JP5221072B2 - Cord control system and cord control method - Google Patents

Description

  The present invention relates to a cord contrast technique for specifying an optical fiber in order to avoid erroneous disconnection or erroneous connection of an optical fiber in the construction or maintenance of an optical fiber communication network.

  In the construction and maintenance of the optical fiber communication network, it is necessary to individually identify the optical fiber in the optical fiber cable or at the user's house at the work site so as not to cause an accidental disconnection or erroneous connection of the optical fiber. This operation is called cord control (for example, see Non-Patent Document 1).

  FIG. 5 is a block diagram showing an example of a conventional optical fiber reference system. A light signal for contrast (hereinafter referred to as “control light”) is sent from the light source device 2 for controlling the core wire to the optical fiber 1 via the incident device 3 for controlling the core wire, which is installed upstream of the optical fiber 1 that requires control. ) Is incident. On the downstream side of the optical fiber 1, the optical fiber 1 is bent by using the optical fiber 1 for detecting the optical fiber, so that the optical fiber 1 is radiated outside the optical fiber 1, and the optical control light is detected. .

  Here, the light source device 2 is a laser diode (LD) or a light emitting diode (LED: LED) having a longer wavelength than a communication optical signal (hereinafter referred to as “communication light”) that provides information to the user's home 18. It is a device that emits light obtained by applying frequency modulation of 270 Hz to light such as Light Emitting Diode). For example, when the communication light wavelength is 1.31 μm, the reference light wavelength is 1.55 μm, and when the communication light wavelength is 1.55 μm, the control light wavelength is 1.65 μm.

  Further, as the incident device 3, the reference light is directly incident from the optical fiber coupler, the waveguide type directional coupler, or the upstream end face of the optical fiber 1. The light receiving device 4 is provided with a bending mechanism for efficiently radiating only the reference light to the outside of the optical fiber 1 while suppressing the loss of communication light to a certain predetermined level. A reference optical signal light receiving element (hereinafter referred to as “light receiving element”) such as a Ge photodiode or an lnGaAs photodiode for receiving the emitted light is provided, and the presence or absence of the reference light is determined and the intensity is measured. be able to.

With such a configuration, even when communication light is being transmitted / received, the optical fiber 1 is detected by the downstream operator using the light receiving device 4 to detect the contrast light incident from the upstream side of the optical fiber 1, thereby performing the core line contrast. It had been.
Enomoto et al .: "Design of a compact optical fiber ID tester using a hybrid optical module", Proceedings of the 1996 IEICE Communication Society Conference (separate volume: Communication 2), lecture number B-976, p. 461

  FIG. 6 is a configuration diagram showing an example in which the optical fiber contrast device is applied to a branched optical communication system. 2 is a light source device for contrasting the core wire, 3 is an incident device for contrasting the core wire, 4 is a light receiving device for contrasting the core wire, 5 is an optical branching element, 6 is an upstream transmission device, 7-1, 7-2 7-n is a downstream transmission device, 9 is an upstream optical fiber, 10-1, 10-2, ... 10-n is a branch line. 6 is a PDS (Passive Double Star) type communication in which one upstream optical fiber 9 is branched into a plurality of branch lines 10-1, 10-2,... 10-n. It is a net. Since the reference light propagates to all the branch lines connected to the optical branch element 5, the branch lines 10-1, 10-2,... It was possible.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to make it possible to individually identify a branch line downstream from an optical branching element in a branched optical communication network such as a PDS type communication network.

  A core-line control system in a branched optical communication network, which monitors each communication between an upstream transmission device and a plurality of downstream transmission devices, and an error has occurred in communication with any downstream transmission device Is identified, a transmission path in which loss giving means is installed is specified between the upstream transmission apparatus and the downstream transmission apparatus.

