JP6533606B2 - Judgment device - Google Patents

Description

  The present invention relates to a technology for determining the presence or absence of connection of an optical network termination unit (ONU: Optical Network Unit) arranged at a subscriber side.

  With the increase of subscribers to the optical access network, in a newly built apartment house or the like, an optical cable may be drawn into the house beforehand regardless of whether it is a member of the optical access network or not. If a non-subscriber wants to join, it is possible to receive service by connecting the ONU to the optical cable that has already been pulled in without having to carry in the optical cable.

  When inspecting and constructing optical cables for optical access networks, in order to prevent accidental accidents such as cutting the optical cables in use, investigate whether the optical cables pulled into the home are actually used or not There is a need. Generally, whether the optical cable is actually used or not is determined based on whether or not the ONU is connected to the end of the optical cable.

  For example, Patent Document 1 discloses a detection apparatus and a detection method for confirming the presence or absence of an ONU by detecting upstream light transmitted by the ONU in a predetermined cycle in an optical cable from the drawdown closure to the ONU. Have been described.

Patent No. 5637914 gazette

  However, although the detection apparatus and detection method of Patent Document 1 can detect without stopping the communication, it has not been possible to detect an ONU which is disposed on the subscriber side and whose power is off. .

  For example, conventionally, when it is not possible to determine whether a state in which an ONU whose power is off is connected is connected and a state in which only a connector is connected (or a disconnected state) without visual confirmation. was there. For this reason, it may take time to check visually. In addition, it was considered that if the work is proceeded without visual confirmation, erroneous cutting may occur.

  In view of the above circumstances, the present invention has an object to provide a technology capable of confirming the presence or absence of connection of an ONU which is disposed on the subscriber side and whose power is off without visually confirming the ONU. .

The determination apparatus according to the present invention is a determination apparatus for determining the presence or absence of an optical line terminal connected to the end of an optical cable, wherein the optical line terminal outputs light in a first wavelength band to perform upstream communication And a filter for introducing light of a second wavelength band into the optical line termination device, and outputting light of the first wavelength band to one end of the optical cable for first reflection A light input / output unit that receives light and outputs light of the second wavelength band to one end of the optical cable to receive second reflected light; and a first based on the first reflected light the reflection characteristics were obtained with the input light information acquisition unit for acquiring second reflection characteristic on the basis of the second reflected light, wherein the first reflection characteristic and the second reflection characteristic and the light by comparing the And a determination unit that determines whether the line termination apparatus is connected. It features.

  In the above determination apparatus, the determination unit is configured to set a plurality of two-dimensional planes on the basis of a predetermined reference, with a reflection characteristic of light in the first wavelength band and a reflection characteristic of light in the second wavelength band as axes. Divide into areas, specify the area to which the point indicated by the first reflection characteristic and the second reflection characteristic on the two-dimensional plane belongs, and determine the state of the end of the optical cable based on the area It is characterized by

  According to the present invention, it is possible to confirm the presence / absence of connection of an ONU which is disposed on the subscriber side and whose power is off without visually confirming the ONU.

FIG. 1 is a system configuration diagram showing a configuration of an optical communication system according to an embodiment of the present invention. It is a functional block diagram showing the functional composition of the judging device concerning one embodiment of the present invention. It is a figure showing an example of the threshold value of the judgment concerning one embodiment of the present invention. It is a figure explaining the mechanism in which the difference of a reflective attenuation amount generate | occur | produces between the light of the wavelength of a 1.31 micrometer band, and the light of a 1.49 micrometer band or a 1.55 micrometer band in ONU. It is a figure showing an example of the management table which concerns on one Embodiment of this invention. It is a figure showing an example of the determination result table which concerns on one Embodiment of this invention. It is a figure showing an example of the procedure of the judgment processing concerning one embodiment of the present invention. It is a determination area | region diagram showing an example of the area | region of the determination which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the determination processing which concerns on one Embodiment of this invention.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a system configuration diagram showing the configuration of an optical communication system 1 according to an embodiment of the present invention.

  The optical communication system 1 shown in FIG. 1 is a branch that stores an image distribution OLT 11 and an IP communication OLT 12, an optical cable 13, and an optical branching element 22 which are specific examples of a station-side optical line terminal (OLT: Optical Line Terminal). The optical cable 71 is provided with a wiring closure 21, a pulling-down closure 31, an optical cable 41, an optical line terminal (ONU) 51, a judging device 61, and connectors 72 and 73. The OLT is an optical line termination device installed on the telecommunications carrier side. The image distribution OLT 11 transmits downstream light of a wavelength of 1.55 micrometer (μm) band, and the OLT 12 for IP communication transmits downstream light of a wavelength of 1.49 μm band.

  The optical cable 13 connects the OLT and the optical branching element 22, and the optical cable 41 connects the optical branching element 22 and the ONU 51 installed in the subscriber's house (hereinafter referred to as "subscriber's house").

