion R ₁ to R _N, the spectrum analyzed by the spectrum analyzer 19, to further control unit 10 performs the identification processing of the branch fiber line in the presence of absence of an abnormality and the abnormal You can

<Embodiment 7> Next, a seventh embodiment will be described with reference to FIG.
Will be explained together. Note that FIG. 11 shows the configuration of the monitoring device 6 installed in the station building, and the same or corresponding parts as in FIG. 9 are denoted by the same reference numerals. Further, the schematic configuration of the monitoring system in this embodiment is the same as that of FIG. 1, and further, the reflecting portion R ₁ provided in association with each branch fiber line W _{1 to} W _N.
Configuration of to R _N may be any of those shown in FIGS.

The structure of the monitoring device 6 of this embodiment will be described in comparison with the monitoring device shown in FIG. 9. In FIG. 11, the light receiving portion has a reflected light Rν from the bidirectional optical coupler 11 in the light receiving portion.
Is incident on the Michelson interferometer 20 for interfering the reflected light Rν, a photoelectric conversion element 9 _a for photoelectrically converting the interference light interfered by the Michelson interferometer 20, and photoelectric conversion output from the photoelectric conversion element 9 _a. An A / D converter 9 _b for converting a signal into digital data, an FFT unit 21 for performing a discrete fast Fourier transform (DFT) on the digital data output from the A / D converter 9 _b, and a controller 10.
Is provided with a drive control circuit 22 for controlling the phase of the Michelson interferometer 20. Then, the control unit 10 determines the branch fiber lines W _{1 to} W _N based on the spectrum distribution data output from the FFT unit 21.
The presence / absence of abnormality and the branch fiber line in which the abnormality has occurred are identified and determined.

[0081] The light projector, of the broad wavelength band including the reflection wavelength set in the reflective portion R ₁ to R _N light (e.g., white light) of the light-emitting diodes or the like which continuously or intermittently emit light source 8 _a is provided, the drive circuit 10 _a according to the instruction of the control unit 10 is controlled to maintain the output light intensity of the light source 8 _a constant.

[0082] That is, in this embodiment, a predetermined light intensity and to apply the light of a predetermined broad wavelength band as the inspection light hv, is reflected in correspondence with the inspection light hv from the respective reflecting portions R ₁ to R _N The Michelson interferometer 20 causes the reflected light Rν to come into interference while changing the phase, and the luminance pattern of the interference light is converted into _a photoelectric conversion element 9 _a , an A / D converter 9 _b, and an FFT unit 2.
1 for digital spectrum analysis, and the control unit 10 compares the spectrum distribution data corresponding to the interference light with predetermined reference data to determine whether the branch fiber lines W _{1 to} W _N are abnormal. Existence and
Identification of which branch fiber line has an abnormality
Make a decision.

[0083] Then, with respect to the monitoring system that uses the reflective portion R1~RN that respectively as shown in FIG. 2 (a) or (b) a unique single reflection wavelength lambda ₁ to [lambda] _N are set as shown in FIG. 2 (c) or FIG. 3 (d), the reflection portion reflecting wavelengths respectively by a plurality is set R ₁ to R _N
With respect to the monitoring system to which is applied, abnormality monitoring is realized by mutually similar operations.

[0084] First, as shown in FIG. 2 (a) or (b), in the monitoring system using the reflection portion R ₁ to R _N to each specific single reflection wavelength lambda ₁ to [lambda] _N is set The inspection light hν in the wide wavelength range is supplied to the bidirectional optical coupler 11
Or via the optical splitter 12 and the two-way optical coupler 13 _b is transmitted to the branch fiber line W ₁ to _W-N, reflective portion R ₁ ~ each being attached to each branch fiber line W ₁ to _W-N
Light having the reflection wavelength lambda ₁ to [lambda] _N of R _N via a bidirectional optical coupler 11 again as reflected light Rν Michelson interferometer 20
Incident on. Here, the Michelson interferometer 20 generates unique interference light for each of the wavelengths λ _{1 to} λ _N of the reflection wavelength Rν by continuously changing the phase, and the photoelectric conversion element 9 _a causes these interference lights. Photoelectric conversion of light. And A
The / D converter 9 _b digitizes the photoelectric conversion signals of these interference lights, and the FFT unit 22 performs the discrete fast Fourier transform processing, whereby the spectrum distribution data of these interference lights is output to the control unit 10. Therefore, when all branch fiber lines W _{1 to} W _N have no abnormality, data of a spectrum distribution equivalent to that shown in FIG. 5C is obtained, and one of the branch fiber lines W _{1 to} W _N is obtained. When an abnormality occurs in, the spectrum distribution data equivalent to that shown in FIG. 5D is obtained,
The control unit 10 compares preset reference data with data of these spectrum distributions to determine whether or not the branch fiber lines W _{1 to} W _N are abnormal and to identify the abnormal branch fiber line. To do.

[0085] Also, as shown in FIG. 2 (c) or FIG. 3 (d), the In the monitoring system for applying the reflective portion R ₁ to R _N reflection wavelength of the respective portions plurality is set first, if there is no abnormality in all branch fiber line W ₁ to _W-N, the interference light reflected Rν including the wavelength light of a plurality group corresponding to each reflective portion R ₁ to R _N is the Michelson interferometer 20 Similarly, from the FFT unit 21, spectrum distribution data (Fig.
(Equivalent to the spectrum distribution shown in (e)) is output. On the other hand, when an abnormality occurs in any of the branch fiber lines W _{1 to} W _N , the spectrum distribution equivalent to that shown in FIG. The data is output. Therefore, the control unit 10 compares preset spectral data with these spectrum distribution data to identify the presence / absence of abnormality in the branch fiber lines W _{1 to} W _N and identify the branch fiber line in which the abnormality exists. I do.

As described above, according to this embodiment, the presence or absence of abnormality in the branch fiber lines W _{1 to} W _N to be monitored,
It is possible to identify the branch fiber line where an abnormality has occurred,
Furthermore, it is possible to perform intensive and rapid abnormality monitoring on the station side.

In the above description of this embodiment,
The case of using the light source 8 _a that emits the inspection light hν in a wide wavelength range such as white light continuously or intermittently has been described, but instead of the light source 8 _a , the second embodiment shown in FIG. 6 is used. by applying the driving circuit 10 _a and the wavelength setting circuit 10 _b for controlling the light source 8 _a and the wavelength tunable filter 8 _b and their is a component, the reflective portion R ₁ reflection is set to to R _N wavelength lambda ₁ The inspection light hν whose wavelength changes sequentially corresponding to ˜λ _N may be used. Further, by applying a wavelength setting circuit 16 for driving controlling the variable wavelength light current 15 of the tunable laser or the like which is a component of the third embodiment shown in FIG. 7, the reflective portion R ₁ to R _N The inspection light hν whose wavelength sequentially changes corresponding to the reflection wavelengths λ _{1 to} λ _N set to ₁ may be used.

When the light source is replaced in this way, the inspection light h
The wavelength ν changes in a time-divisional manner, and the wavelength of the reflected light Rν incident on the Michelson interferometer 20 also changes in a time-divisional manner. Therefore, the spectrum distribution data of the interference light for each wavelength is generated from the FFT unit 21 in a time division manner, and the data substantially equivalent to the spectrum distribution data is obtained, and the control unit 10 controls the spectrum. Similar abnormality monitoring is realized by determining the presence or absence of data.

<Embodiment 8> Next, an eighth embodiment will be described with reference to FIG.
Will be explained together. Note that FIG. 12 shows a configuration example of the monitoring system of this embodiment, and the same or corresponding parts as in FIG. 1 are denoted by the same reference numerals. First, the structural features of the monitoring system of this embodiment will be described in comparison with the monitoring system shown in FIG.

In the monitoring system of FIG. 1 described above,
The conditions for the attached position of the representative and said reflection portion R ₁ to R _N, not the difference in distance from the passive splitter 5 _b to the reflection portion R ₁ to R _N each question, merely of the reflective portion R ₁
~R branch fibers by attached as close as possible to the subscriber terminal CM ₁ ~CM _N the attached position of the _N lines W ₁
Not only to set up a wide monitoring range of ~W _N. That is, by detecting and analyzing the reflected light Rν with the monitoring device 6,
Performing abnormality monitoring based on the spectral information of the reflected wave that is set in each regardless attached position of the reflective portion R ₁ to R _N s.

[0091] In contrast, the monitoring system of this embodiment shown in FIG. 12 attached to the reflective portion R ₁ to R _N from the passive splitter 5 _b at a distance L ₁ ~L _N differently to each one another , by detecting and analyzing the reflected light Rν the monitoring device 6, and information for even the abnormality monitoring information of the distance L ₁ ~L _N in addition to the information of the reflection wavelength of the reflection portion R ₁ to R _N It is supposed to do. And, these reflection parts R ₁ ~
As R _N , any of those shown in FIGS. 2 and 3 can be applied.

Further, the trunk line coupler 7 installed in the station building 1
Is the inspection light hν emitted from the monitoring device 6 as in FIG.
Is transmitted to any of the trunk optical fiber lines and transmitted, and the returning reflected light Rν is transmitted to the monitoring device 6. The monitoring device 6 includes a light projecting unit 8 for emitting the inspection light hν and a light receiving unit 9 for receiving the reflected light Rν.
And a control unit 10 that monitors and controls whether or not an abnormality has occurred,
A bidirectional optical coupler 11 is provided, and the details of each of these components will be described below in this embodiment.

The configuration of the monitoring device 6 will be described with reference to FIG. In FIG. 13, parts that are the same as or correspond to those in FIG. 4 are indicated by the same symbols. Receiving unit 9, and the photoelectric conversion elements 9 _b for receiving and photoelectrically converting the reflected light Rν transmitted from mains coupler 7 via the bidirectional optical coupler 11, a photoelectric conversion output from the photoelectric conversion element 9 _b And an A / D converter 9 _b for converting the signal into digital data. Control unit 10
Incorporates a microcomputer for analyzing the presence or absence of abnormality based on the digital data output from the A / D converter 9 _b . The light projecting unit 8 includes the branch fiber lines W ₁ to
W _N in the wide wavelength range including the reflection wavelength of provided by that reflective portion R ₁ to R _N light (e.g., white light) and the light source 8 _a for emitting a very time width small pulse light, the pulse Wavelength tunable filter 8 for variably setting the light transmission selection wavelength
have _b . Then, the pulse drive circuit 10 _c causes the light source 8 _a to emit pulsed light in accordance with the instruction of the control unit 10, and the wavelength setting circuit 10 _b also controls the transmission selection wavelength of the wavelength tunable filter 8 _b in accordance with the instruction of the control unit 10. To do.

