JP2009265511A - Optical core wire discrimination device and optical core wire discrimination method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem of a conventional core wire discrimination method: a light source of 1,550 nm, which is used as a discrimination light source, cannot be used for discrimination of an in-use line since it interferes with communication light. <P>SOLUTION: The optical core wire discrimination device for discriminating a desired optical fiber core wire from a plurality of optical fiber core wires used in an optical multiple branch communication system comprises: a discrimination light source which emits a discrimination light having a wavelength longer than 1,550 nm and shorter than 1,650 nm from a subscriber-side end part of the desired optical fiber core wire; and a discrimination machine which measures leak of the discrimination light in a discrimination part between an optical fiber branch part and the subscriber-side end part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical core discriminating device used for performing live line judgment of an optical transmission line such as an optical fiber, and an optical core disc discriminating method using the same.

  As a communication system using an optical fiber, communication using a PON (Passive Optical Network) system as shown in FIG. 4 is known. In the PON communication system 1, downstream communication light from a transmission device (OLT: Optical Line Terminal) 10 of a carrier station is branched by an optical splitter 3 and transmitted to a plurality of subscriber-side ONUs (Optical Network Units) 20. .

In Patent Document 1, as an optical PDS (Passive Double Star) communication system 1, in order to monitor an abnormality of an optical fiber or an optical communication device that is an optical line medium, an assigned unique monitoring wavelength (λ _c1 to λ _c8 ), each of the slave station devices (ONU) 20 including the reflection filters 20-1 to 20-8 and the intensity of each monitoring wavelength light at the input ends of the reflection filters 20-1 to 20-8. An output control means including an OLT 10 that emits each monitoring wavelength light so as to be less than the minimum reception intensity of the ONU 20 is described.

That is, in this system, each monitoring wavelength light is emitted from the OLT 10 side, and the monitoring wavelength light is branched into light having a specific monitoring wavelength (λ _{c1 to} λ _c8 ) assigned to each slave station device by the optical splitter 3. Is done. The monitoring light is set to be less than the minimum receiving sensitivity and is not received by the light receiving unit, so that it does not affect the communication.

  By the way, in the PDS communication system 1 having the above configuration, for example, when there is an application for abolition of one ONU 20 (referred to as ONU-1) and it is intended to remove the line from the optical splitter 3 to the ONU-1, At a point on the exit side of the optical splitter 3, it is determined to which port of the optical splitter 3 the ONU-1 is connected.

  Further, in the current construction method, the optical fiber core wire is not connected to the optical splitter 3 until it is necessary, but the optical fiber core wire is connected in order from the slave station device side when the line is opened. Next, it is determined which optical fiber core wire is connected.

As a method of discriminating unused ones from a plurality of core wires stored in an optical fiber cable, a special optical signal (for example, an optical signal modulated to a frequency of 270 Hz) is usually sent from the master station of the core wire. In addition, there is known a technique in which a detection circuit discriminates a light received and detected by using a light receiving element on the other end side.
JP 2005-192138 A

  In the PDS communication system 1, in order to detect an optical fiber core wire that has not been used or has been stopped, in the conventional core wire discrimination method, light having a wavelength of 1550 nm is incident as discrimination light from the OLT 10 side, and the discrimination is performed. However, the communication light in the downstream (direction from the OLT 10 side to the ONU 20 side) is usually in the 1550 nm band. When determining the line in use, the communication light is used. In some cases, it could not be used because of interference with light.

  The present invention has been made to solve these problems, and provides an optical core discriminating method capable of discriminating a desired optical core wire without causing interference with communication light of a working line. With the goal.

  A first aspect of the optical fiber identification device according to the present invention is an optical fiber determination device that determines a desired optical fiber from a plurality of optical fibers used in an optical multi-branch communication system, A discrimination light source for entering discrimination light having a wavelength longer than 1550 nm and shorter than 1650 nm from a subscriber-side end of the desired optical fiber core, and between the optical fiber branch and the subscriber-side end The discriminator comprises a discriminator for measuring leakage of the discriminating light.

  According to this aspect, since discrimination light having a wavelength longer than 1550 nm and shorter than 1650 nm is incident from the end on the subscriber side, from among a plurality of optical fiber cores housed in an outdoor closure or the like, A desired optical fiber core wire can be discriminated without interference between discrimination light and communication light.

  In another aspect of the optical fiber identification device according to the present invention, the light source for determination includes a light blocking unit that blocks light having a wavelength of 1550 nm or less.

  According to this aspect, it is possible to prevent light such as communication light and monitoring light incident from the OLT side from entering the discrimination light source, and to prevent the output of the discrimination light source from becoming unstable. it can.

  According to the present invention, an optical core discriminating apparatus capable of easily discriminating a desired optical fiber core wire from a plurality of optical fiber core wires without causing interference with communication light on a working line, and the same It is possible to provide a method for discriminating an optical fiber using the.

  A method for discriminating an optical fiber in a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

  The optical fiber identification device according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a schematic diagram showing the entire PON communication system and an optical core discriminating apparatus according to the first embodiment of the present invention.

As shown in FIG. 1, in the PDS communication system 1, the downstream signal light 40 enters from the OLT and is branched by the optical splitter 30. The branched downstream signal light 40 reaches each ONU. Further, the upstream signal light 42 from each ONU is multiplexed by the optical splitter 30 and input to the OLT 10. Here, generally, signal light having a wavelength of 1550 nm is used for the downstream signal 40, and signal light having a wavelength of 1300 nm is used for the upstream signal 42.
Further, a filter 103 that reflects the monitoring light incident from the OLT 10 is inserted in front of the ONU 20 in the connector or the like, and this filter cannot be normally removed.

