JP2012205284A - Detection device and detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow checking the presence or absence of an optical network unit (ONU) without visually checking the device of the optical network unit .SOLUTION: A detection device deforms an optical cable to be used for an optical communication network, receives light leaked from the deformed portion to generate electric signals, allows passage of electric signals included in the generated electric signals and corresponding to the transmission period of light transmitted from the optical network unit disposed on a subscriber side, determines the presence or absence of light according to the intensity of the electric signals having passed through a filter, and displays the result of the determination.

Description

  The present invention relates to a technique for detecting an ONU (Optical Network Unit: optical line terminator) arranged on a subscriber side.

  As the number of subscribers to the optical access network increases, there are cases where the optical cable of the optical access network is drawn into the homes of persons who have not actually joined the optical access network (non-subscribers). In newly built apartment buildings and the like in recent years, optical cables are often drawn in advance regardless of whether they are joined or not. When a non-subscriber wishes to join, it is possible to receive a service by connecting the ONU to the optical cable already drawn in without having to bother to draw the optical cable into the house.

  When inspecting or constructing an optical cable for an optical access network, it is necessary to check whether the optical cable drawn into each house is actually used for communication in order to prevent accidents such as disconnection of the line. is there. Such an inspection is generally performed based on whether an ONU is connected to the end of an optical cable. That is, if the ONU is connected to the end of the optical cable, this indicates that the optical cable is actually used for communication. On the other hand, if the ONU is not connected to the end of the optical cable, it indicates that the optical cable is not used for communication. Specifically, the inspection is performed by an inspector entering the house and confirming whether there is an ONU.

JP 2010-252192 A

  However, since the presence or absence of the ONU cannot be confirmed without entering the home, various problems arise. For example, since it is impossible to enter the absence home, it is not possible to confirm whether there is an ONU. There is also a method to contact the day when you enter the house in advance so that you will not be away, but it will take time for the inspection side to establish the schedule, and the side to witness will also have to make a schedule, burdening both sides It was over.

  In view of the above circumstances, an object of the present invention is to provide a technique that enables the presence or absence of an optical line termination device to be confirmed without visually confirming an optical line termination unit (ONU).

  One aspect of the present invention is a detection device that deforms an optical cable used in an optical communication network, receives light leaking from the deformed portion, and generates an electrical signal; A filter unit that passes an electrical signal corresponding to a transmission period of burst-like light transmitted from an optical line terminator arranged on the user side, and the burst state based on the intensity of the electrical signal that has passed through the filter unit A determination unit that determines the presence or absence of light, and a display unit that displays a determination result by the determination unit.

  One aspect of the present invention is the above-described detection device, wherein the leakage light acquisition unit includes a plurality of light reception units, and some of the light reception units receive light leaked from one of the optical cables to the other. The other light receiving unit receives light leaking from one of the optical cables to the other, and the determination unit receives the light received by the one light receiving unit and the other light receiving unit. And determining whether the burst-like light has flowed from one side to the other or the other to the other, and the display unit detects the direction in which the burst-like light has flowed as a detection result. indicate.

  One aspect of the present invention is a detection method, in which a detection device deforms an optical cable used in an optical communication network, receives light leaking from the deformed portion, and generates an electrical signal, and the detection device includes: The filter step of passing the electrical signal according to the transmission period of the burst-like light transmitted from the optical line terminating device arranged on the subscriber side out of the electrical signal, and the detection device pass in the filter step A determination step for determining the presence or absence of the burst-like light based on the intensity of the electrical signal, and a display step for displaying a determination result by the determination step.

  According to the present invention, it is possible to confirm the presence or absence of an optical line terminator without visually confirming the apparatus of the optical line terminator (ONU).

1 is a system configuration diagram showing a configuration of an optical communication system. 1 is a system configuration diagram illustrating a detailed specific example of an optical communication system. It is a functional block diagram showing the functional structure of a detection apparatus. It is a figure showing the outline of the amplification process by a leak light acquisition part. It is a figure showing the example of a structure of a leak light acquisition part. It is a figure which shows the concept of the light reception by a light receiving element. It is a figure showing the structure of a filter part. It is a figure which shows the example of a display of a display part.