The operation of this embodiment will be described below. First, as the reflection portion R ₁ to R _N in FIG. 12, FIGS. 2 (a) or (b) in as shown, a single reflection wavelength specific to each lambda ₁
A monitoring system in which ~ λ _N is set will be described. FIG.
As shown in 4 (a), causes pulse turns on the light source 8 _a in synchronization with the appropriate time t _1, t ₂ ~t _N, in accordance with the these times, the permselective wavelength of the wavelength tunable filter 8 _b By sequentially changing the reflection wavelengths λ _{1 to} λ _N corresponding to the reflection wavelengths λ _{1 to} λ _N , the inspection light hν, which is pulsed light having a single wavelength λ _{1 to} λ _N , is emitted to the bidirectional optical coupler 11.

As a result, each pulsed light in the inspection light hν is
Specific reflection part R₁~ R_NIs reflected by the reflected light Rν
Becomes photoelectric conversion element 9_aIncident on. Where each reflection
Department R ₁~ R_NThe inspection light h
ν is the passive branch element 5_bIncident from each reflection part R₁~ R_N
The wavelength is selected by and the reflected pulsed light of each wavelength is returned.
The time required to reach the branch line fiber line W₁~ W_Nevery
Different to For example, the reflection part R₁Wavelength λ reflected at₁of
Time required for pulsed light τ₁Is a branch fiber line W₁Setting
L is a constant distance₁, And the speed of light is c, τ₁= 2 x L₁/ C
And the time required for each of the remaining pulsed light is shown by a general formula.
If, τ_i= 2 x L_iIt is represented by / c. Moreover, all the waves
Optical path (long trunk optical fiber) through which long pulsed light propagates in common
Track 3_b(Including others)_cTosure
For example, the pulsed light of each wavelength is converted into the photoelectric conversion element 9_aUntil it hits
The propagation delay time at_i= Δc + τ_i= Δ_c+2 x L_i/ C becomes (2). Therefore, the photoelectric conversion element 9_aIs the pal of each wavelength
Timing of receiving the light beam (pulse light of the reflected light Rν)
Is the same as the inspection light hν shown in FIG.
The time shifts as shown in (b). Photoelectric conversion element 9_aIs
These pulsed lights are photoelectrically converted into an A / D converter 9_bAnd control
Output to the control unit 10 and further the A / D converter 9_bIs a photoelectric conversion element
Child 9_aThe photoelectric conversion signal output from the
It is A / D converted and transmitted to the control unit 10. And the control unit
10 is a photoelectric conversion element 9_aWhen receiving photoelectric conversion signal from
Time and the emission time of the pulsed light in the inspection light hν,
Propagation delay time of pulsed light with different wavelength Δ_iAnd then on
From the digital data, the presence or absence of reflected pulsed light and its wavelength
To judge. And all wavelengths λ₁~ Λ_Nabout
The pulsed light is measured and the propagation delay for each wavelength is
Delay time Δ_iAnd the time data registered in advance
If there is a match that satisfies the criteria, all branch line files
Bar track W₁~ W_NIs determined to be normal.

For example, to describe the abnormality monitoring of the branch fiber line W ₁ as a representative, as shown in FIGS. 14A and 14B, the time at which the pulsed light of wavelength λ ₁ is emitted is t ₁ , while The time at which the reflected pulsed light of the same wavelength λ ₁ is received is t ₁ + Δ ₁ , and the control unit 10 detects the light reception time t ₁ + Δ ₁ based on the generation time of the photoelectric conversion signal, Know the propagation delay time Δ ₁ . I know the other wavelength λ _i Similarly, each unique propagation delay time Δ _i also. The measurement accuracy of the propagation delay time delta _i, each branch fiber line W ₁ ~
Although it depends on the length of W _N , it can be improved by using a timer, a microprocessor, or the like that counts at a high-speed clock frequency.

On the other hand, when an abnormality such as a break occurs in any of the branch fiber lines W _{1 to} W _N , FIG.
As shown in, the reflected pulse light corresponding to the abnormality of the generated branch fiber lines can not return to the photoelectric conversion elements 9 _a, the control unit 10 determines abnormality from the missing digital data to such pulsed light, Further, the branch fiber line in which the abnormality has occurred is identified based on the wavelength of the missing digital data.

[0098] Next, the case of monitoring system for applying the reflective portion R ₁ to R _N reflection wavelength is set for each plurality respectively as shown in FIG. 2 (c) or FIG. 3 (d) explain.

As typical examples, the wavelengths λ ₁ , λ ₂ , λ ₃
With using the inspection light hν of three kinds of pulse light, reflective portion R ₁ to R _N each, such three reflection wavelength lambda _1, lambda _2, as set by the combination of lambda ₃ To do. That is, seven (N = 2 ³ −1 = 7) reflecting portions R ₁
The to R _7, and if you attached to different positions of the distance L ₁ ~L ₇ of the middle seven branch fiber line W ₁ to _W-7. Further, combinations of reflection wavelengths set in the reflection parts R _{1 to} R ₇ are as shown in the table of FIG.
_It is assumed that ₁ is set to all the reflection wavelengths λ ₁ , λ ₂ and λ ₃ and the remaining reflection portions R _{2 to} R ₇ are set to the reflection wavelengths indicated by “1” in the figure.

Next, the abnormality monitoring operation will be described. First, as shown in FIG. 16 (a), by controlling the light source _8a and the wavelength tunable filter _8b in the same manner as above, pulses having single wavelengths λ ₁ , λ ₂ and λ ₃ and time-divided respectively The inspection light hν composed of light is emitted (emission times t ₁ , t ₂ ,
t ₃ ). On the other hand, the reflected pulsed light reflected by each of the reflectors R _{1 to} R ₇ and detected by the photoelectric conversion element 9 _a is as shown in FIG.
As shown in FIG. 6 (b), a plurality of wavelengths are provided for each wavelength λ ₁ , λ ₂ , and λ ₃ . For example, when the inspection light hν of the wavelength λ ₁ is emitted, the four reflected pulse lights from the reflection parts R ₁ , R ₃ , R ₅ , and R ₇ return (see FIG. 15), and the reflection part R
_Since the installation distances of ₁ , R ₃ , R ₅ , and R ₇ are different,
As shown in (b), the propagation delay times Δ ₁ , Δ ₂ , Δ ₃ ,
Return in time division (without overlapping) according to Δ ₇ .

The photoelectric conversion element 9 _a photoelectrically converts the reflected pulsed light, and the A / D converter 9 _b
Converts the photoelectric conversion signals into digital data and outputs the digital data to the control unit 10. Therefore, the control unit 10 identifies the combination of the reception time of the reflected pulsed light and the digital data for each wavelength, and further detects the missing wavelength. By detecting the presence or absence of digital data of the branch line fiber line W
The presence or absence of abnormality in _{1 to} W ₇ and the branch fiber line with abnormality are determined.

As described above, according to this embodiment, the information on the distance from the passive branch element to the reflecting portion attached to each branch fiber line is taken into consideration to further improve the abnormality monitoring accuracy. You can In addition, as a representative example, the case where each reflection part is identified by the combination of three kinds of reflection wavelengths λ ₁ , λ ₂ , and λ ₃ has been described. It is appropriately determined according to the number of parts and the like, and the method of combining these reflection wavelengths is also appropriately determined.

[0103] Also, FIG. 15 and as shown in FIG. 16, a plurality of types of reflection wavelength lambda ₁ that decided the reflective portion R ₁ to R _N pre
Having identified of a combination of to [lambda] _N, it is possible to reduce the kinds of setting wavelength of the pulse light to form an inspection light hv, the light source 8 _a and the wavelength selection filter 8 _b and the photoelectric conversion elements 9 _a such designs It is possible to obtain an effect that it becomes easy, or the reflected light Rν is converted into, for example, a binary code for each wavelength so as to be easily processed by the microcomputer or the like in the control unit 10.

[0104] In this embodiment, as shown in FIG. 13, but constitute a receiving portion 9 in the photoelectric conversion elements 9 _a A / D converter 9 _b, in place of such a configuration, the first The spectrum analyzer 14 disclosed in the second embodiment (see FIG. 6) may be applied. The Michelson interferometer 20 disclosed in the seventh embodiment (see FIG. 11) is also used.
The light receiving unit 9 including the FFT unit 21 and the like may be applied.

Furthermore, the light projecting section 8 in this embodiment is
As shown in FIG. 13, light in a wide wavelength range (for example, white light)
Is composed of _a pulsed light source 8 _a and a wavelength tunable filter 8 _b to generate a plurality of types of single wavelength pulsed light. Instead of such a configuration, the third embodiment (FIG. 7) is applied, and the same effect, that is, a plurality of types of single-wavelength pulsed lights are generated by performing pulse lighting every time the emission wavelength is changed. Good.

<Ninth Embodiment> Next, a ninth embodiment will be described with reference to FIG.
Will be explained together. Note that FIG. 17 shows the configuration of the monitoring device 6 installed in the station building, and the same or corresponding parts as in FIG. 13 are denoted by the same reference numerals. Further, the schematic configuration of the monitoring system in this embodiment is the same as that of FIG. 12, and the reflecting portion R ₁ provided in association with each branch fiber line W _{1 to} W _N.
Attached position of the to R _N is set from the passive splitter 5 _b to the distance L ₁ ~L _N of mutually different.

The configuration of the monitoring device 6 of this embodiment is shown in FIG.
If in contrast the monitoring device will be described as shown in, 17, the light receiving unit includes a photoelectric conversion element 9 _a for receiving and photoelectrically converting the reflected light Rν from bidirectional optical coupler 11, from the photoelectric conversion elements 9 _a An A / D converter 9 _b for converting the output photoelectric conversion signal into digital data and outputting the digital data to the control unit 10 is provided.

[0108] the light projecting unit, the broad wavelength band including the reflection wavelength of the reflected portion R ₁ to R _N provided in the branch line fiber line W ₁ to _W-N light (e.g., white light) extremely time width The light source 8 _a emits _a small pulsed light, and the pulse drive circuit 10 _c that turns on the light source 8 _a in accordance with a command from the controller 10. Therefore, the difference from the eighth embodiment is that the pulsed light in the wide wavelength range is directly used as the inspection light hν.
To use as.

The operation of this embodiment will be described below.
As reflected portion R ₁ to R _N in FIG. 12, FIGS. 2 (a) or (b) a single reflection wavelength lambda ₁ is unique to each as shown in ~
A monitoring system in which λ _N is set will be described. FIG.
As shown in (a), the light source 8 is synchronized with an appropriate time t _1.
By pulse-lighting _a , the inspection light hν composed of pulsed light in a wide wavelength range is emitted to the bidirectional optical coupler 11.