The optical fiber identification device 100 is longer than 1550 nm and shorter than 1650 nm from the ONU side end 130 of the optical fiber core 120 that is no longer used, and particularly shorter than the wavelength reflected by the monitoring light reflection filter 103. A discrimination light source 102 that receives a wavelength discrimination light 44 and a discriminator 104 that measures leakage of discrimination light in the discrimination unit of the optical fiber core 120 are provided.

  The discrimination light 44 generated by the discrimination light source 102 is incident in the upward direction (from the ONU side toward the OLT side) from the ONU side end portion 130 of the unused line. In the optical fiber identification device according to the present embodiment, when the optical fiber core 120 passes through the determination unit, the determination light 44 leaked by the determination unit is measured by the determination unit 104, and a plurality of optical fiber cores are measured. The optical fiber core wire 120 that is no longer used is identified from the lines. Discrimination of unused lines is performed, for example, with a closure tray that houses a plurality of optical fiber cores and is installed outdoors (such as on a utility pole).

  Here, the light source for discrimination 102 includes communication light blocking means for blocking downstream communication light (not shown), and communication light is incident on the light source for discrimination 102 and the output of the light source for discrimination is unstable. Is prevented. The communication light blocking means is not particularly limited, and a method such as a general-purpose optical filter or FBG (Fiber Bragg Grating) can be used.

The discriminating light preferably has a wavelength longer than 1550 nm in order to suppress interference with communication light and increase the amount of discriminating light leaked by the discriminating unit, and is shorter than 1650 nm in which the sensitivity of the light receiving element of the discriminator 104 starts to deteriorate. Wavelength is preferred. Therefore, it is necessary that the wavelength of the discrimination light is 1550 nm or more and 1650 nm or less and that the wavelength is particularly shorter than the wavelength band reflected by the monitoring light reflection filter 103.

Further, when a filter that reflects monitoring light incident from the OLT side is used, the wavelength of the discrimination light needs to be different from the wavelength band reflected by the monitoring light reflection filter.

FIG. 2 is a schematic diagram showing an aspect of a discriminator in the optical fiber discriminating apparatus of the present invention. As shown in FIG. 2, the discriminator 104 in the optical fiber identification device of the present invention includes a bent fixing portion 140 that fixes a predetermined range of the optical fiber core wire 120 by bending it into a substantially arc shape, and the bent fixing portion 140. And a light receiving element 142 disposed in the vicinity.

  One light receiving element 142 may be provided, and two or more light receiving elements 142 may be arranged according to the intensity of the discrimination light 44 or the intensity of the downlink communication light 40.

FIG. 3 is a schematic view showing another aspect of the discriminator in the optical fiber discriminating apparatus of the present invention. As shown in FIG. 3, the bend fixing portion 140 has the above-described substantially arc shape with a constant curvature, and two or more light receiving elements 142 are arranged on the object with respect to the center line 150 of the bend fixing portion. preferable.

FIG. 1 is a schematic diagram showing an entire PDS communication system and an optical core discriminating apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing an aspect of a discriminator in the optical fiber discriminating apparatus of the present invention. FIG. 3 is a schematic view showing another aspect of the discriminator in the optical fiber discriminating apparatus of the present invention. FIG. 4 is a schematic diagram of a conventional communication system for monitoring an optical fiber core wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical PDS communication system 3, 30 Optical splitter 10 Transmission apparatus (OLT)
20 Slave unit (ONU)
20-1 to 20-8 Reflective filter 40 Downstream signal light 42 Upstream signal light 44 Discrimination light 100 Optical fiber discriminating device 102 Discrimination light source 103 Filter 104 Discriminator 120 Optical fiber core wire 130 ONU side end portion 140 Bend fixing portion 142 Light receiving element 150 Center line of bending fixing part

Claims (5)

An optical fiber determination device that determines whether an optical fiber core selected from a plurality of branch optical fibers connected to an optical branch is a desired branch optical fiber,
A light source for discrimination from which discrimination light having a wavelength longer than 1550 nm and shorter than 1650 nm is incident from an end of the desired optical fiber;
An optical core discriminating apparatus comprising: a discriminator for measuring leakage of the discriminating light in a discriminating unit between the branch portion of the optical fiber and the end portion. 2. The optical fiber identification device according to claim 1, wherein the light source for determination includes a light blocking unit that blocks light having a wavelength of 1550 nm or less. The discriminator includes a bending fixing portion that bends and fixes a predetermined range of the discrimination portion of the optical fiber core wire into a substantially arc shape;
3. The optical fiber identification device according to claim 1, further comprising at least one light receiving element arranged in the vicinity of the bent fixing portion. In an optical fiber identification method for determining a desired optical fiber from a plurality of optical fibers used in an optical multi-branch communication system,
Discrimination light having a wavelength longer than 1550 nm and shorter than 1650 nm is incident from the subscriber side end of the desired optical fiber core wire,
A discriminating unit between the optical fiber branching unit and the subscriber-side end portion discriminates a desired optical fiber core from the plurality of optical fiber cores by measuring the leakage of the discrimination light with a discriminator. A method for discriminating an optical fiber from the optical fiber.   5. The optical fiber identification method according to claim 4, wherein a predetermined range of the optical fiber is bent into a substantially arc shape to provide a bent portion, and light leaked at the bent portion is measured by a light receiving element.

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