  The light emitted from the OLT to the ONU 51 travels through the optical cable 13 and reaches the optical branching element 22. The light branching element 22 branches the light transmitted through the optical cable 13 into a plurality of optical cables 41.

  Each light branched by the light branching element 22 travels through the optical cable 41 and reaches the ONU 51 of the subscriber home.

  In the optical communication system 1, the direction from the OLT to the ONU 51 is referred to as "downward direction", and the direction from the ONU 51 to the OLT is referred to as "upward direction". Further, light flowing in the downstream direction is referred to as “downstream light”, and light flowing in the upstream direction is referred to as “upstream light”.

  The ONU 51 transmits a signal using burst light (hereinafter referred to as “burst light”) in the upstream direction at a predetermined cycle. Therefore, upstream light is generated in the optical cable 41 to which the ONU 51 is connected at a predetermined cycle. In addition, upstream light is also generated at a predetermined cycle in the optical cable 41 connected to the ONU 51 and the optical cable 13 connected via the light branching element 22.

  The optical branching element 22 stored in the branch wiring closure 21 is installed in the wiring column, and connected to the optical cable 13 pulled up from the ground to the air along the lifting column. The branch wiring closure 21 branches downstream light transmitted from the video distribution OLT 11 and the IP communication OLT 12 to the plurality of optical cables 41. The drawdown closure 31 is installed in the drawdown column, and connects the optical cable 41 branched by the light branching element 22 to the ONU 51 of the subscriber's home. Thus, the drawdown closure 31 causes the light branched by the light branching element 22 to flow to the ONU 51 of the subscriber's home.

  The ONU 51 sends upstream light of a wavelength of 1.31 μm band. The upstream light emitted from the ONU 51 is pulled down via the optical cable 41 to reach the closure 31, and further reaches the light branching element 22 of the branch wiring closure 21 via the optical cable 41, and for video distribution via the optical cable 13. The OLT 11 and the IP communication OLT 12 are reached.

  The determination device 61 is a device that detects the presence of the ONU 51. The determination device 61 is connected to the optical cable 41 to determine whether the ONU 51 is connected to the end of the optical cable 41 in the downstream direction. The determination device 61 is connected to the optical cable 41 between the light branching element 22 and the subscriber side.

  FIG. 2 is a functional block diagram showing a functional configuration of the determination device 61 according to an embodiment of the present invention.

  The determination device 61 includes a key input unit 111, a light input / output unit 112, a display unit 113, a storage unit 114, a control unit 115, and a connector 116. The control unit 115 includes a light output control unit 131, an input light information acquisition unit 132, a determination unit 133, and a display control unit 134.

  Further, FIG. 2 illustrates an example of the state of connection with the outside when the determination device 61 determines whether the ONU 51 is connected. That is, FIG. 2 shows the optical cable 71 having the connectors 72 and 73, the closure 211, the connector 212, the optical cable 221, and the connection destination 231 on the subscriber side, in addition to the determination device 61.

  Here, the closure 211 corresponds to the branch wiring closure 21 or the draw-down closure 31 shown in FIG. The optical cable 221 corresponds to the optical cable 41 shown in FIG. The connection destination 231 corresponds to a subscriber's home. In this embodiment, as the connection state of the optical cable 41 at the connection destination 231, a state in which the ONU 51 whose power is on is connected, a state where the ONU 51 whose power is off (power off) is connected, There is a state in which the ONU 51 is not connected (in a state in which only the connector is connected or in a disconnected state). In this embodiment, in the case where the closure 211 is either the branch wiring closure 21 or the draw-down closure 31, the judging device 61 is connected to the optical cable 221 branched to each subscriber's house.

  The closure 211 comprises a connector 212 connected with the optical cable 221. The connector 116 of the determination device 61 and the connector 212 of the optical cable 221 are connected using an optical cable 71 having connectors 72 and 73 at both ends. Specifically, the connector 72 provided at one end of the optical cable 71 is connected to the connector 116 of the determination device 61, and the connector 73 provided at the other end of the optical cable 71 is connected to the connector 212 of the optical cable 221. Here, the standards of the connectors 72 and 116 connected to each other are the same, and the standards of the connectors 73 and 212 connected to each other are the same. As an example, the standard of the connectors 72 and 116 may be an SC connector, and the standard of the connectors 73 and 212 may be a FAS connector. The connectors (the connectors 72 and 116 or the connectors 73 and 212) connected to each other are configured such that one is inserted into the other.

  In the present embodiment, the optical cable 71 having the connectors 72 and 73 is configured separately from the determination device 61, but as another configuration example, these may be integrated.

  If the standards of the connector 116 of the determination device 61 and the connector 212 of the optical cable 221 are the same, these connectors 116 and 212 may be directly connected.

  The determination device 61 includes, for example, a central processing unit (CPU), a memory, an auxiliary storage device, and the like connected by a bus, and executes a program of the determination process. The determination device 61 functions as an apparatus including the key input unit 111, the light input / output unit 112, the display unit 113, the storage unit 114, and the control unit 115 by execution of the program. Note that all or part of the functions of the determination device 61 may be realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA).