As a result, each pulsed light in the inspection light hν is
It is reflected in accordance with the reflection wavelength of the reflected portion R ₁ to R _N, as reflected light Rν incident on the photoelectric conversion element 9 _a. here,
Because attached position of each reflective portion R ₁ to R _N are different, the reflected test light hν is incident from the passive splitter 5 _b portion R ₁
To R _N at the time required to come back is wavelength selective and the reflected pulse light of each wavelength (propagation delay time) is different for each branch fiber line W ₁ to _W-N. Therefore, the timing at which the photoelectric conversion element 9 _a receives the pulsed light of each wavelength (the pulsed light of the reflected light Rν) is as shown in FIG. 18B with respect to the inspection light hν shown in FIG. 18A. The time will be off. Then, the photoelectric conversion element 9 _a converts these pulsed light into a photoelectric conversion signal and outputs the photoelectric conversion signal to the A / D converter 9 _b and the control unit 10, and the A / D converter 9 _b further converts the photoelectric conversion signal into digital data. A / D converted to and transmitted to the control unit 10.

The control section 10 propagates the reflected pulsed light of each wavelength λ _{1 to} λ _N from the reception time of the photoelectric conversion signal from the photoelectric conversion element 9 _a and the emission time t ₁ of the pulsed light in the inspection light hν. The delay time is measured, and the presence or absence of reflected pulsed light and its wavelength are determined from the digital data. All wavelengths λ
_If the pulsed light for _{1 to} λ _N is measured, and the propagation delay time for each wavelength and the pre-registered time data have a match satisfying a predetermined standard, all branch fiber lines It is determined that W _{1 to} W _N are normal.

On the other hand, when an abnormality such as a break occurs in any of the branch fiber lines W _{1 to} W _N , FIG.
As shown in, the reflected pulse light corresponding to the abnormality of the generated branch fiber lines can not return to the photoelectric conversion elements 9 _a, the control unit 10 determines abnormality occurrence from Missing digital data such pulsed light, Further, the branch fiber line in which the abnormality has occurred is identified and judged based on the wavelength of the missing digital data.

As described above, when the monitoring system in which the unique single reflection wavelengths λ _{1 to} λ _N are set as shown in FIG. Since it only needs to be emitted once, it can be monitored in a short time.
Furthermore, it is possible to improve the monitoring accuracy so determining the presence or absence of an abnormality, including information attached position of the reflective portion R ₁ to R _N.

[0114] In this embodiment, as shown in FIG. 17, but constitute a receiving portion 9 in the photoelectric conversion elements 9 _a A / D converter 9 _b, in place of such a configuration, the first The spectrum analyzer 14 disclosed in the second embodiment (see FIG. 6) is applied, and the control unit 10 compares the spectrum distribution data output from the spectrum analyzer 14 with the determination reference data to perform abnormality monitoring. It may be performed.

<Tenth Embodiment> Next, a tenth embodiment will be described with reference to FIG. First, FIG. 19 shows a configuration example of the monitoring system of this embodiment, and the same or corresponding portions as those in FIG. 12 are denoted by the same reference numerals. First, the structural features of the monitoring system of this embodiment will be described in comparison with the monitoring system of FIG.

[0116] monitoring system of FIG. 12, the passive branch elements one by one is provided in the trunk optical fiber line 3 _a to 3 _c, shown as a representative, is further connected to a dendritic the receiving branch element 5 _b An optical communication network having a configuration in which the subscriber terminal devices CM _{1 to} CM _N are connected to the ends of the plurality of branch fiber lines W _{1 to} W _N is monitored. That is, the dendritic optical communication network is
It has a one-stage configuration with respect to each trunk optical fiber line 3 _a to 3 _c.

On the other hand, in the monitoring system shown in FIG. 19, a passive branch element is further connected to the branch fiber line of the first stage, and a plurality of branch fiber lines connected in a dendritic manner to this passive branch element. An optical communication network having a structure in which subscriber terminal devices are connected to each of them is to be monitored. That is,
The purpose is to monitor anomalies in a multi-stage dendritic optical communication network. Further, FIG. 19 shows a multi-stage dendritic optical communication network having a two-stage configuration. As will be described later, this embodiment is capable of monitoring abnormalities in the dendritic optical communication network having two or more stages. Further, in the description of the monitoring system of this embodiment, a typical Representative examples, the trunk optical fiber line 3 _b of the passive splitter 5 first stage branch fiber line which is dendritic connected to _b W ₁₁ to _W-1N Then, the second branch fiber lines W _{21 to} W _2M, which are arborically connected to the passive branching element 5 _b2 provided on the branch fiber line W ₁₁ , will be described as monitoring targets.

The first branch fiber lines W _{11 to} W _1N have different distances L ₁₁ from the passive branch element 5 _b.
Reflectors R _{11 to} R _1N are provided at the positions of L ₁ to L _1N , and the passive branch element 5 _b2 is attached to the second branch fiber lines W _{21 to} W _2M.
From the reflection portion R ₂₁ to R _2M at a distance L ₂₁ ~L _2M with different respective mutually are attached, it is connected to the subscriber terminal device CM ₁ ~CM _M at the end of the branch line fiber line W ₂₁ to _W-2M There is. In the station building 1, monitoring devices 6 similar to those shown in FIG. 3 or FIG. 13 or FIG. 17 are installed, and these monitoring devices 6 and the trunk optical fiber lines 3 _{a to} 3 _c are connected to the trunk coupler 7.
Connected by.

First, a monitoring system to which the same monitoring device 6 as shown in FIG. 3 or FIG. 13 is applied will be described.
In addition, as the reflection parts R _{11 to} R _1N and R _{21 to} R _2M in FIG.
It is assumed that the unique single reflection wavelengths λ _{11 to} λ _1N and λ _{21 to} λ _2M are set respectively as shown in FIG. 2A or 2B.

[0120] The light source 8 _a in the monitoring apparatus 6 shown in FIG. 3, sequentially emits pulse light having a wavelength lambda ₁₁ to [lambda] _1N and lambda ₂₁ to [lambda] _2M itself. On the other hand, the light source 8 in the monitoring device 6 shown in FIG.
_a is the branch fiber line W ₁₁ to _W-1N and W ₂₁ to W-reflection portion is provided on _2M R ₁₁ to R _1N and R ₂₁ to R all reflection wavelength lambda ₁₁ to [lambda] _1N and lambda ₂₁ to [lambda] of _2M Light in a wide wavelength range including _2M (for example, white light) is emitted as pulsed light with an extremely small time width, and the wavelength tunable filter _8b varies the transmission selection wavelength in synchronization with the emission timing of these pulsed light. It is supposed to be set.

Then, by applying any one of these monitoring devices 6, as shown in FIG. 20 (a), a single-wavelength pulse light train of wavelengths λ _{11 to} λ _1N and subsequent wavelengths λ _{21 to} λ _2M. When the inspection light hν composed of the single-wavelength pulse light train of is transmitted through the bidirectional optical coupler 11, the reflecting portions R _{11 to} R _1N and R ₂₁ to
Since the installation positions of R _2M are different from each other and the second-stage reflecting portions R _{21 to} R _2M are provided farther than the first-stage reflecting portions R _{11 to} R _1N , The propagation delay time until returning to the photoelectric conversion element 9 _a is different for each pulsed light of the wavelength, and as _a result, the reflected light Rν that enters the photoelectric conversion element 9 _a.
Shows a pulsed light train as shown in FIG. Then, the pulsed light in the reflected light Rν is sequentially photoelectrically converted by the photoelectric conversion element 9 _a , and the A / D converter 9 _b outputs the photoelectric conversion signals sequentially output from the photoelectric conversion element 9 _a as digital data. A / D converted to and output to the control unit 10.

The control section 10 controls the reflection sections R _{11 to} R _1N and R ₂₁ to.
Input the data of all reflected pulsed light corresponding to R _2M ,
Further, if the propagation delay time of each reflected pulsed light is compared with the predetermined reference time data and the predetermined matching is satisfied, it is determined that there is no abnormality, while the branch fiber lines W _{11 to} W _1N if there is a breakage fault in any one of W ₂₁ to _W-2M and, as shown in FIG. 20 (c), the reflected pulse light corresponding to the abnormality of the generated branch fiber line is returned to the photoelectric conversion elements 9 _a Therefore, the control unit 10 determines the occurrence of an abnormality from the lack of the digital data of the pulsed light, and further identifies and determines the branch fiber line based on the wavelength of the missing digital data. Incidentally, FIG. 20C shows a case where the reflected pulsed light of the wavelength λ ₂₂ is not detected by the photoelectric conversion element 9 _{a as} a result of the presence of an abnormality such as a disconnection in the branch fiber line W ₂₂ of the second stage. ing.

Next, in a monitoring system to which a monitoring device 6 similar to that shown in FIG. 17 is applied, the reflecting portions R _{11 to} R _1N and R _{21 to} R _2M in FIG. (B)
The unique reflection wavelengths λ _{11 to} λ _1N , λ
_For abnormality monitoring when _{21 to} λ _2M is set,
Light source 8 _a in FIG. 17, the reflective portion R ₁₁ to R _1N and R ₂₁ to R _2M
Pulsed light in a wide wavelength range that includes all the reflection wavelengths λ _{11 to} λ _1N and λ _{21 to} λ _2M set to (white pulsed light)
Is emitted as inspection light hν. In this case, FIG.
Similarly to the cases shown in (a) to (c), it is possible to obtain information on the spectrum for each wavelength and the distance for each reflecting section from the reflected light Rν, and the control section 10 monitors the abnormality based on these information. I do. Further, it is possible to monitor the abnormality by emitting only one inspection light hν.

In the light receiving section 9 in the monitoring device 6 of FIG. 3 or FIG. 13 or FIG. 17, the reflected pulsed light reflected and returned is directly photoelectrically converted by the photoelectric conversion element 9 _a . However, as another configuration, _a wavelength tunable filter is provided in front of the photoelectric conversion element 9 _a as shown in FIG.
Inspection light h of a pulsed light train for each wavelength as shown in 0 (a)
By repeatedly emitting ν, reflection wavelengths λ ₁₁ to λ _1N , λ ₂₁ to
The wavelength tunable filter may be drive-controlled so that the transmission selection wavelength corresponding to λ _2M is sequentially switched in synchronization with the repetition cycle. When such a wavelength tunable filter is provided, one reflected pulse light is detected for each repetition period, but substantially, FIG. 18B or 18C is used.
Alternatively, similarly to the case shown in FIG. 20 (b) or (c), since the pulsed light corresponding to the reflection wavelengths λ _{11 to} λ _1N and λ _{21 to} λ _2M can be detected, the control unit 10 controls the reflection light. Based on the data corresponding to the pulsed light and the transmission delay time, the presence / absence of an abnormality and the branch fiber line having the abnormality can be identified.

