JP2009204662A - Optical cable connecting closure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable connecting closure including a photo detection means for simply and visually discriminating between an active line and a free line and usage of signal light without a special measuring device for an optical fiber conductor in the closure, and efficiently performing drawdown work for an optical cable in a short time. <P>SOLUTION: This optical cable connecting closure 22 for connection and branching to an optical cable 20 is loaded with a photo detection connector 1a including an optical branching device for branching signal light, a wavelength filter for transmitting and reflecting a predetermined wavelength of a branching signal light, a photo detecting element for receiving the signal light transmitted and reflected through the wavelength filter and converting the signal light to an electric signal, a detecting circuit for converting the electric signal to a predetermined driving signal, and a light emitting display element lighted or flickered to be visible according to the driving signal. An optical connector 26 in an optical transmission line is optically removably connected to the above photo detection connector 1a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical cable connection closure used for branching an optical fiber from a trunk optical cable and connecting a drop optical cable or the like.

  With the progress of optical communication technology, introduction of a PON (Passive Optical Network) system of a subscriber communication network represented by FTTH (Fiber To The Home) is progressing. In this PON system, in order to realize a high-speed service at the same price as a metal cable, the number of optical fibers is reduced and two-way data communication between the station side and the subscriber side is performed using one optical fiber. Single-fiber bidirectional communication systems (1.31 μm band and 1.49 μm band) have been proposed. In recent years, in addition to this, a one-core three-wave system including a broadcast signal such as video (1.55 μm band) or a two-core three-wave system has been adopted.

  In this FTTH, a method is usually used in which an overhead trunk optical cable is pulled down to a subscriber's house or the like via a connection box called a closure. For example, an optical cable called a drop optical cable is often used to drop the optical cable. However, when the optical cable is drawn from an imaginary trunk optical cable, the work environment such as on a power pole or bucket car is poor. In many situations, the cable is cut into a predetermined length, the optical fiber core wire is taken out from the cable, and the fusion splicing between the optical fibers and the reinforcing process are not easy and take time. In addition, the fusion splicing work requires a certain level of skill, and there is a problem that it is difficult to secure a working engineer for an increase in demand.

  For this reason, when the optical cable is pulled down, an optical fiber is branched from the trunk optical cable, and an optical connector is attached to the branched optical fiber in advance. Until an optical connector is attached to this branching optical fiber, it is performed by a skilled worker with skill. Then, the work after the optical connector attached to the branch fiber can be connected only by attaching / detaching the optical connector using a drop optical cable having a predetermined length with the optical connector attached in advance. As a result, there is a laying method in which the withdrawal work in the latter half is drawn down to the subscriber premises by a normal worker who has no particular skill (for example, see Patent Document 1).

Further, when optical connection or change of connection between the station side and the subscriber's home side is performed, it is necessary to perform core line discrimination in order to select a core line to be connected from among a plurality of optical fibers. For this core wire discrimination, for example, by bending the optical fiber core wire partially and detecting the leaked light, the signal light in the optical transmission line is detected without using a special light source for identification. A method for discriminating a specific core wire is known (for example, see Patent Document 2).
JP 2003-177254 A JP 2004-109401 A

  The core wire discrimination by the method disclosed in Patent Document 2 is performed by bending the optical fiber core wire, and therefore can be performed by an operator who can access the branched optical fiber core wire. However, as disclosed in Patent Document 1, when an optical cable is pulled down using an optical connector, the range where the optical connector is attached from the branched portion of the optical fiber core can be touched by a person other than a specific operator. You may be restricted from doing so. In this case, an operator who performs normal withdrawal performs determination of a core wire through an optical connector (or connection adapter) attached to a branch end in the closure.

  Assuming that 1.49 μm or 1.55 μm signal light is sent to the branched optical fiber core wire, these signal lights are in the infrared light region, so a transmission or shielding filter is used. Even if it can be taken out, it cannot be confirmed visually. Therefore, it cannot be confirmed to which of the plurality of optical connectors respectively attached to the end portions of the branched optical fiber the drop optical cable should be connected.