  The key input unit 111 has one or more keys, and inputs the contents of the operation performed on the keys. The key may include, for example, a key for switching on and off the power of the determination device 61, and a key for giving the determination device 61 an instruction to execute a program of the determination process. In the present embodiment, an operation of the key input unit 111 is performed by a person who carries the determination device 61 (hereinafter referred to as “worker”).

  The light input / output unit 112 outputs light to the outside through the connector 116, and inputs light from the outside through the connector 116. In the present embodiment, the light input / output unit 112 inputs and outputs burst light having a wavelength of 1.31 μm and burst light having a wavelength of 1.55 μm. The burst light may be generated using, for example, pulsed light (pulsed light).

  The display unit 113 is configured using an image display device such as a liquid crystal display or an organic EL (Electro Luminescence) display, and displays information on a screen.

  The storage unit 114 is configured using a random access memory (RAM), a read only memory (ROM), and the like, and stores information.

  The control unit 115 performs various processes and controls. When the content of the operation is input by the key input unit 111, the control unit 115 performs processing and control based thereon.

  The light output control unit 131 controls the light output to the outside by the light input / output unit 112. The input light information acquisition unit 132 acquires information on light input to the light input / output unit 112 from the outside by performing predetermined calculations or the like.

  Here, in the present embodiment, the burst light output from the light input / output unit 112 to the outside is reflected by the outside and returned from the light input / output unit 112. The input light information acquisition unit 132 is configured to reflect the level (power) of the burst light output from the light input / output unit 112 with respect to the burst light having each wavelength (1.31 μm, 1.55 μm) Based on the level (power) of the burst light input to the input / output unit 112, the reflection attenuation amount (information of the value) is acquired.

  In general, the return loss [dB] by a predetermined object is represented by {−10 × log (power of light reflected from object / power of input light to object)}.

  Further, the input light information acquisition unit 132 acquires the amount of reflection attenuation (information of the value) at the external far end (at the connection destination 231 in the example of FIG. 2). As a method of determining the reflected light at the far end, for example, the technology of OTDR (Optical Time Domain Reflectometers) may be used. Specifically, when there are a plurality of connectors (not shown) from the light input / output unit 112 to the far end, reflected light from each connector is mixed, but using burst light enables each connector to It is possible to determine the reflected light from the far end in a timely manner by shifting the reflection timing of

  The determination unit 133 determines, based on the information acquired by the input light information acquisition unit 132, the presence or absence of the connection of the ONU 51.

  The display control unit 134 controls the display of the information by the display unit 113, and causes the display unit 113 to display, for example, information on the result of the determination by the determination unit 133.

  An example of the determination method performed by the determination unit 133 will be described with reference to FIG.

  FIG. 3 is a diagram illustrating an example of a determination threshold according to an embodiment of the present invention. An XY orthogonal coordinate system is shown in FIG. The X axis (horizontal axis) shows the return loss (absolute value) of light of 1.31 μm, and the Y axis (vertical axis) shows the return loss (absolute value) of light of 1.55 μm. Further, assuming that a and b are real numbers, a straight line 311 (Y = aX + b) representing a threshold is shown.

  The determination unit 133 sets the reflection attenuation amount (absolute value) of the 1.31 μm burst light acquired by the input light information acquisition unit 132 as X ′, and the 1.55 μm burst light acquired by the input light information acquisition unit 132 Assuming that Y '> aX' + b when Y 'is the reflection attenuation amount (absolute value) of Y', it is determined that the ONU 51 is connected at the connection destination 231, and Y '≦ aX' + b. It is determined that the ONU 51 is not connected at the connection destination 231.

  The determination method in the present embodiment is based on the reflection characteristic (reflection characteristic in the optical module) of the ONU 51 that outputs light of 1.31 μm. Specifically, when light having a wavelength of 1.31 μm and light having a wavelength of 1.55 μm that are reflected within the optical module of ONU 51 are compared, light having a wavelength of 1.31 μm tends to be more reflected. Light having a wavelength of 1.55 μm tends to be more transparent. The method of determination in the present embodiment performs determination based on the difference between the amount of reflection of light and the amount of transmission due to such difference in wavelength.

  Here, a mechanism will be described in which a difference in return loss occurs between light of a wavelength of 1.31 μm band and light of a 1.49 μm band or 1.55 μm band in the ONU 51 of power-off.

  FIG. 4 is a view showing the configuration of an optical module provided in the ONU 51. As shown in FIG. The optical module of the ONU 51 includes a light emitting element 511 which outputs upstream light of a wavelength of 1.31 μm, a light receiving element 512 which receives downstream light of a wavelength of 1.49 μm, a wavelength of 1.49 μm and 1.55 μm The multi / demultiplexing filter 513 that reflects light in the direction of the light receiving element 512 and the wavelength selection filter 514 that transmits light of a 1.49 μm band wavelength are provided.

