JP2005091160A - Device for monitoring optical path - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To construct, with a good yield, an optical path monitoring system capable of monitoring an optical path exactly by simple constitution. <P>SOLUTION: Communication lights having wavelengths of λa, λb input from a light input part 4 through a main optical path connected to a communication light light source and a monitoring light light source are transmitted through the first light wavelength photomultiplexing and demultiplexing filter 5 to be branched and output by a light branch coupler 6. Monitoring lights λc<SB>1</SB>-λc<SB>8</SB>having wavelengths different each other input from the light input part 4 are reflected by the first light wavelength photomultiplexing and demultiplexing filter 5, and are photodemultiplexed by an array waveguide diffraction grating type wavelength photomultiplexing and demultiplexing instrument 8. The monitoring light in every photodemultiplexed wavelength is guided to an output part of the communication lights branched and output by the light branch coupler 6 to be photomultiplexed by the second light wavelength photomultiplexing and demultiplexing filter 7. The communication lights photomultiplexed by the second light wavelength photomultiplexing and demultiplexing filter, and the monitoring light in the every wavelength are output from light output parts 11a-11h to be input into corresponding branch optical paths. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical line monitoring device and an optical line monitoring system used in an optical communication field such as an optical passive double star (PDS) transmission system.

  Currently, in order to introduce FTTH (Fiber To The Home) at a low price, an optical PDS (Passive Double Star) system that shares one OLT (Optical Line Terminal) installed in the station with many users has been proposed. Yes.

For example, as shown in FIG. 5, the optical PDS system connects the optical splitter 28 in the middle of the optical path 22 a connected to the transmission device 10 to optically branch the optical path 22 a into the optical path 22. Furthermore, branch optical ₁ in each of the trunk optical line 22 that this is the optical branch _{(1a 1, 1a 2, ···} ) connected to a branch optical line _{1 (1a 1, 1a 2, ···} ) A user (subscriber) 24 is connected.

  In general, an optical line using an optical time domain reflector (OTDR) 2 is used for an optical subscriber line such as an optical PDS system in order to monitor an abnormality of an optical fiber or an optical communication device as an optical line medium. A monitoring system has been introduced. In this system, the monitoring light from the OTDR 2 is input to the respective trunk optical lines 22 via the fiber selector (FS) 25 and the optical coupler 18.

An optical line monitoring device 3 having the function of an optical splitter is provided between each main optical line 22 and the branched optical line 1 (1a ₁ , 1a ₂ ,...). The device 3 transmits the monitoring light from the OTDR 2 and the communication light propagating from the transmission device 10 through the optical splitter 28 and the optical coupler 18 through the optical trunk line 22 to the respective branched optical lines 1 (1a ₁ , 1a ₁ , 1a ₂ ,... The monitoring light is configured to be reflected at the terminal end side of the branch optical line 1 (1a ₁ , 1a ₂ ,...) And return to the OTDR 2. By measuring the monitoring light, abnormality of the optical line is detected. The communication light is received by the ONU (optical subscriber line terminating device) 20 of the user 24.

As an example of the optical line monitoring system, there is an optical line monitoring system of a branch optical line length management system. The system branch optical _{1 (1a 1, 1a 2,} ···) is set to the length of different lengths for each, end of the branch optical _{1 (1a 1, 1a 2,} ···) The distance between the monitoring light reflecting mechanism such as a filter provided in the OTDR 2 and the OTDR _{2 is set} to a different length for each of the branched optical lines 1 (1a ₁ , 1a ₂ ,.

The branch optical _{1 (1a 1, 1a 2,} ···) after laying, the output to branch optical ₁ from _{OTDR2 (1a 1, 1a 2,} ···) monitoring light returned at the end position of the Are measured when the branch optical line 1 (1a ₁ , 1a ₂ ,...) Is normal, and this measurement data and the return light data of the monitoring light measured in the same manner when an abnormality such as a failure occurs. In this way, the faulty branch optical line 1 is identified (for example, see Non-Patent Document 1).

  Another example of the optical line monitoring system is a terminal reflection wavelength assignment type optical line monitoring system. In this system, the wavelength of the terminal reflection of the branch optical line 1 is assigned to each branch optical line, monitored by the variable wavelength OTDR2 or the like, and the failure line is specified by measuring the increase or decrease in the amount of reflected light (for example, Non-patent document 2).

Furthermore, a wavelength routing type optical line monitoring system has been proposed as yet another example of the optical line monitoring system. For example, as shown in FIG. 6, the proposed system includes a wavelength λc _{1 to} λc _n on the trunk optical line 22, for example, communication light having a wavelength λa and a plurality of wavelengths different from each other (for example, n is an integer of 2 or more) ) Propagates and enters the optical line monitoring device 3, and the optical line monitoring device 3 assigns the monitoring light wavelength to each branch optical line 1 (1a ₁ , 1a ₂ ,...). (For example, see Non-Patent Document 3).