  For this reason, the signal light is taken out through a transmission, shielding filter, etc., and the output power of the signal light is measured (confirmed numerically) with a power meter, for example, and the invalid line (empty line) and usable line (working line) It was necessary to visually confirm the use of the signal light (1.55 μm for broadcasting or 1.49 μm for data communication). However, this requires a dedicated measuring instrument such as a power meter, and it is necessary to judge the measured value, and it will be necessary to withdraw by an operator with appropriate expertise. I couldn't make full use of the simple withdrawal work.

  The present invention has been made in view of the above-described circumstances, and it is possible to easily distinguish between an active line and an empty line and to use a signal light without using a special measuring instrument for an optical fiber core in a closure. It is an object of the present invention to provide an optical cable connection closure equipped with a light detection means that can be visually discriminated and can efficiently carry out an optical cable pull-out operation in a short time.

  An optical cable connection closure according to the present invention is an optical cable connection closure for connecting and branching an optical cable, an optical branching device for branching signal light, and a wavelength filter that transmits and reflects a predetermined wavelength of the branched signal light. , A light receiving element that receives and converts the signal light transmitted and reflected through the wavelength filter and converts it into an electrical signal, a detection circuit that converts the electrical signal into a predetermined drive signal, and a light emitting display element that is lit or blinks in a visible manner by the drive signal And an optical connector in the optical transmission path is detachably connected to the optical detection connector.

  The wavelength filter of the optical detection connector used in the present invention is a dielectric multilayer filter that transmits and reflects a plurality of signal lights having different wavelengths, and individually detects the plurality of signal lights. In addition, another optical branching device that branches the signal light from the output side is mounted on the through-side waveguide that is not guided to the detection circuit of the branching device, and the output is provided on the branching waveguide side of the other branching device. A wavelength filter that transmits signal light from the side, a light receiving element that detects the signal light, a detection circuit, and a light-emitting display element may be provided so that the signal light from the output side can also be detected.

  According to the present invention, when the light emitting display element of the light detection connector connected to the branch optical fiber in the closure is turned on or blinked, whether the connected branch optical fiber and its transmission line are a free line or a working line. In the case of a working line, the wavelength of the signal light can be identified. While looking at this display state, the user can simply and accurately pull out the optical connector attached to the optical cable for pulling out into the connector portion of the predetermined optical detection connector.

  The optical detection connector mounted in the optical cable connection closure of the present invention is connected to the optical connector attached to the end of the branched optical fiber (or directly to the end of the branched optical fiber. The optical detection connector displays the presence / absence of signal light (or optical signal) transmitted into the branch optical fiber, or displays the wavelength of the signal light, and connects the optical cable for withdrawal. Tell the operator which branch fiber to connect to.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a schematic diagram illustrating an example of a light detection connector used in the present invention, and FIG. 1B is a schematic diagram illustrating an example of a detection circuit. In the figure, 1a is a light detection connector, 2a and 2b are connector parts, 3a is a main body part, 4a is a wavelength filter, 5a and 5b are light detection devices, 6 is a light receiving element (PD), 7 is a detection circuit, and 7a is amplification. , 7b is a drive unit, 7c is a control unit, 7d is a power supply unit, 8a and 8b are light emitting display elements (LEDs), 9a is an optical branching device, 10a is a through waveguide, and 10b is a branching waveguide.

  The light detection connector 1a shown in FIG. 1A includes an input-side connector portion 2a, an output-side connector portion 2b, and a main body portion 3a. The connector portions 2a and 2b are shown as examples of receptacle-type optical connectors, but plug-type optical connectors can also be used. However, usually, the optical connector attached to the optical fiber side is often a plug type, and the connector adapters 2a and 2b are of the receptacle type, so that a connection adapter can be dispensed with. The main body 3a branches the optical signal guided from the input-side connector 2a by an optical branching device 9a having a through waveguide 10a and a branching waveguide 10b. The branching ratio of the optical branching device 9a is, for example, 1:99, 1 is branched to the branching waveguide 10b side, and 99 is branched to the through waveguide 10a.

  The optical detection connector 1a can transmit an optical signal to a subscriber's house or the like in an in-line state where the optical signal is detected by connecting to the optical transmission line, and most of the optical signal is transmitted through the through waveguide 10a. It is possible to transmit to the subscriber's home via the optical connector 2b. In this case, the optical connector 2b is connected to an optical connector attached to one end of a drop optical cable drawn to a subscriber's house or the like, and can transmit two signal lights of 1.49 μm and 1.55 μm.