  Most of the light of the wavelength of 1.31 μm band incident on the ONU 51 is reflected in the direction of the optical cable 41 by the multiplexing / demultiplexing filter 513, and is received by the determination device 61.

  The 1.49 μm band light incident on the ONU 51 is reflected by the multiplexing / demultiplexing filter 513 in the direction of the light receiving element 512, passes through the inside of the optical module, and passes through the wavelength selection filter 514. Thereafter, light of wavelength 1.49 μm is reflected by the light receiving element 512, transmitted through the wavelength selection filter 514, passed through the optical module, reflected by the multiplexing / demultiplexing filter 513, and reflected toward the optical cable 41. , And received by the determination device 61.

  The light of wavelength of 1.55 μm band incident on the ONU 51 is reflected in the direction of the light receiving element 512 by the multiplexing / demultiplexing filter 513, passes through the inside of the optical module, is reflected by the wavelength selection filter 514, and is again inside the optical module As a result, the light is reflected by the combining / splitting filter 513 and received by the determination device 61.

  As described above, light of wavelengths in the 1.49 μm band and 1.55 μm band passes through the inside of the optical module, so the amount of return loss measured by the determination device 61 is large compared to light of the wavelength in the 1.31 μm band. Become. The light of the 1.49 μm band wavelength is also transmitted through the wavelength selection filter 514, so that the return loss is further increased.

  The light having two different wavelengths used as the test light by the determination device 61 is preferably light of a wavelength of 1.31 μm and light of a wavelength of 1.49 μm in consideration of the difference in return loss. However, considering the cost of the determination device 61, a module that outputs light in the 1.49 μm band is more expensive, so light in the 1.31 μm band and light in the 1.55 μm band are desirable. . Even if light of a wavelength of 1.31 μm band and light of a wavelength of 1.55 μm band are used as the two test lights of the determination device 61, the presence or absence of the ONU 51 can be detected by comparing the reflection attenuation amount.

  In FIG. 3, as an example, when the return loss (absolute value) of 1.31 μm burst light is P1 and the return loss (absolute value) of 1.55 μm burst light is Q1, the acquisition result 331 is The determination unit 133 determines that the ONU 51 is connected at the connection destination 231, which corresponds to a coordinate value. As another example, when the return loss (absolute value) of 1.31 μm burst light is P2 and the return loss (absolute value) of 1.55 μm burst light is Q2, the coordinate value of the acquisition result 332 The determination unit 133 determines that the ONU 51 is not connected at the connection destination 231.

  As described above, the determination unit 133 determines the presence or absence of the connection of the ONU 51 based on the difference between the reflection attenuation amounts (unit of [dB]) for light having two different wavelengths.

  As a tendency, when the ONU 51 is not connected to the connection destination 231 and only the connector is connected, the return loss is small for both 1.31 μm and 1.55 μm, and these return loss The difference in quantity is also small. Further, in the state where the ONU 51 is not connected to the connection destination 231 and in the disconnected state, the amount of return loss is large for both 1.31 μm and 1.55 μm, and the difference between the return loss amounts is small. When the ONU 51 is connected to the connection destination 231, the return loss at 1.31 μm is small, the return loss at 1.55 μm is large, and the difference between the return losses is large.

  Here, various values may be used as a and b in Y = aX + b, and may be set empirically based on, for example, the results of measuring a large number of samples in advance. a and b may be, for example, fixed values. For example, a value close to 1 or 1 may be used as a. As an example, when the variance of the measurement points (X ′, Y ′) of the sample is large, it may be considered that the determination accuracy may be better if a value larger than 1 is used. For example, 0 may be used as b, but for example, when a positive value is used, the state in which the ONU 51 is not connected to the connection destination 231 (the state in which only the connector is connected or disconnection is In some cases, it may be possible to make it easier to distinguish from the state. In the present embodiment, a threshold represented by a linear function (straight line 311) is used, but as another configuration example, a threshold represented by a second or higher function may be used.

Example 1
Referring to FIGS. 5 to 7, an example of an operation in which the worker confirms the presence or absence of the connection of the ONU 51 using the determination device 61 will be shown. FIG. 5 is a diagram showing an example of the management table 411 according to the embodiment of the present invention. FIG. 6 is a diagram showing an example of the determination result table 421 according to the embodiment of the present invention. FIG. 7 is a diagram illustrating an example of the procedure of the determination process according to an embodiment of the present invention.

  In this example, a case where a worker carries the determination device 61 and works on the branch wiring closure 21 above the wiring column shown in FIG. 1 is shown.

  The management table 411 illustrated in FIG. 5 stores a managed state of each branch line of the light branching element 22 that branches one line into eight lines (branch lines). In the example of FIG. 5, the management table 411 stores the number (wire number) of each branch line and the status in association with each other. In the example of FIG. 5, the status of the branch line whose wire number is 1 or 2 is the current use (status currently being used), and the status of the branch line whose wire number is 3 is reserved (will be used in the future Therefore, the status of branch lines with line numbers 4 to 8 is empty (empty status). The content of the management table 411 is managed by, for example, a manager of the optical communication system 1 using a database (DB) or the like, and notified to the worker by an arbitrary medium such as a document or an electronic screen. The management table 411 may be managed using, for example, a computer.