  In this wavelength routing type optical line monitoring system, a variable wavelength OTDR may be used.

  The optical line monitoring device 3 applied to this wavelength routing system must have a function of branching communication light and a function of demultiplexing the monitoring light. For example, an arrayed waveguide diffraction as shown in FIG. It is formed by an applied product of a lattice.

Optical component shown in FIG. 7 demultiplexes the monitor light of the communication light wavelength λc ₁ ~λc _n wavelength λa by the optical filter 30, the communication light from the communication light input section 31 of the circuit of the arrayed waveguide grating type And the monitoring light is input from the monitoring light input unit 32. The communication light passes through the filter 37 that transmits the communication light and reflects the monitoring light, enters the slab waveguide 33 through the communication light input waveguide 42, spreads in the slab waveguide 33, and is transmitted to each light output guide. The light enters the waveguide 36 and exits from its output end.

  On the other hand, the monitoring light enters the slab waveguide 33 through the monitoring light input waveguide 43, spreads by the diffraction effect of the slab waveguide 33, enters the array waveguide 34, and is reflected by the filter 37. The light propagates back and forth through the waveguide 34, passes through the slab waveguide 33 again, is demultiplexed for each wavelength, and is emitted from a different light output waveguide 36 for each wavelength.

Yamamoto et al., “1.6 μm band fault isolation test technology for branching optical lines”, 1994 IEICE Autumn Meeting B-846 Ito et al., "Study on Fault Monitoring Method on PDS Line" 1996 IEICE General Conference B-1073 Tanaka et al., "Individual loss distribution measurement of branched optical line by test wavelength allocation method", 1996 IEEJ Electronics, Information and Systems Conference A-9-4

  However, each of the proposed optical line monitoring systems has the following problems. For example, the optical line monitoring system of the branch optical line length management system needs to design the lengths of the branched optical lines to be different from each other when laying the optical line, and the design work is troublesome. was there. Moreover, when this system was applied to monitor the branch optical line, it was only possible to know which branch optical line had an abnormality such as a failure, and the abnormal position could not be specified.

  In addition, the optical system for monitoring the optical line of the terminal reflection wavelength allocation method can know which branch optical line has an abnormality when a failure such as a disconnection occurs, but there is no reflection and an abnormality that increases only the loss. When this occurs, there is a problem that it is impossible to specify at which position the abnormality has occurred.

  Further, although the wavelength routing type optical line monitoring system can know what kind of abnormality has occurred in which branch optical line 1 at the time of failure, the circuit configuration as shown in FIG. The manufacturing process for integrating an arrayed waveguide grating type circuit that also functions as a coupler on one chip becomes complicated, and it is difficult to improve the yield.

  The present invention has been made to solve the above-described conventional problems, and its purpose is to be able to accurately monitor what kind of abnormality has occurred in which branch optical line when a failure occurs. An object of the present invention is to provide an optical line monitoring device with a high yield capable of forming an optical line monitoring system.

  In order to achieve the above object, the present invention has the following configuration as means for solving the problems. That is, the optical line monitoring device according to the first aspect of the present invention is the monitoring light having a plurality of wavelengths different from each other inputted from the optical input unit, and inputted from the optical input unit having a wavelength different from the monitoring light. A first optical wavelength multiplexing / demultiplexing filter that demultiplexes the communication light, and an optical branching coupler that is provided on the communication optical demultiplexing side of the first optical wavelength multiplexing / demultiplexing filter and branches the communication light into a plurality of , Provided on the monitoring light demultiplexing side of the first optical wavelength multiplexing / demultiplexing filter, further demultiplexing the monitoring light for each wavelength, and each of the demultiplexed wavelengths corresponding to each of the optical branching couplers. An arrayed waveguide grating type wavelength multiplexer / demultiplexer guided to the output side, and communication light provided on the output side of the optical branching coupler and branched and output by the optical branching coupler, and the arrayed waveguide grating type wavelength multiplexer / demultiplexer. Wavelength guided from the demultiplexer side to the output side of each optical branching coupler A second optical wavelength multiplexing / demultiplexing filter that multiplexes the monitoring light and the plurality of lights that respectively output the communication light and the monitoring light for each wavelength combined by the second optical wavelength multiplexing filter A configuration having an output unit serves as means for solving the problem.

  Further, in the optical line monitoring device according to the second invention, in addition to the first invention, the communication light has light having at least one wavelength of 1.31 μm, 1.49 μm, and 1.55 μm, and the monitoring light is It is a means to solve the problem with a configuration with light having a plurality of different wavelengths of 1.60 μm to 1.70 μm.