FIG. 1 is a system configuration diagram showing the configuration of the optical communication system 1. The optical communication system 1 includes an OLT (Optical Line Terminal) 10, an optical cable 20, an optical branching element 30, and an ONU 40. The optical cable 20 connects the OLT 10 and the optical branch element 30, and connects the optical branch element 30 and the ONU 40.
The OLT 10 is an optical line termination device installed on the telecommunications carrier side. The light emitted from the OLT 10 toward the ONU 40 travels through the optical cable 20 and reaches the optical branching element 30. The optical branching element 30 branches light transmitted through the optical cable 20 into a plurality of optical cables 20. Each light branched by the optical branching element 30 travels through the optical cable 20 and reaches the ONU 40.

In the optical communication system 1, a direction from the OLT 10 toward the ONU 40 is referred to as a “downward direction”, and a direction from the ONU 40 toward the OLT 10 is referred to as an “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 40 transmits a signal using burst-like light (hereinafter referred to as “burst light”) in a predetermined period. Therefore, upstream light is generated in a predetermined cycle in the optical cable 20 to which the ONU 40 is connected. Also, upstream light is generated at a predetermined cycle in the optical cable 20 connected to the ONU 40 and the optical cable 20 connected via the optical branching element 30.

  The detection device 60 is a device that detects the presence of an ONU. The detection device 60 determines whether the ONU 40 is connected to the tip of the optical cable 20 in the downward direction by sandwiching the optical cable 20. The optical cable 20 sandwiched by the detection device 60 may be the optical cable 20 from the OLT 10 to the optical branching element 30 or the optical cable 20 from the optical branching element 30 to the ONU 40. The detection device 60 detects the presence of the ONU 40 by detecting the burst light emitted from the ONU 40.

  FIG. 2 is a system configuration diagram illustrating a detailed specific example of the optical communication system 1. The optical communication system 1 illustrated in FIG. 2 includes a video distribution OLT 101, an IP communication OLT 102, a branch wiring closure 301, a drop closure 302, and an ONU 40. The video distribution OLT 101 and the IP communication OLT 102 are specific examples of the OLT 10. The video distribution OLT 101 transmits downstream light having a wavelength of 1.55 micrometers, and the IP communication OLT 102 transmits downstream light having a wavelength of 1.49 micrometers.

The branch wiring closure 301 and the drop closure 302 are specific examples of the optical branching element 30. The branch wiring closure 301 is installed on the wiring pillar and is connected to the optical cable 20 that has been pulled up from the ground to the air along the pulling pillar. The branch wiring closure 301 branches downstream light transmitted from the video distribution OLT 101 and the IP communication OLT 102 to the optical cables 20. The drop closure 302 is installed on the drop pillar and connected to the optical cable 20 branched by the branch wiring closure 301. The drop closure 302 branches the light branched by the branch wiring closure 301 to the ONU 40.
The ONU 40 transmits upstream light having a wavelength in the 1.31 micrometer band. The upstream light emitted from the ONU 40 is pulled down via the optical cable 20 and reaches the closure 302, further reaches the branch wiring closure 301 via the optical cable 20, and further via the optical cable 20 for video distribution OLT 101 and IP communication The OLT 102 is reached.

  In the optical communication system 1 shown in FIG. 2, the optical cable sandwiched by the detection device 60 may be the optical cable 20 that is part of the optical cable 20 between the ONU 40 and the closure 302 that is out of the house. The optical cable 20 sandwiched by the detection device 60 may be the optical cable 20 between the drop closure 302 and the branch wiring closure 301, or between the branch wiring closure 301 and the video distribution OLT 101 and the IP communication OLT 102. The optical cable 20 may be used. However, the detection result obtained by the detection device 60 is whether or not the ONU 40 is installed in the downward direction of the sandwiched optical cable 20. Therefore, only a rough detection result can be obtained as the position where the optical cable 20 is sandwiched is closer to the video delivery OLT 101 and the IP communication OLT 102. For example, when the optical cable 20 between the ONU 40 and the closure 302 is sandwiched, the optical cable 20 reaches the ONU 40 without being branched, so whether the ONU 40 is installed with respect to the optical cable 20 or not. It can be detected.