A small amount of signal light branched to the branching waveguide 10b side by the optical branching device 9a transmits only the signal light having a predetermined wavelength through the wavelength filter 4a and enters the photodetector 5a, and the signal light having the reflected wavelength is transmitted. It inputs into the photon detection apparatus 5b.
As the wavelength filter 4a, for example, a wavelength filter made of a dielectric multilayer film can be used. When the received light signal includes two signal lights of 1.49 μm and 1.55 μm, one signal is used. Light (for example, 1.49 μm) is transmitted, and the other signal light (for example, 1.55 μm) is reflected. The transmitted 1.49 μm signal light is detected by turning on or blinking the red LED 8a in the light detection device 5a, and the reflected 1.55 μm signal light is turned on in the green LED 8b by the light detection device 5b. Or it is detected by blinking.

  The light detection devices 5a and 5b receive a signal light transmitted through the wavelength filter 4a and convert the light signal into an electric signal (for example, a photodiode, hereinafter referred to as PD), and an electric signal from the light receiving element 6. And a light emitting display element 8a, 8b (for example, a light emitting diode, hereinafter referred to as LED) for visually displaying the detection signal. The photodetectors 5a and 5b can be formed by, for example, a detection circuit as schematically shown in FIG. The signal light transmitted through the wavelength filter 4a is received by the PD 6 and converted into an electric signal. The electric signal is amplified to a predetermined level by the amplifying unit 7a and input to the driving unit 7b. In the drive unit 7b, a drive signal for causing the LEDs 8a and 8b to light up or blink is generated by the control unit 7c. The detection circuit 7 includes a power supply unit 7d for supplying a bias voltage for the PD 6 or the LED.

  FIG. 2 is a diagram for explaining another embodiment. In the figure, 1b is a light detection connector, 3b is a main body, 4b is a wavelength filter, 5c is a light detection device, 8c is an orange LED, 9b is an optical branching device, and 10c is a branching waveguide. Description of other reference numerals is omitted by using the same reference numerals as those used in FIG.

  The light detection connector 1b shown in FIG. 2 includes a main body portion 3b and receptacle-type connector portions 2a and 2b arranged on both the input and output sides, as in the example of FIG. The main body 3b branches the optical signal guided from the input-side connector 2b by the optical splitter 9a. The optical branching unit 9a is configured to branch the optical signal guided from the optical connector 2a by setting the branching ratio of the optical branching unit 9a to 1:99, for example, as in the example of FIG. 99 is branched into the through waveguide 10a on the waveguide 10b side. Therefore, an almost optical signal is passed through the output-side connector portion 2b by the through waveguide 10a, and a small amount of branched signal light is input to the wavelength filter 4a through the branch waveguide 10b.

  As the wavelength filter 4a, for example, a wavelength filter made of a dielectric multilayer film similar to the example of FIG. 1A is used, and the received light signal includes two signal lights of 1.49 μm and 1.55 μm. If it is, one signal light (for example, 1.49 μm) is transmitted and the other signal light (for example, 1.55 μm) is reflected. The transmitted 1.49 μm signal light is detected by turning on or blinking the red LED 8a by the light detection device 5a, and the reflected 1.55 μm signal light is turned on or off by the light detection device 5b. Detect by blinking.

  In the example of FIG. 2, when an optical cable to be pulled down by a subscriber or the like is connected to the optical connector 2b on the output side, an optical signal is transmitted from the through waveguide 10a and also from the direction of the subscriber side by bidirectional communication. There are cases where signal lights having different wavelengths are transmitted. In the one-core three-wave bidirectional communication, for example, an optical signal in the 1.31 μm band can be transmitted from the subscriber side to the station side. For this reason, the terminal on the subscriber side is detected by detecting the signal light in the 1.31 μm band transmitted from the optical connector 2b on the output side toward the optical connector 2b on the input side using the optical detection connector 1b. It is possible to detect the usage status, line status, failure detection, etc.