As another configuration of the light receiving section 9, the reflected light Rν returning via the both-side optical coupler 11 is received and analyzed by a spectrum analyzer, and based on the spectrum distribution data output from this spectrum analyzer. You may make it the control part 10 monitor abnormality.

Furthermore, as the configuration of another light receiving portion 9, the light receiving portion as described in the seventh embodiment (see FIG. 11) may be applied. That is, the reflected light Rν returning via the bidirectional optical coupler 11 is caused to interfere with the Michelson interferometer 20, the interference light is photoelectrically converted by the photoelectric conversion element 9 _a , and the digital data is converted by the A / D converter 9 _b. Alternatively, the FFT unit 21 may perform discrete fast Fourier transform on the digital data to generate spectrum distribution data, and the control unit 10 may perform abnormality monitoring based on the spectrum distribution data.

<Embodiment 11> Next, an eleventh embodiment will be described. This embodiment is, like the tenth embodiment (see FIG. 19), a monitoring system for monitoring an abnormality in a multiple-stage dendritic optical communication network. However, the difference from the tenth embodiment is that the respective reflection portions attached to the plurality of branch fiber lines to be monitored are the same as those shown in FIG. 2 (c) or FIG. 3 (d). , And each has a plurality of reflection wavelengths.

As a typical example, it is assumed that the number of branch fiber lines in the first stage and the number of branch fiber lines in the second stage are each seven, and they are attached to the branch fiber lines W _{11 to} W ₁₇ in the first stage. As shown in the table of FIG. 21, the reflection wavelengths of the reflecting portions R _{11 to} R ₁₇ are composed of three kinds of combinations of wavelengths λ ₁₁ , λ ₁₂ , and λ ₁₃ , and the second branch fiber line W _21. Similarly, the reflection wavelengths of the reflection parts R _{21 to} R ₂₇ attached to W ₂₇ to
It is assumed to consist of three kinds of combinations of wavelengths λ ₂₁ , λ ₂₂ , and λ ₂₃ . Furthermore, these wavelengths λ ₁₁ , λ ₁₂ ,
It is assumed that λ ₁₃ , λ ₂₁ , λ ₂₂ and λ ₂₃ are wavelengths having mutually different mutually exclusive relations. For example, it is assumed that the reflection wavelengths of the reflection part R ₁₁ are set to the wavelengths λ ₁₁ , λ ₁₂ , and λ ₁₃ , and the remaining reflection parts are set to the reflection wavelength indicated by “1” in the same 21.

On the other hand, in the station building 1, a monitoring device 6 similar to that shown in FIG. 3, FIG. 13 or FIG.
It is connected to the trunk optical fiber line 3 _a to 3 _c through. When applying the monitoring device 6 shown in FIG. 3, the wavelength lambda ₁₁ to [lambda] _1N and lambda ₂₁ ~ source 8 _a which is built on its own
The pulsed light of λ _2M is emitted sequentially. On the other hand, when the monitoring device 6 shown in FIG. 13 is applied, the built-in light source 8
_a is reflective portion R ₁₁ to R _1N and R ₂₁ to R all reflection wavelength lambda ₁₁ to [lambda] _1N and lambda ₂₁ to [lambda] _2M encompassing broad wavelength band of light (e.g., white light) extremely time width of _2M And pulsed light is emitted, and the wavelength tunable filter 8 _b changes the transmission selection wavelength in synchronization with the emission timing of these pulsed lights. Therefore, whichever monitoring device 6 is applied,
As shown in FIG. 22A, each of the inspection lights Rν transmitted to the predetermined main optical fiber line 3 _b via the bidirectional optical coupler 11 has a unique single wavelength and time-divided pulses. It becomes a train of light (in the figure, the emission time of each pulsed light is shown as t ₁ , t ₂ , t ₃ , t ₄ , t ₅ , t ₆ ).

Next, the monitoring device 6 shown in FIG. 3 or FIG.
The abnormality monitoring operation when is applied will be described. First, FIG.
As shown in FIG. 2 (a), when the inspection light Rν composed of a pulse light train of a unique single wavelength is emitted, for example, the pulse light of the wavelength λ ₁₁ emitted at the emission time t ₁ is reflected. The four reflected pulsed lights from the sections R ₁₁ , R ₁₂ , R ₁₃ , and R ₁₄ are returned (see FIG. 21), and these reflected sections R
_Since the installation distances of ₁₁ , R ₁₂ , R ₁₃ , and R ₁₄ are different, FIG.
As shown in 2 (b), and reaches the photoelectric conversion elements 9 _b in a time division (not overlapping) in accordance with their propagation delay time. In other words, so that the reflected pulse light reflected by the reflection portion that is attached to the nearest position from the passive splitter 5 _b is returned to the fastest photoelectric conversion element 9 _b. Then, similarly for the reflected pulsed light of the remaining wavelengths, the reflecting portions R _{11 to} R ₁₇ ,
The light reaches the photoelectric conversion element 9 _b with a propagation delay time corresponding to the installation distance of R _{21 to} R ₂₇ .

The photoelectric conversion element 9 _a photoelectrically converts these reflected pulse lights, and the A / D converter 9 _b converts these photoelectric conversion signals into digital data and outputs the digital data to the control unit 10. The control unit 10 identifies the combination of the reception time of the reflected pulsed light and the digital data for each wavelength, and further detects the presence / absence of digital data for the missing wavelength to detect an abnormality in the branch fiber lines W _{1 to} W ₇ . The presence or absence and the abnormality of the branch fiber line are judged.

Next, the case of applying the monitoring device 6 shown in FIG. 17 will be described. The built-in light source 8
_a is reflective portion R ₁₁ to R _1N and R ₂₁ to R all reflection wavelength lambda ₁₁ to [lambda] _1N and lambda ₂₁ to [lambda] _2M encompassing broad wavelength band of light (e.g., white light) extremely time width of _2M And emitted as narrow pulsed light, which becomes the inspection light hν. In this case also, the inspection light h
Each wavelength component included in ν has a predetermined reflection portion R _{11 to} R _1N.
And R _{21 to} R _2M select and reflect the wavelength.
Since the propagation delay time differs according to the difference in the installation distance of the reflecting portions R _{11 to} R _1N and R _{21 to} R _2M , the reflected light Rν is shown in FIG.
The same as in (b). Therefore, even if any of the monitoring devices 6 shown in FIG. 3, FIG. 13 or FIG.
Equivalent reflected light Rν is obtained.

Here, noteworthy points of this embodiment will be described. Note that this is a point of interest that can be obtained in common when any of the monitoring devices 6 of FIG. 3, FIG. 13 or FIG. 17 is applied.

As described above, the digital data output from the A / D converter 9 _b has two characteristic parameters of the wavelength of each reflected pulsed light and the propagation delay time. Therefore, the control unit 10 of this embodiment uses the above equation (2).
The length L _i of each branch fiber line is calculated back from the propagation delay time Δ _i of each reflected pulse based on the above equation, and as shown in the principle diagram of FIG. 23, reflection is performed on the two-dimensional coordinates of this length L _i and wavelength. A process of plotting information on the presence or absence of pulsed light is performed. More specifically, a random access memory that presets a storage area in which the length L _i and the wavelength can be arranged in a matrix is provided in the control unit 10, and the presence or absence of digital data corresponding to each reflected pulse light is provided. Are allocated to this matrix-arrangeable storage area. A logical "1" is assigned when digital data exists, and a logical "0" is assigned when digital data does not exist.

When the digital data corresponding to each of the detected reflected pulses is represented by a two-dimensional matrix array, the same result as shown in the table of FIG. 21 is obtained when all branch fiber lines have no abnormality. . The control unit 10 compares the data of FIG. 21 stored in advance with the data of the above two-dimensional matrix array, and if they match each other, all branch fiber lines are in a normal state, and there is data that does not match. If so, the branch fiber line having the abnormality is determined from the coordinate information (wavelength and distance) of the matrix arrangement of the mismatched data.

By thus allocating the data corresponding to the reflected pulsed light by using such a matrix arrangement, it is possible to easily determine the presence / absence of an abnormality and specify the branch fiber line in which the abnormality exists.

Further, in this embodiment, the abnormality monitoring of the two-stage dendritic optical communication network has been described. However, the processing by the matrix arrangement can be easily applied to the abnormality monitoring of the three-stage or more dendritic optical communication network. Therefore, this embodiment exhibits extremely excellent expandability.
Also, by taking into account the information on the distance from the passive branch element to the reflection part attached to each branch fiber line,
It is possible to further improve the accuracy of abnormality monitoring.

The light receiving portion 9 in the monitoring device 6 of FIG. 3 or FIG. 13 or FIG. 17 has a structure in which the reflected pulse light reflected and returned is directly photoelectrically converted by the photoelectric conversion element 9 _a . However, as another configuration, _a wavelength tunable filter is provided in front of the photoelectric conversion element 9 _a as shown in FIG.
Inspection light h of a pulsed light train for each wavelength as shown in 0 (a)
By repeatedly emitting ν, reflection wavelengths λ ₁₁ to λ _1N , λ ₂₁ to
The wavelength tunable filter may be drive-controlled so that the transmission selection wavelength corresponding to λ _2M is sequentially switched in synchronization with the repetition cycle. When providing such a wavelength tunable filter is comprised in and detecting the reflected pulsed light of one each repetition period, as show in substantially FIG. 22 (b), the reflection wavelength lambda ₁₁ ~ Since the pulsed lights corresponding to λ _1N and λ _{21 to} λ _2M can be detected, the control unit 10 performs matrix arrangement processing of the wavelengths of these reflected pulsed lights and the distance corresponding to the transmission delay time, and By comparing with the reference data, it is possible to identify the presence or absence of an abnormality and the branch fiber line having the abnormality.

As another configuration of the light receiving section 9, the reflected light Rv returning via the both-side optical coupler 11 is received and analyzed by a spectrum analyzer, and controlled based on the spectrum distribution data output from this spectrum analyzer. The unit 10 may monitor the abnormality.

Furthermore, as another structure of the light receiving section 9, the light receiving section as described in the seventh embodiment (see FIG. 11) may be applied. That is, the reflected light Rν returning via the bidirectional optical coupler 11 is caused to interfere with the Michelson interferometer 20, the interference light is photoelectrically converted by the photoelectric conversion element 9 _a , and the digital data is converted by the A / D converter 9 _b. Alternatively, the FFT unit 21 may perform discrete fast Fourier transform on the digital data to generate spectrum distribution data, and the control unit 10 may perform abnormality monitoring based on the spectrum distribution data.

Further, as shown in FIG. 2 (c) or FIG. 3 (d), a dendritic optical communication network in which each branch line has a reflecting portion in which a plurality of reflection wavelengths are set respectively. Even in the monitoring system, wavelength and propagation delay time (distance)
It is obvious that the above matrix array processing can be performed using as a feature parameter.