  The optical line monitoring device according to a third aspect of the present invention has a problem that, in addition to the first and second aspects of the invention, the monitoring light is light having a plurality of different wavelengths from 1.625 μm to 1.675 μm. As a means to solve the problem.

  The optical line monitoring device according to a fourth aspect of the invention is that in addition to any one of the first to third aspects of the invention, the monitoring light is light having a plurality of different wavelengths from 1.64 μm to 1.66 μm. As a means to solve the problem.

  The optical line monitoring device according to a fifth aspect of the present invention is a means for solving the problem by adding four or eight optical output units of the optical branching coupler in addition to any one of the first to fourth aspects of the invention. Yes.

  According to a sixth aspect of the present invention, there is provided the optical line monitoring device according to any one of the first to fifth aspects, wherein the optical branching coupler is formed by a planar waveguide circuit formed by forming an optical waveguide circuit on a substrate. The planar waveguide circuit is provided with a first optical wavelength multiplexing / demultiplexing filter and a second optical wavelength multiplexing / demultiplexing filter as means for solving the problem.

  In addition to any one of the first to sixth inventions, the optical line monitoring device of the seventh invention is a plane in which an arrayed waveguide grating type wavelength multiplexer / demultiplexer is formed on the same substrate as the optical branching coupler. It is a means for solving the problem by being formed by a waveguide circuit.

  An optical line monitoring device according to an eighth aspect of the present invention is the optical line monitoring device according to any one of the first to seventh aspects, wherein at least one of the first and second optical wavelength multiplexing / demultiplexing filters is a dielectric multilayer filter. The dielectric multilayer filter formed is a means for solving the problem by reflecting the monitoring light and transmitting the communication light.

  According to a ninth aspect of the present invention, there is provided the optical line monitoring device according to any one of the first to eighth aspects, wherein the first optical wavelength multiplexing / demultiplexing filter and the second optical wavelength multiplexing / demultiplexing filter are formed by the same filter. It is a means to solve the problem with having formed.

  In addition to any one of the first to ninth inventions, the optical line monitoring device of the tenth invention is a transmission wavelength region of each of the monitoring light demultiplexed by the arrayed waveguide grating type wavelength multiplexer / demultiplexer. Is set as 1.0 nm or more as means for solving the problem.

  According to the optical line monitoring device of the present invention, the demultiplexing of the communication light and the monitoring light by the first optical wavelength multiplexing / demultiplexing filter, the communication optical branching by the optical branching coupler, the array waveguide diffraction grating type wavelength multiplexing, Monitoring light demultiplexing by a demultiplexer is performed, and the monitoring light for each wavelength output after the demultiplexing and the branched communication light are multiplexed by a second optical wavelength multiplexing / demultiplexing filter, thereby simplifying With such a configuration, it is possible to satisfactorily perform branching of communication light and demultiplexing of monitoring light, and a device with a high yield can be obtained.

  The optical line monitoring device according to the present invention is applied to a wavelength routing type optical line monitoring system to accurately detect which abnormality has occurred in which branch optical line at the time of failure. Possible optical line monitoring system can be constructed.

  In the optical line monitoring device according to the present invention, the communication light includes light having at least one wavelength of 1.31 μm, 1.49 μm, and 1.55 μm, and the monitoring light is 1.6 μm or more and less than 1.7 μm. According to the configuration composed of light of multiple different wavelengths, the optical line monitoring that can accurately detect the presence or absence of the fault and the location of the fault as described above, with the specifications of the current optical line monitoring system as it is System can be constructed at low cost.

  Further, in the optical line monitoring device of the present invention, according to the configuration in which the monitoring light is light having a plurality of different wavelengths of 1.625 μm or more and less than 1.675 μm, in the existing optical line monitoring system, the branched optical line With the monitoring light reflection mechanism such as the filter provided on the terminal side or the user side as it is, the optical line monitoring system that can accurately detect the presence of the fault and the location of the fault as described above can be constructed at low cost It can be.

  Furthermore, in the optical line monitoring device of the present invention, according to the configuration in which the number of light output portions of the light branching coupler is 4 or 8, the light output portion is formed corresponding to the number of light output portions of the light branching coupler, An optical line monitoring system can be constructed at a low cost while keeping the number of branched optical lines applied to the current optical line monitoring system.

  Further, in the optical line monitoring device of the present invention, the optical branching coupler is formed by a planar waveguide circuit formed by forming an optical waveguide circuit on a substrate, and the first optical wavelength multiplexing / demultiplexing is formed on the planar waveguide circuit. According to the configuration in which the filter and the second optical wavelength multiplexing / demultiplexing filter are provided, it is possible to further reduce the size and cost of the optical line monitoring device.