  This signal light is detected by connecting an optical branching unit 9b having a branching ratio of 1:99 similar to that of the optical branching unit 9a to the through waveguide 10a, and detecting light through the wavelength filter 4b on the branching waveguide 10c side. Connect the device 5c. As the wavelength filter 4b, as in the example of FIG. 1A, for example, a wavelength filter made of a dielectric multilayer film can be used. For example, only signal light having a wavelength of 1.31 μm band is transmitted. I will let you. For detection of the signal light, the light detection device 5c is formed by a detection circuit having the same configuration as that of 5a and 5b, and for example, turns on or blinks the orange LED 8c.

  3 and 4 are diagrams for explaining a configuration example of an optical cable connection closure according to the present invention. In the figure, 20 is a trunk optical cable, 20a is a sheath removal part, 21 is a branch optical fiber, 22 is a closure, 23 is a clamp part, 24 is an optical fiber branch area, 25 is a drop area, 26 is an optical connector on the drop optical cable side, Reference numeral 27 denotes a drop optical cable. Description of other reference numerals is omitted by using the same reference numerals as those used in FIGS.

  FIG. 3 is a diagram for explaining a configuration example of a closure using the light detection connector 1a described in FIG. 1A, and an example in which the working line of the branch optical fiber 21 branched from the trunk optical cable 20 and its wavelength are discriminated. It is. The branch optical fiber 21 is pulled out by using, for example, a closure 22 attached to a coating removal portion 20a at a predetermined position of the trunk optical cable 20 by a clamp means 23. The branched optical fiber 21 is terminated by inserting an optical connector (not shown) attached to the end of the fiber into the optical detection connector 1a.

  Since the light detection connector 1a is formed of a receptacle-type connector, the light detection connector 1a also serves as a connection adapter. For example, a plurality of light detection connectors 1a are arranged in the vertical direction at an intermediate position of the closure 22. Until the branch optical fiber 21 is terminated by the optical detection connector 1a in the optical fiber branch region 24 on the left side surrounded by the dotted line in the closure 22 where the optical detection connector 1a is disposed, it is carried out by an operator having specific skills. Is done. And this optical fiber branch area | region 24 may be obstruct | occluded so that it may not be damaged by another operator.

  The right withdrawal area 25 in the closure 22 is an area for dropping the drop optical cable to the subscriber's house. In the closure where the connection adapter is provided, the optical connector previously attached to the end of the drop optical cable is connected to the connection adapter. It can be installed by an operator who does not have skills. However, since the optical signal in the branch optical fiber 21 has a wavelength in the infrared region, when a normal connection adapter is used, it cannot be visually confirmed even when viewed from the opening. Therefore, it is impossible to determine which connection adapter should be connected to the drop optical cable drawn to the subscriber's home.

  However, in the present invention, the light detection connector 1a is arranged at an intermediate position in the closure 22 in place of a normal connection adapter. As a result, the signal light branched to the branching waveguide side of the signal light of the branch optical fiber 21 is terminated by the light detection connector 1a, and the presence or absence of the signal light transmitted to the branch optical fiber 21, and the signal light Can be distinguished.

  For example, if 1.49 μm signal light is transmitted to the branch optical fiber 21, the red LED display portion (8a) of the light detection connector 1a is turned on. If 1.55 μm signal light is transmitted to the branch optical fiber 21, the green LED display portion (8b) of the light detection connector 1a is turned on. If both 1.49 μm and 1.55 μm signal lights are transmitted to the branch optical fiber 21, both the red LED display portion (8a) and the green LED display portion (8b) of the light detection connector 1a Lights up. If these signal lights are not transmitted to the branch optical fiber 21, none of the LED display portions of the light detection connector 1a is lit.

  While observing the lighting state of the LED display portion of the light detection connector 1a, the optical connector 26 attached to the end of the drop optical cable 27 is inserted into the connector portion of the light detection connector 1a where a predetermined LED is lit. be able to. As a result, even the operator who has no particular skill can definitely connect the drop optical cable 27 to the connector portion of the predetermined optical detection connector. Further, since the LED display is lit even after the drop optical cable is connected, the connection check can be ensured. After the connection is completed, the LED display power supply (battery) may be left until it is exhausted, or an operation means for cutting the power supply circuit may be provided.