  On the other hand, when an optical cable between the drop closure 302 and the branch wiring closure 301 is sandwiched, the optical cable may be branched by the drop closure 302. It is whether ONU40 is installed in any one of these. If the ONU 40 is installed in any one of the plurality of branch destination optical cables 20, the detection device 60 detects that the ONU 40 exists. Therefore, even if there is an optical cable 20 in which the ONU 40 is not installed in the branch destination, it is not possible to detect which optical cable 20 it is. The same applies when the optical cable 20 between the branch wiring closure 301 and the video delivery OLT 101 and the IP communication OLT 102 is sandwiched. Therefore, the position where the optical cable 20 is sandwiched between the detection devices 60 needs to be appropriately determined according to the inspection target.

  FIG. 3 is a functional block diagram illustrating a functional configuration of the detection device 60. The detection device 60 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and executes a detection program. The detection device 60 functions as a device including a leakage light acquisition unit 601, a filter unit 602, a determination unit 603, and a display unit 604 by executing a detection program. All or a part of each function of the detection device 60 may be realized by using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA). The detection program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system.

  The leak light acquisition unit 601 deforms the optical cable 20 by sandwiching the optical cable 20. The leaked light acquisition unit 601 receives light leaked from the optical cable 20 by deformation (hereinafter referred to as “leakage light”), and generates and amplifies an electrical signal corresponding to the intensity of the received light. FIG. 4 is a diagram illustrating an outline of the amplification process performed by the leaked light acquisition unit 601. FIG. 4A represents leakage light. FIG. 4B shows the signal after amplifying the electrical signal according to the intensity of the leaked light. When a leaked light acquisition unit 601 amplifies the generated electrical signal, the leaked light acquisition unit 601 captures the burst-like upstream signal as a lump pulse waveform and outputs it to the filter unit 602.

  The filter unit 602 is a filter that passes an electrical signal generated according to burst light (hereinafter, referred to as “burst optical electrical signal”) among electrical signals output from the leaked light acquisition unit 601. For example, the filter unit 602 is configured as a band-pass filter having a burst period of the burst photoelectric signal. The filter unit 602 may be configured as a digital filter, for example. Since the filter unit 602 is configured as a digital filter, the noise is effectively blocked even when the frequency of the noise to be blocked and the burst period of the signal to be passed (burst photoelectric signal) are close. It is possible to pass a burst photoelectric signal without being excessively attenuated.

The determination unit 603 determines whether or not the burst optical electrical signal is included in the electrical signal that has passed through the filter unit 602. In the determination unit 603, a threshold value of the intensity of the electric signal is set in advance. The determination unit 603 determines whether there is a burst photoelectric signal based on the threshold value. The determination unit 604 notifies the display unit 604 of the detection result.
The display unit 604 is configured using an image display device such as a liquid crystal display or an organic EL (Electro Luminescence) display. The display unit 604 displays the determination result by the determination unit 603.

  FIG. 5 is a diagram illustrating a configuration example of the leakage light acquisition unit 601. FIG. 5A is a front view when looking down from above, and FIG. 5B is a perspective view. The leakage light acquisition unit 601 includes a first wall 6011, a second wall 6012, an optical cable path 6013, and a light receiving unit 6014. The first wall portion 6011 and the second wall portion 6012 are wall surfaces having a width in a direction substantially perpendicular to the paper surface of FIG. 5A, and form an optical cable path 6013 sandwiched between both wall surfaces. The first wall portion 6011 is formed in a convex shape toward the second wall portion 6012. For example, as illustrated, the first wall portion 6011 has a convex portion that extends toward the second wall portion 6012. The wall surface of the second wall portion 6012 is configured to be recessed in a direction away from the first wall portion 6011 as illustrated. The optical cable path 6013 is a path through which the optical cable 20 passes. The optical cable 20 that has passed through the optical cable path 6013 is sandwiched between the first wall portion 6011 and the second wall portion 6012, and is thus deformed into a convex shape on the side where the light receiving portion 6014 is disposed. Note that a more detailed configuration for acquiring light leaking from an optical cable is disclosed in Japanese Patent Application Laid-Open No. 2010-121968, and the disclosed configuration can be employed.