  Furthermore, in the optical line monitoring device of the present invention, the arrayed waveguide grating type wavelength multiplexer / demultiplexer is formed by a planar waveguide circuit formed on the same substrate as the optical branching coupler. The device can be further reduced in size and cost.

  Furthermore, in the optical line monitoring device of the present invention, a dielectric multilayer filter is applied to at least one of the first and second optical wavelength multiplexing / demultiplexing filters to reflect the monitoring light and transmit the communication light. Accordingly, the optical wavelength multiplexing / demultiplexing filter can be suitably configured.

  Furthermore, in the optical line monitoring device of the present invention, according to the configuration in which the first optical wavelength multiplexing / demultiplexing filter and the second optical wavelength multiplexing / demultiplexing filter are formed by the same filter, the number of parts of the optical line monitoring device is increased. It is possible to further reduce the cost.

  Furthermore, in the optical line monitoring device of the present invention, according to the configuration in which each transmission wavelength region of the monitoring light demultiplexed by the arrayed waveguide diffraction grating type wavelength multiplexer / demultiplexer is 1.0 nm or more, the application of the device Since the demultiplexing of the monitoring light can be performed accurately without providing a temperature adjustment mechanism within the temperature range, the cost of the optical line monitoring device can be further reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the present embodiment, the same reference numerals are assigned to the same names as those in the conventional example, and the duplicate description is omitted or simplified.

FIG. 1 shows a first embodiment of an optical line monitoring device according to the present invention. FIG. 2 shows an example of an optical line monitoring system using the optical line monitoring device of this embodiment. The optical line monitoring device 3 of the present embodiment is applied to, for example, a wavelength routing type optical line monitoring system as shown in FIG. 2, and includes an optical main line 22 and branch optical lines 1 (1a _{1 to} 1a ₈ ). Between the two.

As shown in FIG. 1, the optical line monitoring device 3 according to the present embodiment includes one optical input unit 4 and eight optical output units 11 (11a to 11h), and is provided on the optical input unit 4 side. reflects monitor light having a wavelength λc ₁ ~λc ₈ a plurality of mutually different input from the light input portion 4 (here eight), and the wavelength λa that is different from the wavelength of the monitoring light, the λb A first optical wavelength multiplexing / demultiplexing filter 5 is provided which transmits the communication light input from the optical input unit 4 and demultiplexes the monitoring light and the communication light.

In the present embodiment, the communication light wavelength λa is 1.31 μm, and the communication light wavelength λb is 1.55 μm. The monitoring light wavelength is a preset wavelength of 1.60 μm or more and less than 1.70 μm, and is light having a plurality of different wavelengths λc ₁ , λc ₂ ,... Λc ₈ of 1.625 μm or more and 1.675 μm or less.

The monitoring light wavelengths applied in this embodiment are λc ₁ = 1.6575 μm, λc ₂ = 1.6550 μm, λc ₃ = 1.6525 μm, λc ₄ = 1.6500 μm, λc ₅ = 1.6475 μm, λc ₆ = 1.6450 μm, λc ₇ = 1.6425 μm, and λc ₈ = 1.6400 μm.

  On the communication light transmission side of the first optical wavelength multiplexing / demultiplexing filter 5, an optical branching coupler 6 that branches the communication light into a plurality (here, eight) is provided, and the first optical wavelength multiplexing / demultiplexing filter 5 An arrayed waveguide diffraction grating type wavelength multiplexer / demultiplexer 8 is provided on the monitoring light reflecting side 5.

  The arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 includes one optical input waveguide 12, a first slab waveguide 13 connected to the output side of the optical input waveguide 12, and the first The arrayed waveguide 14 connected to the output side of the slab waveguide 13, the second slab waveguide 15 connected to the output side of the arrayed waveguide 14, and the output side of the second slab waveguide 15 And a plurality of optical output waveguides 16 arranged in parallel.

  The arrayed waveguide 14 is formed by a plurality of channel waveguides 14 a arranged in parallel, and the arrayed waveguide 14 propagates light derived from the first slab waveguide 13. The channel waveguides 14a are formed to have different lengths, and the lengths of the adjacent channel waveguides 14a are different from each other by ΔL.

  In general, a large number of channel waveguides 14a are provided, for example, 100, but in FIG. 1, the number of channel waveguides 14a is simply shown for the sake of simplicity. In the present embodiment, the number of light output portions of the arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 (number of light output waveguides 16) is equal to the light output portions 9 (9a to 9h) of the light branching coupler 6. ) Equal to the number of).