  FIG. 4 is a diagram illustrating a configuration example of a closure using the light detection connector 1b described in FIG. In this configuration example, as in the case of FIG. 3, the light detection connector 1b has a shape in which the connector portion is formed of a receptacle-type connector and also serves as a connection adapter. Therefore, similarly to the configuration example of FIG. 3, the branch optical fiber 21 is terminated by the light detection connector 1b, and the presence / absence of the signal light transmitted to the branch optical fiber 21 and the wavelength of the signal light can be determined. When the drop optical cable 27 is connected to the subscriber's home, the upstream signal light (1.31 μm) can be detected in the same manner.

  That is, if 1.49 μm signal light is transmitted to the branch optical fiber 21 and 1.31 signal light is transmitted from the subscriber side, the red and orange LED display portions (8a, 8c) of the light detection connector 1b are transmitted. ) Lights up. If 1.49 μm signal light is transmitted to the branch optical fiber 21 and 1.31 signal light is not transmitted from the subscriber side, only the red LED display section (8a) is lit, and the orange LED display section ( 8c) is not lit, and it can be determined that there may be some trouble on the subscriber side. If 1.55 μm signal light is transmitted to the branch optical fiber 21, the green LED display portion (8b) of the light detection connector 1b is turned on, and in the communication method in which there is no transmission from the subscriber side, it is orange. The LED display section (8c) of the LED does not light up.

  If both 1.49 μm and 1.55 μm signal lights are transmitted to the branch optical fiber 21 and 1.31 signal light is transmitted from the subscriber side, the red, green and orange colors of the light detection connector 1 b are transmitted. All of the LED display sections (8a, 8b, 8c) are turned on. In this case, if any trouble occurs on the subscriber side, the orange LED display section (8c) does not light up. Further, if these signal lights are not transmitted to the branch optical fiber 21, none of the LED display portions of the light detection connector 1b is lit as an empty core wire.

  While observing the lighting state of the LED display portion of the light detection connector 1b, the light detection connector in which a predetermined LED is turned on is connected to the optical connector 26 attached to the end of the drop light cable 27 in the same manner as in the configuration example of FIG. Insert into the connector portion 1b. As a result, even a worker who has no particular skill can definitely connect the drop optical cable to the connector portion of the predetermined optical detection connector. Further, after the drop optical cable is connected, the signal light from the subscriber side can be detected, and the use of the subscriber terminal and the check of the failure state can be performed.

It is a figure explaining the outline of the photon detection connector used by this invention. It is a figure explaining the outline of the other photon detection connector used by this invention. It is a figure explaining embodiment by this invention. It is a figure explaining other embodiment by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b ... Photodetection connector, 2a, 2b ... Connector part, 3a, 3b ... Main-body part, 4a, 4b ... Wavelength filter, 5a-5c ... Photodetection device, 6 ... Light receiving element (PD), 7 ... Detection circuit, 7a ... amplifying unit, 7b ... driving unit, 7c ... control unit, 7d ... power supply unit, 8a to 8c ... light emitting display elements (LEDs), 9a, 9b ... light splitter, 10a ... through waveguide, 10b, 10c branching guide Waveguide, 20 ... trunk optical cable, 20a ... sheath removal part, 21 ... branch optical fiber, 22 ... closure, 23 ... clamp part, 24 ... optical fiber branch area, 25 ... pull-out area, 26 ... optical connector on the drop optical cable side, 27 ... drop optical cable.

Claims (3)

  An optical cable connection closure for connecting and branching an optical cable, an optical branching device for branching signal light, a wavelength filter for transmitting and reflecting a predetermined wavelength of the branched signal light, and transmitting and reflecting the wavelength filter A light detection connector comprising: a light receiving element that receives signal light and converts it into an electrical signal; a detection circuit that converts the electrical signal into a predetermined drive signal; and a light emitting display element that is lit or blinking in a visible manner by the drive signal. An optical cable connection closure, wherein the optical connector in the optical transmission path is detachably connected to the optical detection connector.   2. The optical cable connection closure according to claim 1, wherein the wavelength filter is a dielectric multilayer filter that transmits and reflects a plurality of signal lights having different wavelengths, and detects the plurality of signal lights individually.   Another optical branching device that branches the signal light from the output side is mounted on the through-side waveguide that is not guided to the detection circuit of the branching device, and the output is provided on the branching waveguide side of the other branching device. The optical cable connection closure according to claim 1, further comprising: a wavelength filter that transmits signal light from the side; a light receiving element that detects the signal light; a detection circuit; and a light emitting display element.

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