  FIG. 6 is a diagram illustrating the concept of light reception by the light receiving element 6014. As shown in FIG. 6, upstream light and downstream light leak from the convex portion of the optical cable 20 that has been deformed. When the OLT 10 is installed on the left side and the ONU 40 is installed on the right side as shown in FIG. 6, the leaked light of the upstream light is received by the light receiving element 6014a disposed on the left side, and the leaked light of the downstream light is disposed on the right side. Light is received by the light receiving element 6014b. Note that the light receiving element 6014a and the light receiving element 6014b may receive not only the upstream leakage light and the downstream leakage light but also other light. The light receiving element 6014a and the light receiving element 6014b each output an electrical signal generated by receiving the leaked light to the filter unit 602. The electrical signal output to the filter unit 602 passes through the filter unit 602. Based on the electric signal output from the light receiving element 6012a and the electric signal output from the light receiving element 6014b, the determination unit 603 determines whether the upward direction is based on which light receiving element has detected the burst photoelectric signal. It is determined whether it is left or right or the down direction is left or right.

FIG. 7 is a diagram illustrating the configuration of the filter unit 602. FIG. 7A is a diagram illustrating an electrical signal input to the filter unit 602 and a filter of the filter unit 602. FIG. 7B is a diagram illustrating an electrical signal that has passed through the filter unit 602. 7A and 7B, the horizontal axis represents the period, and the vertical axis represents the strength of the electric signal. The burst light and noise change with different periods. The filter unit 602 is a band-pass filter having characteristics as indicated by a curve 80, for example. That is, the filter unit 602 passes a signal having a period in which a burst photoelectric signal is generated, and blocks a signal having another period. Therefore, in the electric signal that has passed through the filter unit 602, the burst photoelectric electric signal is hardly attenuated as shown in FIG. 7B, and signals in other periods are greatly attenuated.
The determination unit 603 determines that there is a burst photoelectric signal when there is a signal having an intensity exceeding a preset threshold in the electrical signal that has passed through the filter unit 602. On the other hand, the determination unit 603 determines that there is no burst photoelectric signal when there is no signal having an intensity exceeding a preset threshold in the electrical signal that has passed through the filter unit 602.

  FIG. 8 is a diagram illustrating a display example of the display unit 604. The display unit 604 includes a left direction display unit 6041, a right direction display unit 6042, a detection level display unit 6043, and a no-signal display unit 6044. The left direction display unit 6041 and the right direction display unit 6042 indicate which side the down direction is. When the right side of the sandwiched optical cable 20 is the up direction and the left side is the down direction, the left direction display unit 6041 is lit. When the left side of the sandwiched optical cable 20 is the up direction and the right side is the down direction, the right direction display unit 6042 is lit. The detection level display unit 6043 displays the detected upstream light intensity (intensity after passing through the filter unit 602) and the detected downstream light intensity (intensity measured by a measurement unit (not shown)). . The value displayed on the detection level display unit 6043 may be the largest value among the values measured in the respective directions, for example. The no-signal display unit 6044 indicates whether or not a burst photoelectric signal is detected by the determination unit 603. For example, when a burst photoelectric signal is detected by the determination unit 603, the no-signal display unit 6044 is not lit. On the other hand, when no burst photoelectric signal is detected by the determination unit 603, the no-signal display unit 6044 is lit.

  In the first place, upstream light has a very short period of the order of a few microseconds, so it is very difficult to detect. In general, the leakage light has the property of being less likely to leak as the wavelength becomes shorter. Of the three lights, upstream light and downstream light, the light having the shortest wavelength is upstream light. Therefore, the upstream light to be detected is most difficult to leak, and the level of the downstream light leakage light may be higher under the worst conditions when a video signal exists. Further, the downstream light may include a noise component in the vicinity of the cycle (frequency) of the upstream light burst signal to be detected. Furthermore, depending on the design of the housing that houses the optical branching element 30, the strand portion of the optical cable 20 may be lost, and the optical cable 20 surrounded by the protective tube may need to be sandwiched between detection devices. In such a case, the ONU 40 must be detected based on a small amount of light leaking through the protective tube. For such a problem, since the leaked light is amplified, the burst light can be detected with high accuracy even in the above situation.