Furthermore, in this embodiment described with reference to FIG. 19, the reflection wavelength λ set in the reflecting portions R _{11 to} R _1N attached to the first branch fiber line group. _{11 to} λ _1N and the reflection wavelength λ set to the reflection parts R _{21 to} R _2M attached to the second branch fiber line group.
_{21 to} λ _2M are set to the wavelengths of different wavelength bands separately to perform the data processing of the matrix array as shown in FIG. 23, but the present invention is not limited to this and the monitoring target is not limited to this. Each branch line fiber line,
Other combinations may be used as long as they can be identified by the installation distance and the reflection wavelength. For example, if the installation distances of the respective reflection parts are different, two reflection wavelengths that are equal to each other are set.
The above reflectors can be used at the same time.

<Twelfth Embodiment> Next, a twelfth embodiment will be described. In this embodiment, in the same manner as shown in FIG. 12, the branch fiber line W ₁ to W-each reflector of the _N R ₁ to R _N
Are different distances L _{1 to} L from the passive branch element 5 _b.
Regarding the monitoring system attached to _N ,
The monitoring device 6 installed in the above has a configuration shown in FIG. Note that among the constituent elements shown in FIG. 24, the same or corresponding constituent elements as those shown in FIGS. 4 and 9 are designated by the same reference numerals.

First, the structure of the monitoring device 6 of this embodiment will be described with reference to FIG. 24. The light projecting unit includes the reflecting units R _{1 to} R.
A light source 8 _a that continuously emits light in a wide wavelength range including reflection wavelengths λ _{1 to} λ _N of _N (for example, white light) at a constant emission intensity, and a transmission selection wavelength of light emitted from the light source 8 _a. And a wavelength tunable filter 8 _b that continuously sweeps and changes
The wavelength setting circuit 10 _b performs sweep control for sweeping and changing the transmission selection wavelength of the wavelength tunable filter 8 _b . Then, the light transmitted through the wavelength tunable filter 8 _b becomes the inspection light hν and is transmitted to the trunk coupler via the bidirectional optical coupler 11. The change range of the transmission selected wavelength, it is set to a wide wavelength range than with encompasses reflection wavelength lambda ₁ to [lambda] _N of the reflection portion R ₁ to R _N. Further, this transmission selection wavelength changes in proportion to time t so as to satisfy the following expression (3), and all the reflection wavelengths λ _{1 to} λ _N are set during a predetermined period T (hereinafter, T Is called the sweep period). However, λ ₀ is the first wavelength (hereinafter,
Δ is a constant wavelength change rate with respect to time, and for time t, 0 ≦ t ≦ T.

Λ (t) = λ ₀ + δ × t (3) On the other hand, in the light receiving section 9, the reflected light Rν returning through the bidirectional optical coupler 11 is incident and the transmission selection wavelength of the reflected light Rν is selected. Of the wavelength tunable filter 17 which changes so as to continuously sweep, the photoelectric conversion element 9 _a which photoelectrically converts the light transmitted through the wavelength tunable filter 17, and the photoelectric conversion signal output from the photoelectric conversion element 9 _a into digital data. An A / D converter 9 _b for converting and outputting to the control unit 10 is provided. Then, the wavelength setting circuit 18 performs sweep control for sweeping and changing the transmission selection wavelength of the wavelength tunable filter 17. The change range of the transmission selected wavelength of the wavelength setting circuit 18, the reflective portion R ₁ to R reflection wavelength of the _N lambda ₁ to [lambda] _N
Is set to a wider wavelength range than that. Furthermore,
The relationship of the following expression (4) is set with respect to the above expression (3).
That is, the change in the transmission selection wavelength of the wavelength tunable filter 17 with respect to the change in the transmission selection wavelength of the wavelength tunable filter 8 _b is
It is set with a certain time delay Δ (hereinafter referred to as a phase difference).

Λ (t) = λ ₀ + δ × (t−Δ) (4) Further, this phase difference Δ is equivalent to the propagation delay time Δ _{i for} each wavelength shown in the equation (2). Further, the phase difference Δ is set by the phase adjuster 23 provided between the controller 10 and the wavelength setting circuits 10 _b and 18. That is, when the control unit 10 commands the phase adjustment unit 23 to start the above sweep control, the phase adjustment unit 23 first causes the wavelength setting circuit 10 _b to start the sweep control of the wavelength tunable filter 8 _b , and then In addition, the sweep control of the wavelength tunable filter 8 _b by the wavelength setting circuit 10 _b is started when the phase difference Δ has elapsed.

Next, the operation of this embodiment having such a configuration will be described. First, when the control unit 10 commands the phase adjustment unit 23 to start the above-mentioned sweep control, the wavelength tunable filter 8 is supplied under the control of the phase adjustment unit 23 and the wavelength setting circuit 10 _b as shown in FIG. The transmission selection wavelength of _b is
It changes continuously in proportion to the passage of time. Incidentally, the sweep control is performed N times corresponding to the number N of the branch fiber lines W _{1 to} W _{N to be} monitored, and the start times thereof are t ₁₁ , t ₂₁ to t in FIG. _Shown as _N1 .

Further, the phase adjusting unit 23 and the wavelength setting circuit 1
According to the control of No. 8, as shown in FIG. 25B, the transmission selection wavelength of the wavelength tunable filter 17 continuously changes in proportion to the passage of time. As shown in FIG. 7B, the transmission selection wavelengths of the wavelength tunable filter 17 have their own phase differences Δ ₁ and Δ ₁ on the basis of the start times t ₁₁ and t _{21 to} t _N1 , respectively.
Time points t ₁₁ + Δ ₁ , t ₂₁ + Δ ₂ ~ delayed by Δ _{2 to} Δ _N
Sweep control is performed from t _N1 + Δ _N. Where the phase difference Δ
₁ is the inspection light hν emitted from the wavelength tunable filter 8 _b.
There propagation delay time required for the reflected light Rν selected reflected by the reflective portion R ₁ reaches the wavelength tunable filter 17, the phase difference delta _2, the inspection light hν emitted from the wavelength-variable filter 8 _b is reflected portion R ₂ Propagation delay time required for the reflected light Rν to be selectively reflected by and reach the wavelength tunable filter 17,
In the same manner, finally, the phase difference Δ _N is the propagation delay required until the inspection light hν emitted from the wavelength tunable filter 8 _b is selectively reflected by the reflector R _N and the reflected light Rν reaches the wavelength tunable filter 17. It is equal to time. Since annexed distance of the reflective portion R ₁ to R _N is known in advance, the phase difference delta ₁ is previously calculated on the basis of these attached distances, data Δ ₂ ~Δ _N is stored in the phase adjusting unit 23 The phase adjustment unit 23 uses the data shown in FIG.
The phase differences Δ ₁ and Δ _{2 to} Δ _N shown in (b) are set.

When the wavelength tunable filters 8 _b and 17 are swept in this way, first, in the first sweep control of FIGS. 25A and 25B, the reflection wavelength λ ₁ at a certain time t ₁₂ . Suppose that the inspection light hν equal to is emitted from the wavelength tunable filter 8b, the inspection light hν is selectively reflected by the reflection part R ₁ and becomes the reflected light Rν, which is the propagation delay time required to reach the wavelength tunable filter 17. Since the phase difference Δ ₁ is equal, the transmission selection wavelength of the tunable filter 17 is exactly λ.
The reflected light Rν enters in synchronization with the time point t ₁₃ when it becomes _1, and is transmitted to the photoelectric conversion element 9 _a . In this way, the point in time when the reflected light Rν of the reflection wavelength λ ₁ enters the wavelength tunable filter 17 and the point in time when the transmission selection wavelength of the wavelength tunable filter 17 becomes λ ₁ are synchronized (t ₁₃ −t ₁₁ ) - (t ₁₂ -
It is also clear from the fact that the relational expression of t ₁₁ ) = Δ ₁ holds. Further, for the reflected light Rν of the remaining wavelengths except the wavelength λ ₁ , the transmission selection wavelength of the wavelength tunable filter 17 is not set in synchronization in this way, so in the end, in the first sweep control, As shown at time t ₁₃ in 25 (c), only the photoelectric conversion signal of the reflected light Rν of the wavelength λ ₁ is output from the photoelectric conversion element 9 _b . Then, the photoelectric conversion signal is converted into digital data by the A / D converter 9 _b and is supplied to the control unit 10. When the digital data is supplied to the control unit 10, the reflection unit R ₁ is attached. It is determined that the branch fiber line W ₁ is normal, and conversely, when this digital data is not supplied, it is determined that the branch fiber line W ₁ has an abnormality such as a disconnection.

[0150] Next, FIG. 25 (a) (b) to a second sweep control shown, i.e., starts the sweep control of the tunable filter 8 _b from the time t _21, the phase difference Δ that point t _{21 When} the sweep control of the wavelength tunable filter 17 is started from the time point (t ₂₁ + Δ ₂ ) after the lapse of ₂ times, the reflection selectively reflected by the reflecting section R ₂ is the same as the synchronization principle in the case of the first sweep control described above. the time t ₂₃ to the reflected light Rν wavelength lambda ₂ is incident on the wavelength tunable filter 17, will be the time t ₂₃ to permselective wavelength of the tunable filter 17 is set to lambda ₂ match (synchronized), the result As shown in FIG. 25C, at time t ₂₃ , only the reflected light Rν of the wavelength λ ₂ is converted into the photoelectric conversion signal by the photoelectric conversion element 9 _a , and the photoelectric conversion signal is further converted into the A / D converter 9 _b. Is converted into digital data by and supplied to the control unit 10. Be paid.

When this digital data is supplied, the control unit 10 determines that the branch fiber line W ₂ to which the reflecting section R ₂ is attached is normal. On the contrary, when this digital data is not supplied, , It is determined that the branch fiber line W ₂ has an abnormality such as a disconnection.