  First, the worker determines the actual situation of each branch line of the light branching element 22. In the present embodiment, the worker does not remove the connection between the optical branching element 22 and the optical cable 41 for each of the branching lines to which the optical cable 41 is connected in the optical branching element 22, and the power is supplied to the optical cable 41. It is detected (judged) whether or not the ONU 51 of which is turned on is connected. As a method of this detection, any method may be used, and for example, the method of detection described in Patent Document 1 may be used.

  The determination result table 421 shown in FIG. 6 stores, for each branch line of the light branching element 22, the determined actual situation. In the example of FIG. 6, the determination result table 421 associates and stores the number (wire number) of each branch line and the determined condition (determination result). In the example of FIG. 6, the determination result of the branch line whose wire number is 1 is detection (the state in which the ONU 51 whose power is turned on is connected), and the branch line whose wire number is 2 to 8 The judgment result of is not detected (the state where the ONU 51 whose power is turned on is not connected). It is preferable not to disconnect the connection between the optical branching element 22 and the optical cable 41 for the branching line to which the ONU 51 whose power is turned on is connected.

  Further, in the example of FIG. 6, there is a possibility that the ONU 51 whose power is off is connected to the branch lines whose line numbers are 2 to 8. In particular, for the line number 2 whose status is currently in use in the management table 411 and the line number 3 whose status is reserved, the power is turned off more than the line numbers 4 to 8 where the status is empty. It is considered that there is a high possibility that one ONU 51 is connected.

  Thus, the connection status of the branch line of each wire number may be different between the data being managed and the actual determination result (local facility status).

  The determination result table 421 may be managed by a worker or the like as, for example, a document or electronic data, or may not be generated as a document or electronic data if it is grasped by the worker .

  Next, the worker disconnects the connection between the light branching element 22 and the optical cable 41 for each of one or more of the wire numbers 2 to 8 and uses the determination device 61 according to the present embodiment, It is determined whether the ONU 51 is connected.

  In the present embodiment, the branch line not detected is determined after it is determined whether or not the connection of the ONU 51 whose power is on without first disconnecting the connection between the optical branching element 22 and the optical cable 41 is determined. The presence or absence of the connection of the ONU 51 (in particular, the presence or absence of the connection of the ONU 51 whose power is off) is determined using the determination device 61 according to the present embodiment. The presence or absence of the connection of the ONU 51 (the presence or absence of the connection of the ONU 51 whose power is on or off) may be determined using the determination device 61 according to the present embodiment.

  An example of the procedure of the determination process performed by the determination device 61 according to the present embodiment will be described with reference to FIG. 7. In the present embodiment, the case of making a determination on the branch line of the wire No. 3 is shown, but the same applies to the branch lines of other line numbers.

(Step S1)
The worker connects the determination device 61 and the optical cable 41 to be determined. In the example of FIG. 2, the worker is a branch line of the connector 212 to which the optical cable 221 (corresponding to the optical cable 41 shown in FIG. 1) to be determined is connected and the light branching element 22 (in this example, the wire number 3) Disconnect the connection with Then, the worker connects the connector 212 and the connector 116 of the determination device 61 via the optical cable 71 having the connectors 72 and 73.

(Step S2)
Next, the worker operates the key input unit 111 of the determination device 61 to start the program of the determination process in the determination device 61. The power supply of the determination device 61 may be turned on before the connector 116 of the determination device 61 is connected to the connector 212 or after the connector 116 of the determination device 61 is connected to the connector 212. May be When the determination processing program is activated, the determination device 61 executes a predetermined determination processing. The determination process is automatically performed by the determination device 61 after being activated.

(Step S3)
First, under the control of the light output control unit 131, the determination device 61 outputs burst light having a wavelength of 1.31 μm at a predetermined level (power) from the light input / output unit 112 to the connection destination 231.

(Step S4)
The burst light having a wavelength of 1.31 μm output to the connection destination 231 is reflected at the connection destination 231, and the reflected light returns to the determination device 61. The determination device 61 detects (acquires) the level (power) of the burst light (reflected light) having a wavelength of 1.31 μm input to the light input / output unit 112 by the input light information acquisition unit 132, and the reflection attenuation thereof Measure (acquire) the amount.

(Step S5)
The determination device 61 sets a threshold for burst light having a wavelength of 1.55 μm based on the return loss obtained for the burst light having a wavelength of 1.31 μm by the determination unit 133. The threshold shown in FIG. 3 is used as the threshold.

(Step S6)
Next, the determination device 61 outputs burst light having a wavelength of 1.55 μm at a predetermined level (power) from the light input / output unit 112 to the connection destination 231 under the control of the light output control unit 131.