  In addition, an electric signal due to light other than the burst light to be detected (for example, light in the downward direction) is also amplified, and the detection accuracy of the burst light may be reduced. For such a problem, the detection accuracy of burst light is improved by using a digital filter that blocks light in a band other than the frequency band of burst light.

For example, the detection device 60 can be used in the following situations.
At the time of releasing the hold, that is, when trying to cut the optical cable 20 that is on hold or not removed, it can be determined using the detection device 60 whether the optical cable 20 is in use. If it is not currently used, the optical cable 20 may be cut and removed, or cut and diverted to another house.
When the optical cable for wiring is cut during the opening work, it is possible to determine whether or not the optical cable 20 designated by the wire number is in use by using the detection device 60. Therefore, it is possible to cut the optical cable for wiring after confirming that it is not currently used.

It is possible to confirm whether or not communication has been restored by using the detection device 60 without looking at the ONU 40 when repairing the failure.
When it is managed whether or not each optical cable 20 is currently used in the database, it is possible to easily determine whether or not the contents of the database are correct by examining each optical cable 20 with the detection device 60 in the field. . If the contents of the database are incorrect, it can be easily corrected.

<Modification>
The configuration of the leakage light acquisition unit 601 described above is merely an example, and for example, the light receiving unit 6014 may be configured by one light receiving element. Hereinafter, the detection device 60 configured in this way will be described. The light receiving element receives the upstream leakage light and the downstream leakage light. The determination unit 603 detects the burst photoelectric signal without distinguishing whether it is upstream leakage light or downstream leakage light. The display unit 604 does not include the left direction display unit 6041 and the right direction display unit 6042, and does not display which is the down direction or the up direction. Even in such a configuration, the ONU 40 can be detected based on the presence or absence of burst light.

The display mode of the display unit 604 described above is merely an example, and may be configured differently. For example, the no-signal display unit 6044 may be lit when a burst photoelectric signal is detected by the determination unit 603, and the no-signal display unit 6044 may not be lit when a burst photoelectric signal is not detected.
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 designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... OLT, 20 ... Optical cable, 30 ... Optical branching element, 40 ... ONU, 60 ... Detection apparatus, 601 ... Leakage light acquisition part, 602 ... Filter part, 603 ... Determination part, 604 ... Display part, 6011 ... First wall , 6012 ... second wall part, 6013 ... optical cable path, 6014 ... light receiving part, 80 ... curve (band pass filter), 6041 ... left direction display part, 6042 ... right direction display part, 6043 ... detection level display part, 6044 ... No signal display

Claims (3)

A leakage light acquisition unit that deforms an optical cable used in an optical communication network, receives light leaking from the deformation part, and generates an electrical signal;
Among the electrical signals, a filter unit that passes an electrical signal corresponding to a transmission period of burst-like light transmitted from an optical line terminating device arranged on the subscriber side;
A determination unit that determines the presence or absence of the burst-shaped light based on the intensity of the electrical signal that has passed through the filter unit;
A display unit for displaying a determination result by the determination unit;
A detection device comprising: The leakage light acquisition unit includes a plurality of light receiving units, a part of the light receiving units receive light leaked from one of the optical cables to the other, and the other light receiving unit receives one from the other of the optical cables. Receive the leaked light flowing through the
Based on the light received by the part of the light receiving unit and the light received by the other light receiving unit, the determination unit may flow the bursty light from one to the other or from the other to the other. Judge whether it flowed,
The detection device according to claim 1, wherein the display unit displays a direction in which the burst-like light flows as a detection result. A detection device, which deforms an optical cable used for an optical communication network, receives light leaking from the deformed portion and generates an electrical signal;
A filter step in which the detection device passes an electrical signal corresponding to a transmission period of burst-like light transmitted from the optical line termination device arranged on the subscriber side among the electrical signals;
A determination step in which the detection device determines the presence or absence of the bursty light based on the intensity of the electrical signal passed in the filter step;
A display step in which the detection device displays the determination result of the determination step;
A detection method comprising:

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