Specifically, in the optical fiber reference system according to the present invention, one optical fiber connected to the upstream transmission device is connected to a plurality of branch lines each connected to the downstream transmission device by an optical branching element. In a core line contrast system that contrasts the cores of a branched optical communication system that is branched, the optical fiber is installed in any one of the plurality of branch lines, and the branch line is bent to cause bending loss. Loss imparting means for generating a communication error due to a code error in communication light transmitted and received between the connected downstream transmission apparatus and the upstream transmission apparatus, and closer to the upstream transmission apparatus than the optical branching element installed, the loss causing unit by said communication error by code errors occurred in the communication light is detected for each said downstream transmission device connected to the respective branch line loss detection And stage, the provided, gradually adding losses bent branch lines, downstream transmission apparatus for transmitting and receiving communication light there was a change in the detected communication error by the loss detecting means is connected by the loss causing means The core line is contrasted by specifying the branched line as a branched line to which bending loss is added by the loss applying means .
Since the loss detecting means detects the behavior of the communication error, the branch line in which the loss giving means is installed can be specified by comparing with the communication error generated by the loss giving means.

  Preferably, the loss giving means generates a communication error due to a code error that can be corrected in the branch optical communication system. Core line contrast can be performed without interfering with transmission / reception of communication light on the branch line that performs core line contrast.

Specifically, in the optical fiber reference method according to the present invention, one optical fiber connected to an upstream transmission device is connected to a plurality of branch lines each connected to a downstream transmission device by an optical branching element. A method of contrasting a core of a branched optical communication system that is branched, wherein in any of the plurality of branch lines, the branch line is bent to cause bending loss. A loss giving procedure for generating a communication error due to a code error in communication light transmitted and received between the connected downstream transmission apparatus and the upstream transmission apparatus; and on the upstream transmission apparatus side of the optical branching element. , anda loss detection step of detecting for each of the downstream transmission device connected to each of the communication error by the code error which is generated in the communication light in the loss causing instructions the branch lines, Serial loss causing procedure, it adds bending loss gradually branch lines in the branch line downstream transmission apparatus is connected to send and receive communication light where there is variation in the detected communication error by the loss detection procedure, the It is characterized in that the cords are contrasted by specifying as a branch line to which bending loss is added in the loss giving procedure .
Since the loss detection procedure detects the behavior of the communication error, it is possible to identify the branch line to which the loss has been given in the loss giving procedure by comparing with the communication error generated in the loss giving procedure.

  In the loss provision procedure, it is preferable to generate a communication error due to a code error that can be corrected by the branched optical communication system. Core line contrast can be performed without interfering with transmission / reception of communication light on the branch line that performs core line contrast.

  According to the present invention, the cores of the branch lines can be compared even in the branch optical communication network. Furthermore, it is possible to perform a cord contrast without using control light.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment. FIG. 1 is a configuration diagram showing a first example of a cord control system according to the present embodiment. In the optical fiber reference system according to the present embodiment, one optical fiber 9 is branched into a plurality of branch lines by the optical branching element 5. In the present embodiment, as an example, the plurality of branch lines are n branch lines 10-1, 10-2,. The downstream transmission devices 7-1, 7-2,... 7-n are connected to the branch lines 10-1, 10-2,.

  The downstream transmission devices 7-1, 7-2,... 7 -n respectively transmit and receive communication light with the upstream transmission device 6. The downstream transmission devices 7-1, 7-2,... The upstream transmission device 6 is a transmission device such as an OLT (Optical Line Terminal) arranged in a base station or a relay station, for example. The optical fiber 9 and the branch lines 10-1, 10-2,... 10-n are optical lines. The optical fiber 9 and the branch lines 10-1, 10-2,... 10-n may be a single mode or a multimode.

The cord control system according to the present embodiment includes a loss applying unit 8 and a loss detecting unit (not shown). There is no need for a light source device or an incident device for contrasting a conventional core wire. The loss detection means (not shown) is installed on the upstream side of the optical branching element 5, but is provided in the upstream transmission device 6 in the present embodiment.

  The loss giving means 8 bends the branch line 10-1 that is one of the n branch lines 10-1, 10-2,... 10-n. The loss imparting means 8 bends the branch line 10-1 to such an extent that a code error (communication error) occurs in communication light transmitted and received by the branch line 10-1.