Thus, the branch fiber lines W ₁ and W ₂
Abnormality has been described as a representative monitoring relating, Similarly for abnormality monitoring of the remaining branch line fiber line W ₃ to _W-N, is performed individually by the N-th each sweep control from the third. Incidentally, FIG. 25 (a) ~ In the N-th sweep control (c), the with sweep control by the wavelength tunable filter 8 _b is started from the time t _N1, reflective portion at time t _N2 R _N is the output from the reflection wavelength lambda _N equal output light hν is tunable filter 8 _b, whereas, starts from the time the sweep control by the wavelength tunable filter 17 has passed the phase difference delta _N the time point _{t N1 (t N1 + Δ N} ) , At time t _N3 , the transmission selection wavelength of the wavelength tunable filter 17 becomes λ _N , so that the reflected light Rν of the wavelength λ _N is detected. Thus, according to this embodiment, it is monitored into a plurality of branch fiber lines, each reflector of the different reflection wavelengths λ ₁ ~λ _N R ₁ ~R _N respectively different distances L ₁ ~
The emission light is attached to L _N , the wavelength of the emission light hν is continuously changed as described above, and the phase difference Δ _{1 to} Δ _N corresponding to the distances L _{1 to} L ₂ is applied to the emission light. When continuously vary the transmission selected wavelength of the reflected light Rν from a predetermined time delayed from the output time point of hv, the pulse light of each reflected light lambda ₁ to [lambda] _N set in the reflective portion R ₁ to R _N Can be detected. Consequently, whether or not there is an abnormality in the branch fiber lines W _{1 to} W _N can be determined by the presence or absence of detection of each pulsed light, and when no pulsed light is detected,
The branch fiber line in which the abnormality has occurred can be specified based on the wavelength and the phase difference regarding the pulsed light.
Moreover, such a monitoring system can be realized with a relatively simple configuration.

[0153] Incidentally, in this embodiment, respectively has been described a case of applying the reflective portion R ₁ to R _N, which already has a unique single reflection wavelength, and FIG. 2 (c) or FIG. 3 As shown in FIG. 12, a reflecting portion having a plurality of reflecting wavelengths set as shown in (d) and having different reflecting wavelengths is attached to each branch fiber line as shown in FIG. Alternatively, the sweep control may be performed based on the same principle as in FIG. 25. In this case, one pulsed light of a single wavelength is not detected every sweep period T as shown in FIG. 25C, but as shown in FIG. A pulsed light group of a plurality of reflection wavelengths of each reflection unit is detected for each. Therefore, this embodiment can also be applied to a monitoring system that uses a reflecting portion having a plurality of reflection wavelengths set.

In this embodiment, the abnormality monitoring system for the one-stage optical communication network has been described as shown in FIG. 12. However, the two-stage optical communication network shown in FIG. It can also be applied to an abnormality monitoring system for an optical communication network having the above-mentioned number of stages. That is, in the case of an abnormality monitoring system for an optical communication network having a plurality of stages, the phase difference Δ is determined based on the attachment position of the reflecting portion attached to the branch line fiber line of two or more stages.
Is calculated in advance and the phase difference Δ of the sweep cycle of the wavelength tunable filter on the emitting side and the light receiving side is controlled based on the same principle as in FIGS.

Furthermore, the eighth embodiment (see FIG. 15) and the eleventh embodiment (see FIGS. 21 and 23).
As described above, the control unit 10 may process both information about the installation distance of each reflection unit and the reflection wavelength of each reflection unit as data of a matrix array.

<Thirteenth Embodiment> Next, a thirteenth embodiment will be described with reference to FIG. Incidentally, FIG. 26 shows the configuration of the monitoring device 6 provided in the station building, and is applied to all the monitoring devices 6 described in the first to twelfth embodiments.
Further, in FIG. 26, constituent elements that are the same as or correspond to the constituent elements of the monitoring device in the first to twelfth embodiments are denoted by the same symbols.

The characteristic features of this embodiment will be described in comparison with the above-mentioned first to twelfth embodiments.
In the bidirectional optical coupler 11 in the monitoring device 6 in the twelfth embodiment, the light projecting unit 8 is connected to the first port, the light receiving unit 9 is connected to the second port, and the trunk line coupler 7 is connected to the third port. Is
The remaining fourth port is simply terminated. Then, when the inspection light hν emitted from the light projecting unit 8 is incident on the first port, it is transmitted to the trunk line coupler 7 through the third port and is transmitted through the trunk line coupler 7. Reflected light R
ν enters the third port and further enters the light receiving unit 9 through the second port. Therefore, the fourth
The port is virtually unused for anomaly monitoring.

On the other hand, in this embodiment, as shown in FIG. 26, the reflecting portion 24 is connected to the fourth port, and the light reflected by this reflecting portion 24 (hereinafter referred to as internal reflected light) is used. Is also detected by the light receiving unit 9, and the control unit 10 analyzes the information of the internal reflected light to realize a more reliable abnormality monitoring system.

This embodiment will be described in more detail. In FIG. 26, among the ports provided in the bidirectional optical coupler 11, the light projecting section 8 is provided at the first to third ports P ₁ , P ₂ and P _3. The light receiving section 9 and the trunk line coupler 7 are connected as shown in the drawing, and the reflecting section 24 is connected to the fourth port P ₄ . For example, in the bidirectional optical coupler 11 using an optical fiber, optical branching coupling is performed by using crosstalk (crosstalk) that occurs when a plurality of (two in the figure) optical fibers are brought close to each other. This is done by fusing the optical fibers together, or by making the cladding layer thin and adhering the optical fibers together. Therefore, the inspection light hν incident on the first port P ₁ is transmitted to the trunk coupler 7 via the third port P ₃ and is used for abnormality monitoring of the dendritic optical communication network. Not only that, a part of the inspection light hν is emitted from the fourth port P ₄ and is reflected by the reflecting portion 24 to become the internal reflected light hν ′, which is incident on the fourth port P ₄ again. And then the second port P
_The light passes through ₂ and enters the light receiving portion 9.

This internally reflected light hν ′ is affected by the optical transmission path when it is transmitted through the optical transmission path between the light projecting section 8 and the bidirectional optical coupler 11 and the light receiving section 9. The optical fiber connecting the light projecting unit 8 to the bidirectional optical coupler 11 and the light receiving unit 9 may have an abnormality such as a disconnection, or the light projecting unit 8 and the bidirectional optical coupler 11 and the light receiving unit 9 may be separated from each other. When a characteristic change or the like occurs in the constituent element itself, these abnormal information appear in the data of the internal reflected light hν ′ supplied to the control unit 10. The reflection wavelength of the reflection part 24 is set to a wide wavelength range capable of reflecting all wavelength components of the inspection light hν emitted from the light projecting part 8. For example, a total reflection mirror or the like is used for the reflection part 24. To be done.

As described above, since the internal reflected light hν ′ has various information as described above, the microcomputer system built in the control unit 10 periodically
Alternatively, a self-diagnosis period for diagnosing the presence / absence of an abnormality in the monitoring device 6 itself is set before performing the original abnormality monitoring of the dendritic optical communication network, and a predetermined self-diagnosis program predetermined by firmware or the like is set. By executing and analyzing the data of the internal reflected light hν ′ output from the light receiving unit 9, the presence or absence of abnormality is determined. And
If a non-recoverable condition such as a broken optical fiber is detected in the predetermined diagnostic items, an alarm for repair (alarm display, warning lamp lighting, buzzer sound, etc.) When the emission light intensity of the light source provided in the light projecting unit 8 deviates from the normal range, feedback control is performed to correct the emission light intensity of the light source within the normal range. Perform processing such as performing automatically.

An example of such a self-diagnosis operation will be described. First, the control unit 10 causes the light projecting unit 8 to emit the inspection light hν. Whether the inspection light hν is pulsed light, continuous light, single wavelength, or light in a wide wavelength range is determined in the first to twelfth embodiments. It is set according to the function of each monitoring device 6 or determined according to the diagnostic item.

If there is no abnormality in the monitoring device 6, a part of this inspection light hν will be a part of the fourth port P4 of the bidirectional optical coupler 11.
Is transmitted to the reflection section 24 through the reflection section 24, is reflected by the reflection section 24 to become the internally reflected light hν ′, and again enters the light receiving section 9 via the bidirectional optical coupler 11. The light receiving unit 9 photoelectrically converts the internally reflected light hν ′ to generate digital data corresponding to the light intensity (or the amount of received light), or generates the spectrum data of the internally reflected light hν ′ and supplies it to the control unit 10. Will be done. Then, if the values of these data deviate from the normal range, the control unit 10 performs feedback control (drives the light source) to return the emission light intensity of the light source in the light projecting unit 8 to the normal range. Control such as controlling the power supply for On the other hand, the light projecting unit 8, the bidirectional optical coupler 11, and the light receiving unit 9
In the case where the internal reflected light hν ′ does not reach the light receiving unit 9 because an abnormality such as a disconnection has occurred in the optical fiber connecting to the control unit 10, the control unit 10 controls the above-mentioned data from the light receiving unit 9. Is analyzed to determine that an abnormality that cannot be self-recovered has occurred, and the above alarm is issued.

As described above, according to this embodiment, the self-diagnosis of the monitoring device itself is performed, so that a highly reliable monitoring system can be realized.

<Fourteenth Embodiment> Next, a fourteenth embodiment will be described with reference to FIG. This embodiment is based on the above
This is applicable to the thirteenth embodiment and relates to an optical connector for connecting each branch fiber line in the dendritic optical communication network to each subscriber terminal device, which is attached to the branch fiber line described above. The optical reflection part is built in this optical connector.

The connector plug 25 of this optical connector is
As shown in FIG. 27 (a) showing the external structure and FIG. 27 (b) showing the structure of the main part inside by partially breaking, as shown in FIG. The standard) is adopted. That is, the housing 25 at the rear end of _a, together with the optical fiber cord 25 _b from a particular branch line fiber line explained in the first to thirteenth embodiments are coupled, the optical fiber cord 2
The tip portion of the optical fiber 25 _c in 5 _b communicates with the ferrule 25 _d, further, (see FIG. 27 (d)) optical fibers in the optical fiber 25 _c 25 distal portion of the _f ferrule It extends to 25 _d of the tip 25 _e. Then, the connector plug 25, and attached to the subscriber terminal side of the connector adapter (not shown), the distal end portion 25 _e of the ferrule 25 _d, the tip end face of the optical fiber 25 _f (the input-output face of the light) The tip end surface of the optical fiber (not shown) of the connector adapter is optically connected.

Further, as a constitution peculiar to this embodiment, as shown in FIGS. 9 (b), 9 (c) and 9 (d), one end of the ferrule 25 _d (however, the portion as close to the tip portion 25 _e as possible is provided). )
In is optical fiber 25 _c intermediate portion (intermediate portion) of a predetermined length only excised and reflective portion mounting groove 25 constituting the slit-shaped space which is open to one end above _g of formed, The reflecting portion 26 is detachably fitted in the space of the reflecting portion mounting groove _25g . For example, the outer shape of the reflection part 26 shown in FIG.
It has a similar shape (substantially discoid) slightly smaller than the space shape of 5 _g . Further, the reflecting portion 26 includes the reflecting portion mounting groove 25.
A light reflection filter 26 _{a, which} is optically connected to the end faces 25 _h and 25 _i of the cut optical fiber 25 _{f in} the state of being fitted with _g , is provided in advance and covers the light reflection filter 26 _a. The same material as that of the ferrule 25 _d is applied as the supporting outer skin portion.