  The arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 has a function of demultiplexing light of a plurality of wavelengths for each wavelength by the circuit configuration as described above, and is applied to the present embodiment. Each transmission wavelength region of the multiplexing / demultiplexing wavelength of the waveguide diffraction grating type wavelength multiplexer / demultiplexer 8 is set to 1.0 nm or more.

In this embodiment, the arrayed waveguide grating type wavelength multiplexer / demultiplexer ₈ demultiplexes the monitoring light for each wavelength (λc ₁ , λc ₂ ,... Λc ₈ ), and each demultiplexed wavelength λc. ₁ , λc ₂ ,... Λc ₈ are guided to the corresponding individual output unit 9 (9 a to 9 h) of the eight output units 9 of the optical branching coupler 6.

A second optical wavelength multiplexing / demultiplexing filter 7 is provided on the output section 9a-9h side of the optical branching coupler 6, and the second optical wavelength multiplexing / demultiplexing filter 7 is branched by the optical branching coupler 6. Wavelengths λa, λb of the output communication light and wavelengths λc ₁ , λc ₂ , guided from the arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 side to the output units 9a to 9h of the optical branching coupler 6, respectively. -It has a function of multiplexing the monitoring light for each λc ₈ .

Similarly to the first optical wavelength multiplexing / demultiplexing filter 5, the second optical wavelength multiplexing / demultiplexing filter 7 transmits the communication optical wavelengths λa, λb and monitors the optical wavelengths λc ₁ , λc ₂ ,. ₈ is formed by a filter which reflects the second optical wavelength division multiplexing filter 7, the wavelength selective transmission reflection function, the communication wavelength λa that is output from the second optical wavelength division multiplexing filter 7 , Λb, and reflects the monitoring light wavelengths λc ₁ , λc ₂ ,... Λc ₈ guided from the arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 to combine the communication light and the monitoring light for each wavelength. To wave.

  The communication light combined by the second optical wavelength combining filter 7 and the monitoring light for each wavelength are output from the light output units 11a to 11h, respectively.

  In the present embodiment, the form of forming the optical branching coupler 6 and the arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 is not particularly limited, but in this embodiment, the planar waveguide formed on the same substrate is used. The first optical wavelength multiplexing / demultiplexing filter 5 is provided on the input side of the optical branching coupler 6 on the planar waveguide circuit, and the second optical wavelength coupler 6 is provided on the output side of the optical branching coupler 6. An optical wavelength multiplexing / demultiplexing filter 7 is provided. Further, the first and second optical wavelength multiplexing / demultiplexing filters are not particularly limited, but are formed by, for example, a dielectric multilayer filter in the present embodiment.

The optical line monitoring device 3 according to the present embodiment is configured as described above. For example, in the conventional conventional system configuration as shown in FIG. 2, the device according to the present embodiment is installed in the conventional splitter installation portion. 3 is connected to the optical input unit 4 of the optical line monitoring device 3 via the optical main lines 22 and 22a, the transmission device 10 as the communication light source and the OTDR 2 as the monitoring light source. A branching optical line 1 (1a ₁ , 1a ₂ ,...) That is an optical line corresponding to each output unit of the monitoring device 3 can be connected to form a wavelength routing type optical line monitoring system.

  In the optical line monitoring system shown in FIG. 2 in which the optical line monitoring device 3 of the present embodiment is applied to the conventional system configuration, the light source of the OTDR 2 uses the monitoring light having a plurality of different wavelengths for each wavelength. The OTDR 2 is connected to the fiber selector 25 via the monitoring light multiplexing / demultiplexing array waveguide diffraction grating 26. The monitoring optical multiplexing / demultiplexing array waveguide diffraction grating 26 has the same wavelength multiplexing / demultiplexing function as the arrayed waveguide grating type wavelength multiplexing / demultiplexing device 8 applied to the optical line monitoring device 3 of this embodiment. ing.

The optical line monitoring system shown in FIG. 2 in which the optical line monitoring device 3 according to the present embodiment is applied to the conventional system configuration includes monitoring lights having different wavelengths respectively output from the plurality of output units 27 of the OTDR 2. The signals are multiplexed by the arrayed waveguide diffraction grating 26 for monitoring light multiplexing / demultiplexing, and input to the optical main line 22 via the fiber selector 25 and the optical coupler 18 interposed in each optical main line 22. The communication light output from the light is split by the optical splitter 28 and input to the plurality of optical main lines 22. Then, the communication light having the wavelengths λa and λb and the monitoring light having a plurality of wavelengths λc ₁ , λc ₂ ,... Λc ₈ input to each optical main line 22 are the optical line monitoring of the present embodiment. Is input to the optical input unit 4 of the device 3.