(Step S7)
The burst light having a wavelength of 1.55 μm output to the connection destination 231 is reflected at the connection destination 231, and the reflected light returns to the determination device 61. The determination device 61 detects (acquires) the level (power) of the burst light (reflected light) having a wavelength of 1.55 μm input to the light input / output unit 112 by the input light information acquisition unit 132, and the reflection attenuation thereof Measure (acquire) the amount.

  (Step S8) Next, based on the threshold set by the determination unit 133 and the reflection attenuation amount obtained for the burst light having a wavelength of 1.55 μm, the determination device 61 uses ONU 51 as the connection destination 231. It is determined whether or not it is connected. Here, in the case where it is determined by the determination device 61 that the ONU 51 is connected to the connection destination 231, the connection destination 231 is initially determined by another method (for example, the method described in Patent Document 1). If it is detected (determined) that the ONU 51 whose power is on is not connected, it is understood that the ONU 51 whose power is off is connected. Note that only the ONU 51 whose power is on or the ONU 51 whose power is off is connected only because the determining device 61 determines that the ONU 51 is connected to the connection destination 231. It is understood.

(Step S9)
Under the control of the display control unit 134, the determination device 61 displays information on the determination result on the screen of the display unit 113. Arbitrary information may be used as the information related to the determination result. For example, information indicating that the ONU 51 is connected to the connection destination 231 or information indicating that the ONU 51 is not connected to the connection destination 231 Etc. are used. Also, the information to be displayed may be, for example, information on characters, information on figures, or information on a combination of these. The determination device 61 may output information of sound (voice) related to the determination result. The worker can grasp the determination result based on the information output from the determination device 61. In the present embodiment, after such a display is performed, the determination process in the determination device 61 ends.

  (Step S10) The operator disconnects the determination device 61 from the optical cable 221 (corresponding to the optical cable 41 shown in FIG. 1) to be determined after the determination process by the determination device 61 is completed. In addition, the worker again connects the connector 212 to which the optical cable 221 is connected to the branch line of the light branch element 22 (in this example, the branch line of the line No. 3), as needed, to obtain the original connection. Return to state.

  In this example, the worker carries the determination device 61 and performs the work on the branch wiring closure 21 above the wiring pillar shown in FIG. 1, but as another example, The same applies to the case where a worker carries the determination device 61 and works on the drawdown closure 31 above the drawdown column shown in FIG.

  As described above, in the determination device 61 according to the present embodiment, the presence or absence of connection of the terminal environment (ONU 51) in the subscriber's home based on the difference between the reflection characteristics (for example, the reflection attenuation amount) of light having two different wavelengths. Can be determined. In the determination apparatus 61 according to the present embodiment, the ONU 51 is connected not only when the ONU 51 whose power is on is connected but also when the ONU 51 whose power is off is connected. Can be determined. In the determination device 61 according to the present embodiment, for example, even when the ONU 51 whose power is off due to the breaker of the subscriber's house being turned off when the subscriber goes out for a long time is connected It can be determined that the ONU 51 is connected. Thereby, the worker can grasp the presence or absence of the connection of the ONU 51 at the number line whose use status is unknown even when the worker is above the pillar (for example, the wiring pillar or the drop pillar) in the opening construction etc. Can be carried out smoothly. As described above, in the determination device 61 according to the present embodiment, it is possible to confirm the presence or absence of the ONU 51 which is disposed on the subscriber side and the power is off without visually confirming the ONU 51.

  Here, in the example of FIG. 7, the determination device 61 sets the threshold based on the return loss of the burst light having a wavelength of 1.31 μm, and then sets the return loss of the burst light having a wavelength of 1.55 μm. Although the determination is made based on the above, as another configuration example, after setting the threshold based on the return loss of the burst light having a wavelength of 1.55 μm, the return loss of the burst light having a wavelength of 1.31 μm is used. The determination may be made based on. Further, as another configuration example, the determination device 61 does not set the threshold value, and is based on the reflection attenuation amount of burst light having a wavelength of 1.31 μm and the reflection attenuation amount of burst light having a wavelength of 1.55 μm. The determination may be made.

  Further, in the example of FIG. 7, the determination device 61 performs the determination by acquiring the reflection attenuation amount as the light reflection characteristic, but if it is possible to perform substantially the same determination as another configuration example, The determination may be made by acquiring a value other than the return loss. For example, the determination device 61 may obtain the light reception level of the reflected light as the light reflection characteristic and perform the determination using the light reception level.

  Further, in the example of FIG. 7, the determination device 61 outputs and inputs burst light having a wavelength of 1.31 μm and burst light having a wavelength of 1.55 μm at different timings, but as another configuration example, Of the burst light may be output and input at the same timing (here, a timing when some or all overlap).