  FIG. 2 is an explanatory view showing an example of the loss providing means. The loss imparting means 8 includes a convex portion 11 and a concave portion 12 that are curved in accordance with the shape of the bent optical fiber 13, and the optical fiber 13 is bent by sandwiching the optical fiber 13 between the convex portion 11 and the concave portion 12. . Here, the optical fiber 13 is the branch line 10-1 in FIG. 1 in this embodiment. Bending loss can be increased by narrowing the gap between the convex portion 11 and the concave portion 12. For example, when the gap between the convex portion 11 and the concave portion 12 is wide and the bending amount of the optical fiber 13 is small, the bending loss is small. On the other hand, when the gap between the convex portion 11 and the concave portion 12 is narrow and the bending amount of the optical fiber 13 is large, the bending loss is large. The loss imparting means 8 bends the optical fiber 13 to such an extent that the communication light transmitted by the optical fiber 13 does not break the link.

  In FIG. 1, the loss detection means (not shown) detects the code error generated by the loss giving means 8. Loss detection means (not shown) is provided in the upstream transmission device 6, for example. In this case, the upstream transmission device 6 independently detects a code error (communication error) in each optical communication with the downstream transmission devices 7-1, 7-2,... 7-n. The loss detecting means detects the code error for each of the branch lines 10-1, 10-2,..., 10-n, so that the loss giving means 8 can detect the branch line 10-1 in which the code error is generated. .

  A method for contrasting core wires according to the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing an example of the method for contrasting core wires according to the present embodiment. The cord contrast method according to the present embodiment is characterized by having a loss providing procedure S102 and a loss detecting procedure S103. In the present embodiment, a confirmation procedure S101 is provided before the loss provision procedure S102. Further, after the loss detection procedure S103, there are a bending procedure S104 and a completion procedure S105.

  In the confirmation procedure S101, the operator makes an inquiry to the upstream transmission device 6 using a mobile phone or the like, and a communication error has occurred with all the downstream transmission devices 7-1, 7-2,. Make sure there is no. In the loss giving procedure S102, one branch line 10-1 among the plurality of n branch lines 10-1, 10-2,... Bend 1 By causing bending loss, a communication error due to a code error is generated.

  In the loss detection procedure S103, a communication error due to the code error generated in the loss assignment procedure S102 is detected. For example, the loss detection means provided in the upstream transmission device 6 confirms whether a communication error due to a code error has occurred in any of the branch lines 10-1, 10-2,. When the bending of the branch line 10-1 by the loss applying means 8 is small, no code error occurs. When there are a plurality of similar code errors, the process proceeds to the bending procedure S104.

  Since the branch line 10-1 bent by the loss applying unit 8 increases in loss, a code error (communication error) occurs in the optical signal between the upstream transmission device 6 and the downstream transmission device 7-1. Occur. At this time, no code error occurs in communication via the branch lines 10-2,. The code error is detected by the loss detection means provided in the upstream transmission apparatus 6, and the corresponding code error occurs on the communication path between the upstream transmission apparatus 6 and the downstream transmission apparatus 7-1, that is, on the branch line 10-1. At the same time, it is confirmed that no code error has occurred in the other branch lines 10-2,. Thereby, it is confirmed that the branch line 10-1 given the bending loss by the loss applying means 8 is a communication path connecting the upstream transmission device 6 and the downstream transmission device 7-1.

  If a communication error cannot be detected in the loss detection procedure S103, the process proceeds to the bending procedure S104. In the bending procedure S104, the loss imparting means 8 strengthens the bending of the branch line 10-1. Here, also in the loss providing procedure S104, it is preferable to generate a code error that can be corrected in the branch optical communication system.

  On the other hand, in the loss detection procedure S103, when a communication error is detected only from one set of transmission paths between the upstream transmission device 6 and the downstream transmission device 7-1, the process proceeds to the completion procedure S105. In the completion procedure S105, it is confirmed that the branch line 10-1 given the bending loss by the loss applying means 8 is a communication path connecting the upstream transmission device 6 and the downstream transmission device 7-1.