  Then, as shown in FIG. 1, the communication light passes through the first optical wavelength multiplexing / demultiplexing filter 5, is branched by the optical branching coupler 6, and is output from each of the optical output units 9a to 9h. Each branched communication light is individually transmitted to the light output units 11a to 11h through the wavelength multiplexing / demultiplexing filter 7.

  On the other hand, the monitoring light is reflected by the first optical wavelength multiplexing / demultiplexing filter 5, and then demultiplexed for each wavelength by the arrayed waveguide diffraction grating type wavelength multiplexing / demultiplexing unit 8. It is guided to the corresponding individual light output units 9a to 9h. Each of these monitoring lights is reflected by the second optical wavelength multiplexing / demultiplexing filter 7 and is combined with each of the branched communication lights that have been transmitted through the second optical wavelength multiplexing / demultiplexing filter 7. It propagates to the output units 11a to 11h.

Then, from the light output portion 11a of the optical line monitoring device 3, the wavelength [lambda] a, [lambda] b, the light of [lambda] c ₁ is output from the light output section 11b, as such wavelengths [lambda] a, [lambda] b, the light of [lambda] c ₂ is output The monitoring light and the communication light of the corresponding wavelength are output from the respective light output units 11a to 11h. As described above, the optical line monitoring device 3 according to the present embodiment performs the branching of the communication light and the demultiplexing of the monitoring light, and outputs the combined light.

In the optical line monitoring system shown in FIG. 2 in which the optical line monitoring device 3 is applied to the conventional system configuration, the communication light output from each of the optical output units 11a to 11h of the optical line monitoring device 3 and the monitoring for each wavelength. The light is input to the corresponding branched optical lines 1a _{1 to} 1a ₈ . Then, the communication light propagated through branch optical _1a 1 to 1A ₈ user 24 side is received by the ONU (optical network unit) 20 of the user 24.

Further, the monitoring light for each wavelength is reflected by a monitoring light reflecting mechanism (not shown) provided on the near side of the communication light receiving unit of the ONU 20 and returns to the branched optical lines 1a _{1 to} 1a ₈ for each wavelength. Then, the light is incident on each of the light output units 11 a to 11 h of the optical line monitoring device 3.

The monitoring light for each wavelength that has returned to the respective optical output units 11a to 11h of the optical line monitoring device 3 propagates through the optical line monitoring device 3 through the reverse path to the array waveguide diffraction grating type. The signals are multiplexed by the wavelength multiplexer / demultiplexer ₈ and output from the optical input unit 4 as the return light of the monitoring light having a plurality of wavelengths λc ₁ , λc ₂ ,... Λc ₈ .

  This monitoring light is further demultiplexed for each wavelength by the monitoring light multiplexing / demultiplexing array waveguide diffraction grating 26 via the optical coupler 18 and the fiber selector 25, and returns to each output unit 27 of the OTDR2. Detects the return of the monitoring light for each wavelength, and detects the presence / absence of abnormality of each branch optical line 1 and the position of occurrence of abnormality by a known line abnormality (failure) detection method using OTDR.

  As described above, the optical line monitoring device 3 according to the present embodiment can branch the communication light and demultiplex the monitoring light, so that it can be applied to a wavelength routing type optical line monitoring system. In addition, it is possible to construct an optical line monitoring system that can detect what kind of abnormality has occurred in which branch optical line 1 when a failure occurs.

  Further, the optical line monitoring device 3 of this embodiment is formed by a planar optical waveguide circuit in which the optical branching coupler 6 and the arrayed waveguide diffraction grating type wavelength multiplexer / demultiplexer 8 are formed on the same substrate. Since it is a simple configuration in which the first and second optical wavelength multiplexing / demultiplexing filters 5 and 7 are provided in the planar optical waveguide circuit, it can be easily manufactured with high yield, and a small and inexpensive device can be realized. The difficulty of miniaturization by the configuration shown in FIG. 7 can be solved.

Further, the optical line monitoring device 3 of this embodiment example has communication light wavelengths of 1.31 μm and 1.55 μm, a monitoring light wavelength of 1.6 μm band, and the number of light output units 11 a to 11 h is eight. Since it can be connected to the _eight branched optical lines 1 (1a _{1 to} 1a ₈ ), it can be applied to the current optical line monitoring system, so that the optical communication can be performed using the light of the currently applied wavelength. Optical line monitoring can be performed satisfactorily.

  Furthermore, since the optical line monitoring device 3 of the present embodiment example uses a plurality of different wavelengths of light having a monitoring light wavelength of 1.64 μm or more and 1.66 μm or less, when applied to an optical line monitoring system, A system can be constructed by applying a member to which a monitoring light reflection mechanism (such as a filter for monitoring light reflection) provided on the user 24 side of the system is currently applied, and an inexpensive system can be constructed.