[0168] Light reflection filter 26 _a, for example, FIG. 3
As shown in (a) to (d), the optical fiber 25 _f has a core and a clad of the same structure, and a plurality of media having different refractive indexes from the core are integrally formed in the core at a predetermined interval. By doing so, the structure has a single reflection wavelength or a plurality of reflection wavelengths.

Then, corresponding to the various reflection wavelengths described in the first to thirteenth embodiments, a plurality of types of reflecting portions 26 each having a preset reflection wavelength are prepared and added. When the personal terminal device is connected to the dendritic optical communication network, one of the reflecting portions 26 is selected and attached to be used as a unique connector plug 25.

As described above, according to this embodiment, the parts of the connector plug 25 other than the reflection part 26 have general versatility, and therefore various reflection parts 26 having different reflection wavelengths are preliminarily arranged in series. Can be produced and managed. Further, when the subscriber terminal device is connected to the dendritic optical communication network, the reflector 26 can be selected, so that the laying work can be simplified. In addition, the monitoring device in the station can easily set the identification information (such as the information about the matching between the branch fiber line to be monitored and the reflection wavelength of the reflection part) to be registered in advance when performing the abnormality monitoring process. can do. Furthermore, since the reflecting section 26 is removable, it is extremely easy to replace it with another type of reflecting section 26 in accordance with modification of the monitoring system of the dendritic optical communication network. Further, even when it is necessary to increase the types of reflection wavelengths applied to the monitoring system as the dendritic optical communication network expands, the reflection part 26 having a new reflection wavelength is additionally manufactured to obtain the existing connector. The plug 25 can be used as it is.

These effects are merely examples, and this embodiment is applied to the monitoring system described in the first to thirteenth embodiments, so that the manufacturer that supplies parts and the maintenance management that performs maintenance management are performed. Exhibits a wide variety of excellent effects in a wide range of fields such as traders.

[0172]

As described above, according to the present invention, the reflection parts each having its own wavelength selectivity are associated with each branch filter line and connected, and the wavelength components corresponding to each reflection part are connected. For example, the presence or absence of reflected light reflected when the test light is transmitted as strobe light is measured for each wavelength, or each branch fiber is located at a different distance from the passive branch element that is the branch center. Since the branch line fiber line is monitored by measuring the scattered light reflected when a predetermined inspection light is incident on the line, it is possible to check whether the branch line fiber line is abnormal. The optical line network can be sequentially monitored by centralized monitoring at broadcasting stations and the like.

Furthermore, since a large number of branch line fiber lines can be monitored independently, it is possible to identify the branch line fiber line in which an abnormality has occurred, and it is possible to take prompt measures. Further, it is possible to realize reliable monitoring with a relatively simple system configuration, and it is possible to easily cope with a complicated optical communication network and an optical communication network which is gradually expanded. Further, by incorporating the reflecting portion in a detachable manner in the optical connector that connects the branch fiber line and the subscriber terminal, it is possible to provide a monitoring system with extremely high utilization efficiency.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a first configuration example of a monitoring system according to the present invention.

FIG. 2 is an explanatory diagram showing an arrangement example of a reflecting section attached to the monitoring system.

FIG. 3 is an explanatory diagram showing a configuration example of a reflecting section.

FIG. 4 is a block diagram showing a configuration of a monitoring device in the first embodiment.

FIG. 5 is an explanatory diagram for explaining the operation of the monitoring system.

FIG. 6 is a block diagram showing a configuration of a monitoring device according to a second embodiment.

FIG. 7 is a block diagram showing a configuration of a monitoring device according to a third embodiment.

FIG. 8 is a block diagram showing a configuration of a monitoring device according to a fourth embodiment.

FIG. 9 is a block diagram showing a configuration of a monitoring device according to a fifth embodiment.

FIG. 10 is a block diagram showing a configuration of a monitoring device according to a sixth embodiment.

FIG. 11 is a block diagram showing a configuration of a monitoring device according to a seventh embodiment.

FIG. 12 is a system configuration diagram showing a second configuration example of the monitoring system according to the present invention.

FIG. 13 is a block diagram showing the configuration of a monitoring device according to an eighth embodiment.

FIG. 14 is an explanatory diagram for explaining the operation of the eighth embodiment.

FIG. 15 is an explanatory diagram showing, as a table, a combination example of reflection wavelengths set in the reflection section used in the eighth embodiment.

FIG. 16 is an explanatory diagram for further explaining the operation of the eighth embodiment.

FIG. 17 is a block diagram showing a configuration of a monitoring device according to a ninth embodiment.

FIG. 18 is an explanatory diagram for explaining the operation of the ninth embodiment.

FIG. 19 is a system configuration diagram showing a third configuration example of the monitoring system according to the present invention.

FIG. 20 is an explanatory diagram illustrating a monitoring operation in the third configuration example illustrated in FIG. 19.

FIG. 21 is an explanatory diagram showing, as a table, a combination example of reflection wavelengths set in the reflection section used in the third configuration example shown in FIG. 19.

22 is an explanatory diagram for further explaining the monitoring operation in the third configuration example shown in FIG.

FIG. 23 is an explanatory diagram for further explaining the monitoring operation in the third configuration example shown in FIG. 19.

FIG. 24 is a block diagram showing the structure of a monitoring device according to a twelfth embodiment.

FIG. 25 is an explanatory diagram for explaining the operation of the twelfth embodiment.

FIG. 26 is a block diagram showing the structure of a monitoring device according to a thirteenth embodiment.

FIG. 27 is a structural explanatory view of an optical connector shown as a 14th embodiment.

[Explanation of symbols]

1 ... the station, 2 ... transmission device, 3 _a to 3 _c ... trunk optical fiber line, 5 _a to 5 _c ... passive branching device, 6 ... monitoring device, 7 ...
Light emitting unit, 8 ... Light receiving unit, 9 ... Light receiving unit, 10 ... Control unit, 11
... optical _{coupler, W 1 ~W N, W 11} ~W 1N, W 21 ~W 2M ... branch fiber _{line, R 1 ~R N, R 11} ~R 1N, R 21 ~
R _2M , 24, 26 ... Reflector, 25 ... Optical connector.

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H04L 11/00 340 (72) Inventor Katsuya Yamashita 1-6 Uchiyukicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation Company (72) Inventor Fumio Otsuki 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (25)