  In the cord contrast method according to the present embodiment, by having the bending procedure S104, the loss applying unit 8 gradually increases the communication error detected by the loss detecting unit arranged in the upstream transmission device 6 in real time. Bending loss is added to the branch line 10-1. Since the branch line 10-1 can be specified by the fluctuation of the communication error, the branch line 10-1 to which the bending loss is applied by the loss applying means 8 can be specified easily and reliably.

  As described above, by using the core line contrast system or the core line contrast method according to the present embodiment, it is possible to perform the core line contrast even in the branched optical communication network. Without going back to the optical branching element 5 along the branch line, it is possible to individually perform the core line contrast at the terminal portion of the upstream transmission device 6. Further, since the reference light incident on the optical fiber is not necessary, the core contrast can be performed without preparing a light source for the core contrast.

  In the core line contrast system according to the present embodiment, it is preferable that the loss imparting means 8 shown in FIG. 1 generates a code error that can be corrected in the branched optical communication system. Further, in the loss detection procedure S103 shown in FIG. 3, a code error that can be corrected in the branch optical communication system is generated. If the sign error generated by the loss giving means 8 shown in FIG. 1 can be corrected in the branch optical communication system, the cores are compared even while the optical communication service is provided using the branch line 10-1. be able to.

  As a method for correcting an error in a branched optical communication system, for example, there is a retransmission request method or an error correction method. If the error correction method used in the branch optical communication system is a retransmission request method, the loss providing unit 8 generates a communication error to the extent that a retransmission request starts to be issued. On the other hand, if the error correction method used in the branching optical communication system is an error correction method, the loss providing unit 8 generates a communication error within a range that can be corrected by the error correction method.

  FIG. 4 is a configuration diagram illustrating a second example of the core line control system according to the present embodiment. In the core line contrast system shown in FIG. 4, the core line contrast system corrects the communication error by the retransmission request method. In this case, the core line control system includes an error detection circuit 15, a retransmission request circuit 16, and a retransmission circuit 14.

  The downstream transmission device 7-1 receives the communication light transmitted from the upstream transmission device 6. At this time, the error detection circuit 15 measures a communication error of a signal obtained by the received communication light. If the retransmission request circuit 16 determines that the communication error is greater than or equal to a predetermined value, the retransmission request circuit 16 transmits a retransmission request to the upstream transmission apparatus 6. When the upstream transmission apparatus 6 receives the retransmission request, the retransmission circuit 14 again transmits the correct code of the incorrect code part. At this time, the loss giving means 8 generates a communication error at the boundary of whether or not the retransmission request circuit 16 transmits a retransmission request, so that the transmission between the upstream transmission device 6 and the downstream transmission device 7-1. Communication can be maintained.

  When the error correction method used in the branch optical communication system is an error correction method, an error correction circuit is provided instead of the retransmission request circuit 16, and an error correction code generation circuit is provided instead of the retransmission circuit 14. The error correction code generation circuit adds an error correction code to information to be transmitted to the downstream transmission device 7-1. When the error detection circuit 15 detects an error, the error correction circuit corrects the code error based on the error correction code. At this time, the loss giving means 8 can maintain communication between the upstream transmission device 6 and the downstream transmission device 7-1 by generating a communication error within a range in which the code error can be corrected. it can.

  The error correction code varies depending on the generated error, but is not limited in the present embodiment. If the generated error is a random error, the error correction code is, for example, a random error correction code such as a Hamming code, a BHC code, a convolutional code by Viterbi decoding or sequential decoding, a self-orthogonal code, or a horizontal / vertical parity check code. If the generated error is a byte error, the error correction code is, for example, a Reed-Solomon code. If the generated error is a burst error, the error correction code is, for example, a fire code, a bulk code, an Iwadare code, or a Hagelburger code.

  As described above, if the code error generated by the loss giving means 8 can be corrected in the branch optical communication system, the optical fiber line control is used even when the optical communication service is provided using the branch line 10-1. It can be performed. Here, when correction of the communication error is performed on the upstream side before the branching, it is necessary to detect the communication error for the control of the cores before correcting the communication error. In the core line control system and the core line control method according to the present embodiment, the detection of the communication error for the core line control is on the upstream side of the upstream transmission device 6 or the like, whereas the detection for the correction of the communication error is performed. Since this is a downstream communication device, it is possible to perform the contrast control without being affected by the correction of the communication error.