  Furthermore, the optical line monitoring device 3 according to the present embodiment has a transmission wavelength range of 1.0 nm or more of the optical multiplexing / demultiplexing wavelength of the arrayed waveguide diffraction grating type wavelength multiplexer / demultiplexer 8, so that the temperature dependency is 0. Since the .01 nm / ° C. arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 can be used without adjusting the temperature in the range of −20 ° C. to 80 ° C., for example, it is possible to further reduce the size and the cost. Can do.

  As shown in FIG. 3, the optical line monitoring device 3 of the present embodiment is an optical line having a configuration in which the monitoring light multiplexing / demultiplexing array waveguide diffraction grating 26 provided immediately after the OTDR 2 is omitted in FIG. It can also be applied to a monitoring system. 3 does not have the array waveguide diffraction grating 26 for monitoring light multiplexing / demultiplexing, for example, a plurality of different light sources such as a supercontinuum light source such as a supercontinuum light source provided in the OTDR 2 and a plurality of different wavelength light sources. Monitoring light having a wavelength is output and input to the fiber selector 25, and then input to the trunk optical line 22 via the optical coupler 18.

  The monitoring light propagating through the trunk optical line 22 is input to the optical line monitoring device 3 and is demultiplexed. After entering the corresponding branch optical line 1 and reflected on the terminal side, the optical line monitoring device. Return to 3 and combine. Thereafter, since the monitoring light having a plurality of wavelengths returned through the backbone optical line 22 is input to the OTDR 2 while having a plurality of wavelengths via the fiber selector 25, the light is analyzed and analyzed for each wavelength on the OTDR 2 side. The presence / absence of a road abnormality and an abnormal part are detected.

  For the analysis for each wavelength, the above-described arrayed waveguide grating type wavelength multiplexer / demultiplexer can be used. In this case, the arrayed waveguide grating type wavelength multiplexer / demultiplexer is installed on the monitoring light input side of the OTDR2, and the light receiving element of the OTDR2 is provided on each output side of the arrayed waveguide grating type wavelength multiplexer / demultiplexer. A method of selecting the connection between the light receiving element of OTDR2 and the output of the arrayed waveguide grating type wavelength multiplexer / demultiplexer using an optical switch or the like is used.

  In FIG. 3, it is also possible to use a wavelength-tunable OTDR. In this case, by controlling the light source wavelength of the OTDR to any one of λc1 to λc8, it is possible to arbitrarily monitor a desired branch optical line.

  Next, a second embodiment of the optical line monitoring device according to the present invention shown in FIG. 4 will be described. In addition, in the optical line monitoring device 3 of the second embodiment, the description of the components configured in the same manner as the first embodiment is omitted or simplified.

  The optical line monitoring device 3 of the second embodiment differs from the optical line monitoring device 3 of the first embodiment in that the optical input unit 4 and the optical output units 11a to 11h are connected to the optical line monitoring device. 3, the first optical wavelength multiplexing / demultiplexing filter 5 and the second optical wavelength multiplexing / demultiplexing filter 7 are configured by the same filter.

  The second embodiment is configured as described above, and the second embodiment can also achieve the same effect by the same operation as the first embodiment.

  In the second embodiment, the first optical wavelength multiplexing / demultiplexing filter 5 and the second optical wavelength multiplexing / demultiplexing filter 7 are configured by the same filter, so the number of parts of the optical line monitoring device 3 is reduced. The price can be further reduced by reducing it.

  In addition, this invention is not limited to the said embodiment example, Various aspects can be taken. For example, the communication light wavelength and the monitoring light wavelength are not necessarily the wavelengths applied in the above-described embodiments. For example, the communication light wavelength is at least one wavelength of 1.31 μm, 1.49 μm, and 1.55 μm. These are set as appropriate in accordance with the system specifications.

  In each of the above embodiments, the number of the optical output units 9 of the optical branching coupler 6 is eight, but the number of the optical output units 9 of the optical branching coupler 6 is a number other than eight (for example, 4, 16, etc. as appropriate). The number of the optical output waveguides 16 of the arrayed waveguide diffraction grating type wavelength multiplexer / demultiplexer 8 and the number of the optical output units of the optical line monitoring device 3 may be set corresponding to this number. If the number of light output units of the optical line monitoring device 3 is set to 4 or 8, and connected to the corresponding branch optical line 1, it can be easily applied to a conventionally used optical line monitoring system.

  Each transmission wavelength region of the monitoring light demultiplexed by the arrayed waveguide grating type wavelength multiplexer / demultiplexer 8 is set to 1.0 nm or more, but the transmission wavelength region of the demultiplexed monitoring light is not particularly limited, It is set appropriately. However, if the transmission wavelength region of the demultiplexed monitoring light is set to an appropriate value of 1.0 nm or more, the optical line monitoring device 3 can be used without adjusting the temperature, for example, within a temperature range of about 100 ° C. It is possible to further reduce the price and reduce the price, which is preferable.