  Further, as another configuration example, the determination unit 61 causes the determination unit 133 to reflect the reflection characteristics (for example, reflection) of one or both of burst light having a wavelength of 1.31 μm and burst light having a wavelength of 1.55 μm. Based on the amount of attenuation), the distance to the far end (end) may be specified (detected), and the specified distance may be used for determination. As an example, the determination device 61 may adjust the threshold based on the identified distance by the determination unit 133. In this case, for example, the correspondence between the distance and the adjustment method of the threshold is stored in advance in the storage unit 114 of the determination device 61.

  Further, in the present embodiment, the determination device 61 includes burst light having a wavelength of 1.31 μm corresponding to the wavelength of upstream light transmitted by the ONU 51 and burst light having a wavelength of 1.55 μm corresponding to the wavelength of downstream light. The determination may be performed using burst light having a wavelength of 1.31 μm and burst light having any other wavelength as another configuration example. As an example, the determination device 61 may perform the determination using burst light having a wavelength of 1.31 μm and burst light having a wavelength of 1.49 μm. In addition, if the determination device 61 can determine, the determination device 61 may perform the determination using burst light having any other two wavelengths. In general, the larger the difference in wavelength, the larger the difference in reflection characteristics, which is preferable.

  Further, in the present embodiment, the determination device 61 performs determination using burst light, but as another configuration example, determination may be performed using light other than burst light, for example, using continuous light The determination may be made.

  Further, in the present embodiment, the determination device 61 performs determination using light having two different wavelengths, but as another configuration example, determination is performed using light having three or more different wavelengths. Also in this case, the principle of determination is similar, and can be determined based on, for example, the reflection characteristics of light having any two different wavelengths.

(Example 2)
Next, in addition to the presence / absence of connection of the ONU 51, the determination unit 133 determines whether the connector is connected to the optical cable 41 or the fiber of the optical cable 41 is disconnected. explain.

  When only the connector is connected to the end of the optical cable 41, the return loss is small for light of any wavelength of 1.31 μm, 1.49 μm, and 1.55 μm. In the disconnected state where the end of the optical cable 41 is cut, the light is irregularly reflected at the end face of the fiber, so the return loss is large for light of any wavelength of 1.31 μm, 1.49 μm, and 1.55 μm. . In either case, the difference in return loss between the light at the 1.31 μm wavelength and the light at the 1.49 μm or 1.55 μm wavelength is small.

  In the second embodiment, as shown in FIG. 8, light having two different wavelengths measured by dividing a two-dimensional plane having axes of each of reflection attenuation amounts of light having two different wavelengths into a plurality of regions. The presence or absence of ONU and the state of the end of the optical cable are determined based on the area in which the point where the return loss of the optical fiber is plotted is present.

  In the judgment area diagram of FIG. 8, the connector identification area is set at the lower left of the 1.31 μm light at 25 dB or less and the reflection attenuation of 1.55 μm light at 23 dB or less. There is an ONU identification area on the upper right where the difference between the return loss and the return loss of light at 1.55 μm is 5 dB or more, and the connector identification area and the presence of ONU reflection of light at 1.31 μm outside the identification area The fiber cutting identification area was set in the area where the attenuation amount and the reflection attenuation amount of the light of 1.55 μm are almost the same. The ratio of the return loss of 1.55 μm light to the return loss of light of 1.31 μm is 10 dB or less, the return loss of 1.55 μm light is 10 dB or less, or the return loss of 1.31 μm light. An area in which is less than 6/11 is considered as a detection error. In addition, the threshold value which divided the area | region in FIG. 8 is an example. Each region may be set so that the state of the end of the optical cable can be determined based on the reflection characteristics of light having two different wavelengths.

  The operation of the worker using the determination device 61 to confirm the presence or absence of the connection of the ONU 51 and the state of the end of the optical cable 41 will be described. Below, it demonstrates with reference to FIGS. 5-7 suitably.

  The worker determines, for each of the branch lines of the light branch element 22, without disconnecting the connection between the light branch element 22 and the branch line, whether or not the ONU 51 whose power is on is connected. Here, as in the determination result table 421 of FIG. 6, it is detected that the ONU 51 whose power is turned on is connected to the branch line with the line number 1 and the branch lines with the line numbers 2 to 8 are detected. It is assumed that the determination result is undetected.

  The branch lines of line numbers 2 to 8 to which the ONU 51 whose power is turned on is not connected are not in communication, and therefore, the connection with the optical branching element 22 may be disconnected. For example, the optical cable 41 of the line No. 3 is removed from the light branching element 22 with the line No. 3 reserved in the management table 411 of FIG. 5 as the determination target, and the following steps are performed using the determination device 61.

  Similar to steps S1 to S7 in FIG. 7, the worker connects the determination device 61 and the optical cable 41 to be determined, operates the determination device 61, and the reflection attenuation amount of burst light having a wavelength of 1.31 μm. And the return loss of the burst light having a wavelength of 1.55 μm.

  In step S8 of FIG. 7, the determination unit 133 determines the state of the end of the optical cable based on the measured return loss amount.