[Claims] 1. A tree branch in which an optical communication network in which a plurality of branch fiber lines are connected to a passive branch element in a dendritic manner is cascade-connected to one or more stages of upstream main optical fiber lines. In the optical communication network monitoring method, a reflection wavelength for reflecting light having a specific wavelength determined in association with each branch fiber line is set on one side of each branch fiber line. Providing a reflection portion, inspection light having a wavelength equal to any reflection wavelength set in the reflection portion, or inspection light of a wide wavelength including all reflection wavelengths set in the reflection portion, The light intensity or the amount of light received for each wavelength of the reflected light that is incident on the main line optical fiber line from the light projecting part and is reflected by the reflecting part and returns to the main line optical fiber line is measured. Set in the reflector Among the wavelengths that match the reflection wavelength, the presence or absence of a wavelength component in which the measured value of the light intensity or the amount of received light does not satisfy a predetermined reference value is analyzed, and a reflection wavelength equal to the wavelength component that does not satisfy the reference value. The method for monitoring an optical communication network is characterized in that it is determined that an abnormality has occurred in a branch fiber line provided with the reflection part of. 2. An optical communication network in which a plurality of branch fiber lines are connected to a passive branch element in a dendrite form, and a tree-like structure in which one or two or more stages are cascade-connected to an upstream main optical fiber line. In an optical communication network monitoring method for monitoring an optical communication network, a reflection wavelength for reflecting light of a specific wavelength is set so that the separation distance from the passive branching device is different on one side of each branch fiber line. Provided with a reflection part, and pulsed inspection light having a wavelength equal to the reflection wavelength set in the reflection part, or pulsed inspection light having a wide wavelength including the reflection wavelength set in the reflection part Is incident on the main optical fiber line from the light projecting unit, and measures the reflected light in the form of a pulsed light train that is reflected by the reflecting unit and returns to the main optical fiber line, from the time of incidence of the inspection light. Each pal If there is a pulsed light that is not measured at each predetermined propagation delay time up to the measurement time of the optical beam, it means that an abnormality has occurred in the branch fiber line provided with the reflection section corresponding to the pulsed light that is not measured. A method for monitoring an optical communication network, comprising: determining. 3. An optical communication network in which a plurality of branch fiber lines are connected to the passive branch element in a dendrite form is a dendritic structure in which one stage or two or more stages are cascade-connected to the upstream main optical fiber line. In an optical communication network monitoring method for monitoring an optical communication network, the separation distance from the passive branching element on one side of each of the branch line fiber lines is made different, and determined in association with each branch line fiber line. A reflection part for reflecting the light of the specific wavelength is provided, and a reflection part is set, and inspection light having a wavelength equal to any reflection wavelength set for the reflection part, or set for the reflection part Wide-wavelength inspection light including all reflection wavelengths is made incident on the trunk optical fiber line from a light projecting unit, and is reflected light in the form of a pulsed light train that is reflected by the reflecting unit and returns to the trunk optical fiber line. To measure Among the wavelengths that match the wavelength of the inspection light and the reflection wavelength set in the reflector, while analyzing the wavelength of the pulsed light in the reflected light that does not satisfy the predetermined light intensity or the amount of received light, the inspection Detecting pulsed light that is not measured at each predetermined propagation delay time from the incident time of light to the measurement time of each pulsed light, pulsed light in the reflected light that does not satisfy the predetermined light intensity or received light amount A branch fiber line provided with a reflection portion having a reflection wavelength equal to the wavelength of, or the branch fiber line provided with a reflection portion corresponding to the pulse light not measured, to determine that an abnormality has occurred, An optical communication network monitoring method characterized by. 4. An optical communication network in which a plurality of branch fiber lines are connected to a passive branch element in a dendrite form, and a tree-like structure in which one stage or two or more stages are cascade-connected to an upstream main optical fiber line. In an optical communication network monitoring method for monitoring an optical communication network, the separation distance from the passive branching element on one side of each of the branch line fiber lines is made different, and determined in association with each branch line fiber line. A reflection part for reflecting the light of the specific wavelength is provided, and a reflection part is set, and inspection light having a wavelength equal to any reflection wavelength set for the reflection part, or set for the reflection part Wide-wavelength inspection light including all reflection wavelengths is made incident on the trunk optical fiber line from a light projecting unit, and is reflected light in the form of a pulsed light train that is reflected by the reflecting unit and returns to the trunk optical fiber line. To measure The measurement result of each of the pulsed light is characterized by each propagation delay time or each of the separation distances determined in advance from the incident time of the inspection light to the measurement time of each of the pulsed light, and the wavelength of each of the pulsed light. Array processing is performed on the data group of the matrix array used as a parameter, and the data group of the matrix array and the data group of the predetermined matrix array are compared to detect the data that do not match each other, and the data that do not match each other are handled. An optical communication network monitoring method, characterized in that it is determined that an abnormality has occurred in the branch fiber line. 5. The optical communication network monitoring method according to claim 1, wherein the reflecting portion is provided in each of the branch fiber lines. 6. The light reflection filter formed by integrally forming a medium having a refractive index different from that of the core in a stripe shape in the core of each branch fiber line is used as the reflecting portion. The optical communication network monitoring method described in. 7. The method according to claim 1, wherein another passive branching element is connected to each of the branch fiber lines, and the reflecting portion is branched and connected to the other passive branching element. 2. The optical communication network monitoring method according to item 1. 8. The reflection wavelength set in each of the reflection parts is a unique single wavelength, or a plurality of kinds of wavelengths set in an exclusive relationship for each reflection part. The optical communication network monitoring method according to any one of claims 1 to 4. 9. The inspection light having a wavelength equal to any one of the reflection wavelengths set in the reflection section is generated by using a wavelength tunable light source.
The optical communication network monitoring method according to any one of 1. 10. An inspection light having a wavelength equal to any one of the reflection wavelengths set in the reflection section, and a light source for generating a wide wavelength light including all reflection wavelengths set in the reflection section. 5. A wavelength tunable filter that transmits the wide wavelength light emitted from the light source is used to generate the wide wavelength light.
The optical communication network monitoring method described in the paragraph. 11. The inspection light having a wavelength equal to any one of the reflection wavelengths set in the reflecting section is continuously made incident on the trunk optical fiber line.
The optical communication network monitoring method described in. 12. The inspection light having a wavelength equal to any one of the reflection wavelengths set in the reflector is incident on the trunk optical fiber line discretely in a time division manner. Optical communication network monitoring method. 13. The light according to claim 1, wherein the inspection light having a wide wavelength including all the reflection wavelengths set in the reflecting portion is continuously made incident on the trunk optical fiber line. Communication network monitoring method. 14. The inspection light having a wide wavelength, which includes all the reflection wavelengths set in the reflecting section, is incident on the trunk optical fiber line discretely in a time division manner. The optical communication network monitoring method described. 15. The measurement of the reflected light is performed by a light receiving unit having a photoelectric conversion element that receives the reflected light and outputs a photoelectric conversion signal, and an A / D converter that converts the photoelectric conversion signal into digital data. The optical communication network monitoring method according to any one of claims 1 to 4, which is used. 16. The spectrum analyzer according to claim 1, wherein the reflected light is measured using a spectrum analyzer that spectrally analyzes the reflected light for each wavelength and outputs digital spectral distribution data. The optical communication network monitoring method according to item 1. 17. The reflected light is measured by transmitting the reflected light through a wavelength tunable filter that changes a transmission selection wavelength, photoelectrically converting the light transmitted through the wavelength tunable filter by a photoelectric conversion element, and converting the reflected light into the photoelectric conversion element. The optical communication network monitoring method according to any one of claims 1 to 4, wherein a light receiving unit for converting a photoelectric conversion signal output from the device into digital data by an A / D converter is used. 18. The measurement of the reflected light includes interfering the reflected light with an interferometer, photoelectrically converting the interference light interfered with the interferometer with a photoelectric conversion element, and outputting the interference with the photoelectric conversion element. 5. A light receiving section for converting a photoelectric conversion signal of light into digital data by an A / D converter, and generating a spectrum distribution data based on the digital data by a Fourier transform unit is used. The optical communication network monitoring method according to any one of 1. 19. A part of the inspection light emitted from the light projecting unit according to claim 9 is a part of the inspection light according to claim 15. The other light-reflecting portion that reflects the light-receiving portion is provided, and the light-receiving portion or the light-projecting portion is based on at least one piece of wavelength, light intensity, or light-receiving amount information of the inspection light output from the light-receiving portion. A method for monitoring an optical communication network, which comprises performing a diagnosis of a unit and a feedback control of the light receiving unit or the light projecting unit. 20. A tree-like optical communication network comprising a passive branch element in which a plurality of branch fiber lines are connected in a tree-like manner, and a tree-like structure in which one or two or more stages are cascade-connected to an upstream trunk optical fiber line. In an optical communication network monitoring method for monitoring an optical communication network, in one side of each of the branch line fiber lines, each side of a different separation distance from the passive branch element, determined by associating with each branch line fiber line. Providing a reflection portion is set reflection wavelength to reflect the light of the specific wavelength, in a predetermined wavelength range including all reflection wavelengths set in the reflection portion, continuously with a predetermined wavelength change rate The inspection light whose wavelength changes is repeatedly incident on the trunk optical fiber line at an appropriate repetition period, and for each repetition period, a time point that is delayed by a predetermined phase difference from each start time point of each repetition cycle. From the above, to the wavelength tunable filter whose transmission wavelength continuously changes at the same change rate as the wavelength change rate, the pulsed light train-like reflected light reflected by the reflection section and returning to the main optical fiber line is transmitted. , Measuring the pulsed light transmitted through the wavelength tunable filter for each repetition cycle, and detecting the cycle in which the pulsed light is not detected in the repetition cycle, the phase difference set in that cycle A method for monitoring an optical communication network, characterized in that it is determined that an abnormality has occurred in a branch fiber line in which a reflection portion is provided at a separation distance corresponding to. 21. A branch comprising an optical communication network in which a plurality of branch fiber lines are connected in a tree-like manner to a passive branch element, and one or two or more stages are cascade-connected to an upstream trunk optical fiber line. Optical communication network monitoring system, in the optical communication network monitoring system, provided on one side of each of the branch fiber lines, the reflection wavelength for reflecting the light of a specific wavelength determined in association with each branch fiber line, A reflection part that is set, an inspection light having a wavelength equal to any reflection wavelength that is set in the reflection part, or a wide-wavelength inspection light that includes all reflection wavelengths that are set in the reflection part. A light projecting unit that is incident on the trunk optical fiber line; a light receiving unit that measures a light intensity or a light receiving amount for each wavelength of reflected light that is reflected by the reflecting unit and returns to the trunk optical fiber line; Wavelength of light Among the wavelengths that match the reflection wavelength set in the reflecting portion, the presence or absence of a wavelength component in which the measured value of the light intensity or the amount of received light does not satisfy a predetermined reference value is analyzed and does not satisfy the reference value. An optical communication network monitoring system, comprising: a control unit that determines that an abnormality has occurred in a branch fiber line provided with a reflection unit having a reflection wavelength equal to a wavelength component. 22. An optical communication network comprising a plurality of branch fiber lines connected to the passive branch element in a dendrite form, and a tree-like structure formed by subordinately connecting one or more stages to the upstream main optical fiber line. In an optical communication network monitoring system for monitoring an optical communication network, a reflection that is provided on one side of each of the branch fiber lines and on a side of a different separation distance from the passive branch element, and that reflects light of a specific wavelength A reflection part having a wavelength set, a pulsed inspection light having a wavelength equal to the reflection wavelength set in the reflection part, or a pulsed wide wavelength range including the reflection wavelength set in the reflection part A light projecting unit for injecting inspection light into the main optical fiber line, a light receiving unit for measuring reflected light in the form of a pulsed light train that is reflected by the reflecting unit and returns to the main optical fiber line, and the inspection light Of the above If there is unmeasured pulsed light at each predetermined propagation delay time from the time point to the measurement time point of each of the pulsed light, an abnormality occurs in the branch fiber line provided with the reflecting portion corresponding to the unmeasured pulsed light. An optical communication network monitoring system, comprising: a control unit that determines that the optical communication network is operating. 23. An optical communication network in which a plurality of branch fiber lines are connected to the passive branch element in a dendrite form is a dendritic structure in which one stage or two or more stages are cascade-connected to the upstream main optical fiber line. In an optical communication network monitoring system for monitoring an optical communication network, the optical fiber is provided on one side of each of the branch fiber lines and on a side of a different separation distance from the passive branch element, and is associated with each of the branch fiber lines. A reflection part for reflecting light having a specific wavelength determined by a reflection part, and an inspection light having a wavelength equal to any reflection wavelength set for the reflection part, or set for the reflection part. A wide-wavelength inspection light including all reflected wavelengths that is incident on the main optical fiber line from a light emitting unit, and pulsed light that is reflected by the reflecting unit and returns to the main optical fiber line. Row A light receiving unit for measuring a reflected light having a circular shape, and a wavelength that matches the wavelength of the inspection light and the reflection wavelength set in the reflecting unit, among the reflected light that does not satisfy a predetermined light intensity or a received light amount. While analyzing the wavelength of the pulsed light, detecting the pulsed light that is not measured at each predetermined propagation delay time from the incident time of the inspection light to the measurement time of each pulsed light, the predetermined light intensity or received light A branch fiber line provided with a reflection part having a reflection wavelength equal to the wavelength of the pulsed light in the reflected light that does not satisfy the amount, or a branch line fiber line provided with a reflection part corresponding to the pulse light that is not measured, An optical communication network monitoring system, comprising: a control unit that determines that an abnormality has occurred. 24. An optical communication network comprising a plurality of branch fiber lines connected to a passive branch element in a dendritic form, and a dendritic form formed by cascading one or two or more stages to an upstream main optical fiber line. In an optical communication network monitoring system for monitoring an optical communication network, the optical fiber is provided on one side of each of the branch fiber lines and on a side of a different separation distance from the passive branch element, and is associated with each of the branch fiber lines. A reflection part for reflecting light having a specific wavelength determined by a reflection part, and an inspection light having a wavelength equal to any reflection wavelength set for the reflection part, or set for the reflection part. A wide-wavelength inspection light including all reflected wavelengths is incident on the trunk optical fiber line, and a pulsed optical train is reflected by the reflector and returned to the trunk optical fiber line. light A light receiving unit for measuring the measurement result of each of the pulsed light, each propagation delay time or each of the separation distances determined in advance from the incident time of the inspection light to the measurement time of each pulsed light, and each of the above. Arrangement processing is performed on the data group of the matrix array having the wavelength of the pulsed light as a characteristic parameter, and the data groups of the matrix array and the data group of the predetermined matrix array are compared to detect data that do not match each other, An optical communication network monitoring system, comprising: a control unit that determines that an abnormality has occurred in a branch fiber line corresponding to data that does not match each other. 25. The optical fiber connector for connecting a branch fiber line and a subscriber terminal, wherein the reflecting portion is detachably incorporated into the optical connector. Optical network monitoring system.