  Further, the monitoring light is preferably 1.625 μm or more and 1.675 μm or less, and in this case, since it matches the transmission band determined by the international standard, the versatility spreads, and the optical line monitoring device 3 can be used in various systems. Since it can be used, the price can be further reduced.

It is a principal part block diagram which shows 1st Example of the device for optical line monitoring which concerns on this invention. It is a principal part block diagram which shows an example of the system for optical line monitoring which applied the device for optical line monitoring which concerns on this invention to the conventional system structure. It is a principal part block diagram which shows another example of the optical line monitoring system which applied the device for optical line monitoring which concerns on this invention to the conventional system structure. It is a principal part block diagram which shows 2nd Example of the optical line monitoring device which concerns on this invention. It is a schematic diagram for demonstrating the conventional system for optical line monitoring. It is a schematic diagram for description of a wavelength routing type optical line monitoring system. It is explanatory drawing of the optical device applied to the wavelength routing system optical line monitoring system proposed conventionally.

Explanation of symbols

1, 1a ₁ to 1A _n-branch optical network 2 OTDR
DESCRIPTION OF SYMBOLS 3 Optical line monitoring device 4 Optical input part 5 1st optical wavelength multiplexing / demultiplexing filter 6 Optical branching coupler 7 2nd optical wavelength multiplexing / demultiplexing filter 8 Array waveguide diffraction grating type wavelength multiplexing / demultiplexing 9, 9a- 9h Output unit 10 Transmission device 11a to 11h Optical output unit

Claims (10)

A first optical wavelength combination for demultiplexing the monitoring light having a plurality of different wavelengths input from the optical input unit and the communication light having a wavelength different from that of the monitoring light and input from the optical input unit. A demultiplexing filter, an optical branching coupler that is provided on the communication light demultiplexing side of the first optical wavelength multiplexing / demultiplexing filter and branches the communication light into a plurality of signals, and monitoring light of the first optical wavelength multiplexing / demultiplexing filter Provided on the demultiplexing side, the monitoring light is further demultiplexed for each wavelength, and the light of each demultiplexing wavelength is guided to the corresponding individual output unit side of the optical branching coupler. A communication device provided on the output unit side of the optical branching coupler and branched and output by the optical branching coupler, and each output unit side of the optical branching coupler from the arrayed waveguide grating type wavelength multiplexer / demultiplexer side A second optical wavelength combination for combining the monitoring light for each wavelength guided to Optical line monitoring device, characterized in that it comprises a wave filters, and a plurality of light output portions by the second optical wavelength multiplexing filter multiplexed communication light and for each wavelength of monitor light outputted respectively. The communication light has at least one wavelength of 1.31 μm, 1.49 μm, and 1.55 μm, and the monitoring light is composed of light having a plurality of different wavelengths that are not less than 1.60 μm and less than 1.70 μm. The optical line monitoring device according to claim 1. The optical line monitoring device according to claim 1, wherein the monitoring light is light having a plurality of different wavelengths of 1.625 μm to 1.675 μm. The optical line monitoring device according to any one of claims 1 to 3, wherein the monitoring light is light having a plurality of different wavelengths of 1.64 µm to 1.66 µm. 5. The optical line monitoring device according to claim 1, wherein the number of optical output units of the optical branching coupler is four or eight. The optical branching coupler is formed by a planar waveguide circuit formed by forming an optical waveguide circuit on a substrate, and a first optical wavelength multiplexing / demultiplexing filter and a second optical wavelength multiplexing / demultiplexing filter are provided on the planar waveguide circuit. 6. The optical line monitoring device according to claim 1, wherein the optical line monitoring device is provided. 7. The optical line according to claim 1, wherein the arrayed waveguide grating type wavelength multiplexer / demultiplexer is formed by a planar waveguide circuit formed on the same substrate as the optical branching coupler. Monitoring device. At least one of the first and second optical wavelength multiplexing / demultiplexing filters is formed by a dielectric multilayer filter, and the dielectric multilayer filter reflects the monitoring light and transmits the communication light. The optical line monitoring device according to any one of claims 1 to 7, wherein the device is an optical line monitoring device. 9. The optical line monitoring device according to claim 1, wherein the first optical wavelength multiplexing / demultiplexing filter and the second optical wavelength multiplexing / demultiplexing filter are formed of the same filter. . 10. The transmission wavelength region of each of the monitoring lights to be demultiplexed by the arrayed waveguide grating type wavelength multiplexer / demultiplexer is set to 1.0 nm or more, according to claim 1. Optical line monitoring device.

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