  FIG. 9 is a flowchart illustrating the flow of the determination process of the determination unit 133 of the second embodiment. The determination process of FIG. 9 corresponds to step S8 of FIG.

(Step S81)
The determination unit 133 determines whether the distance to the end is 10 m or more. The distance to the end can be detected based on the return loss of one or both of the burst lights having a wavelength of 1.31 μm or 1.55 μm.

(Step S82)
If the distance to the end is less than 10 m, the determination unit 133 sets a “less than 10 m” flag, and proceeds to step S83. If the distance to the end is less than 10 m, the situation of the end can not be determined accurately, so it is clearly specified that it is less than 10 m, and the determination result described later is displayed as reference information.

(Steps S83 and S84)
When the reflection attenuation amount of burst light having a wavelength of 1.55 μm is 10 dB or more and less than 23 dB and the reflection attenuation amount of burst light having a wavelength of 1.31 μm is 10 dB or more and less than 25 dB, It is determined that there is no ONU (connector connection).

(Steps S85 and S86)
The determination unit 133 is a burst light having a wavelength of 1.51 μm or 1.31 μm and a reflection attenuation of burst light of less than 10 dB, or 1.51 μm and a reflection attenuation of 1.31 μm. If it is less than a value obtained by multiplying 6/11 by the return loss amount, it is judged as a detection error.

  In addition to the condition of the return loss, the determination unit 133 can not measure the return loss of at least one of the two wavelengths, and when the detection distance to the end has a difference of 2 m or more depending on the wavelength, Determined as a detection error.

(Steps S87 and S88)
The determination unit 133 has a value obtained by subtracting the reflection attenuation amount of burst light having a wavelength of 1.31 μm from the reflection attenuation amount of burst light having a wavelength of 1.55 μm is 5 dB or more, and has a wavelength of 1.31 μm. If the return loss of the burst light is less than 40 dB, it is determined that there is an ONU.

(Step S89)
If the determination unit 133 does not meet any of the conditions of steps S83, S85, and S87, the determination unit 133 determines that there is no ONU (fiber disconnection).

  In step S9 of FIG. 7, the display control unit 134 displays information on the determination result by the determination unit 133 on the screen of the display unit 113. Specifically, based on the determination results of steps S81, S83, S85, and S87, the display control unit 134 has an ONU at the center of the screen of the display unit 113, no ONU (connector connection), no ONU (fiber disconnection), Display detection errors and information less than 10m. When the less than 10 m flag is set, the display control unit 134 additionally displays the reference information of the presence of ONU, no ONU (connector connection), no ONU (fiber disconnection), and detection error on the screen of the display unit 113 .

  The display control unit 134 may display the reflection attenuation amount and the total reflection amount of the burst light having the wavelengths of 1.31 μm and 1.55 μm on the screen of the display unit 113. The display control unit 134 may display on the screen of the display unit 113 the distance to the end detected based on the reflection attenuation amount of the burst light having a wavelength of 1.55 μm.

  Similar to step S10 in FIG. 7, the worker disconnects the connection between the determination device 61 and the optical cable 41 to be determined after the determination process by the determination device 61 is completed. The worker repeats the processes of steps S1 to S9 for other branch lines, if necessary.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Optical communication system, 11 ... OLT for image delivery, 12 ... OLT for IP communication, 13, 41, 71, 221 ... Optical cable, 21 ... Branch wiring closure, 22 ... Optical branching element, 31 ... Drop closure, 51 ... ONU 61 determination device 72 73 116 116 212 connector 111 key input unit 112 light input / output unit 113 display unit 114 storage unit 115 control unit 131 light output control Unit 132 Input light information acquisition unit 133 Determination unit 134 Display control unit 211 Closure 231 Connection destination 311 Straight line 331, 332 Acquisition result 411 Management table 421 Determination result table

Claims (2)

A determination device for determining the presence or absence of an optical line termination device connected to the end of an optical cable, comprising:
The optical line termination apparatus outputs light in a first wavelength band to perform upstream communication, and includes a filter for introducing light in a second wavelength band into the optical line termination apparatus.
The light of the first wavelength band is output to one end of the optical cable to receive the first reflected light, and the light of the second wavelength band is output to one end of the optical cable to form a second A light input / output unit that receives reflected light;
And on the basis of the first reflected light and obtaining a first reflection characteristic, the input light information acquisition unit for acquiring second reflection characteristic on the basis of the second reflected light,
A determination unit that determines whether the optical line termination device is connected by comparing the first reflection characteristic and the second reflection characteristic;
The determination apparatus characterized by having.   The determination unit divides a two-dimensional plane on the basis of a reflection characteristic of light in the first wavelength band and a reflection characteristic of light in the second wavelength band into a plurality of regions based on a predetermined reference. The area to which the point indicated by the first reflection characteristic and the second reflection characteristic on the two-dimensional plane belongs is specified, and the condition of the end of the optical cable is determined based on the area. The determination apparatus of claim 1.

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