  Note that the error detection circuit and the retransmission request circuit may be provided not only in the downstream transmission device 7-1 but also in the upstream transmission device 6. In this case, the retransmission circuit is provided in the downstream transmission device 7-1. In the case of two-core bidirectional communication, it is preferable to provide an error detection circuit, a retransmission request circuit, and a retransmission circuit in the upstream transmission device 6 and the downstream transmission device 7-1. Moreover, although this embodiment demonstrated the example which provides an error detection circuit and a resending request circuit in the downstream transmission apparatus 7-1 among downstream transmission apparatuses, downstream transmission apparatuses 7-1, 7-2, ... It is preferable to provide each of 7-n.

  It can be used for construction and maintenance of optical fiber communication networks.

It is a block diagram which shows the 1st example of the core line contrast system which concerns on this embodiment. It is explanatory drawing which shows an example of a loss provision means. It is a flowchart which shows an example of the core line contrast method which concerns on this embodiment. It is a block diagram which shows the 2nd example of the core line contrast system which concerns on this embodiment. It is a block diagram which shows an example of the conventional optical fiber contrast system. It is a block diagram which shows an example which applied the core line contrast apparatus to the PDS type | mold communication network.

Explanation of symbols

2 Light source device for optical fiber comparison 3 Incident device for optical fiber comparison 4 Light receiving device for optical fiber comparison 5 Optical branching element 6 Upstream transmission device 7-1, 7-2,... 7 -n Downstream transmission device 8 Loss giving means 9 Optical fibers 10-1, 10-2,... 10-n Branch line 11 Convex part of loss giving means 12 Concave part of loss giving means 13 Optical fiber 14 Retransmission circuit 15 Error detection circuit 16 Retransmission request circuit 18 User's house

Claims (4)

A core that contrasts the cores of a branched optical communication system in which one optical fiber connected to an upstream transmission device is branched to a plurality of branch lines each connected to a downstream transmission device by an optical branching element. In the line control system,
It is installed in any of the plurality of branch lines, and is transmitted / received between the downstream transmission apparatus and the upstream transmission apparatus connected to the branch line by bending the branch line to cause a bending loss. Loss giving means for generating a communication error due to a code error in the communication light,
Than the optical branching device installed on the upstream transmission apparatus, a communication error due to bit error occurring in the communication light for each of the downstream transmission device connected to each of the branch lines by the loss causing means Loss detecting means for detecting;
Provided,
Gradually adding losses bent branch lines, branch lines downstream transmission apparatus is connected to send and receive communication light where there is variation in the detected communication error by the loss detecting means by said loss causing means, said A cord contrast system characterized in that the cord contrast is performed by specifying as a branch line to which bending loss is added by a loss applying means .   2. The cord control system according to claim 1, wherein the loss giving means generates a communication error due to a code error that can be corrected in a branch optical communication system. A core that contrasts the cores of a branched optical communication system in which one optical fiber connected to an upstream transmission device is branched to a plurality of branch lines each connected to a downstream transmission device by an optical branching element. A line contrast method,
Communication transmitted and received between the downstream transmission device and the upstream transmission device connected to the branch line by bending the branch line to cause a bending loss in any of the plurality of branch lines. Loss imparting procedure that causes a communication error due to a code error in light;
In the upstream transmission device side of the optical branching device, detects a communication error due to code error that caused the communication light in the loss causing procedure for each of the downstream transmission device connected to each of the branch lines Loss detection procedure to
Have
The loss causing procedure, it adds bending loss gradually branch lines in the branch line downstream transmission apparatus is connected to send and receive communication light where there is variation in the detected communication error by the loss detection procedure, the A cord contrast method characterized by performing cord contrast by specifying a branch line to which bending loss is added in the loss applying procedure .   4. The method according to claim 3, wherein a communication error due to a code error that can be corrected by the branched optical communication system is generated in the loss providing procedure.

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