JP2010281966A - Optical cable, optical cable assembly, and method of detecting optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable which enables a coated optical fiber to be identified and an optical cable assembly obtained by assembling a plurality of such optical cables, and to provide a method of detecting a prescribed optical cable from the optical cable assembly. <P>SOLUTION: The optical cable 1 includes a coated optical fiber 2 with a high-tensile wire 3 arranged in one line on both sides and is covered with a black cable jacket 4, wherein a light transmitting layer 6 is disposed between the coated optical fiber 2 and the cable jacket 4. If a V-grooved notch 5 for ripping the jacket is provided on the major side of the optical cable 1, this part becomes a light leakage part A having a thin cable jacket which, with light from the coated optical fiber 2 leaking outside the optical cable 1 through the cable jacket 4 when the optical cable 1 is bent, enables the coated optical fiber to be identified. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical cable capable of contrasting cores, an aggregate optical cable in which a plurality of optical cables are aggregated, and an optical cable detection method for detecting a predetermined optical cable from the aggregate optical cable.

  With the spread of information communication networks such as the Internet, construction of optical networks is progressing in order to cope with bidirectional communication in addition to speeding up communication and increasing the amount of information. In this optical network, a FTTH (Fiber To The Home) service has been started to provide a high-speed communication service by directly connecting a communication carrier and a general home with an optical fiber. In FTTH, a predetermined optical fiber is usually branched by an optical connection box called a closure from an aggregating optical cable for aerial laying in which a large number of optical fibers are aggregated, and the branched optical fiber is said to be an optical drop cable. A method is used in which an existing optical cable is connected and pulled down to a subscriber's house or the like.

  As shown in FIG. 6, the optical wiring by the optical fiber is usually provided with a trunk optical cable 21 for a trunk line along a main road in a city from a service station such as data communication. As the trunk optical cable 21, for example, a general-purpose optical cable such as a spacer-type multi-core optical cable (for example, 100 cores or more) containing a plurality of optical fiber ribbons or the like is used. The trunk optical cable 21 is branched to a branch optical cable 22 via a first closure 24, and is laid along the subscriber's house in anticipation of future demand. The branch line optical cable 22 is an aggregate optical cable in which a plurality of optical cables are aggregated.

  As such an aggregate optical cable, when the number of optical fiber cores is relatively small, about eight optical fibers, as shown in FIG. 7, a plurality of optical cables are disposed around a central strength member 32 in which a steel wire or the like is coated with a resin. A collective optical cable 30 in which 31 (also referred to as an optical element) is twisted and supported is known (see, for example, Patent Document 1). Here, the optical cable 31 has, for example, a rectangular cross section in which tensile strength wires (tension members) 3 are arranged on both sides of the optical fiber core wire 2 and collectively covered with the cable jacket 4 as shown in FIG. It is used. The optical cable 12 shown in FIG. 10 has a V-groove notch 5 for tearing the jacket.

  In addition, for example, as shown in FIG. 8, a polyethylene pipe 33 is integrally coupled to the strength member 32 ′, a plurality of optical cables 31 are accommodated in the pipe 33 in a loose state, and an opening 34 opened in the pipe 33. A collective optical cable 30 ′ configured to take out the optical cable 31 from the cable is also known (see, for example, Patent Document 2). In addition, there is a configuration in which a plurality of optical cables 31 are bundled at a predetermined interval using a binding member or the like and are aerial supported by a spiral wire or the like.

JP 10-333000 A JP 2003-270501 A

  When an application for use of optical fiber is made, an unused optical cable 31 in the branch line optical cable 22 is connected to the optical drop cable 23 via the second closure 25 near the applicant's house (subscriber's house). And withdrawn individually to the subscriber's home. As the optical drop cable 23, for example, an optical cable similar to the optical cable 32 described in FIG. 10 is used, and this is wound around a messenger wire or suspended by a spiral wire and laid to the subscriber's home. In many cases, a self-supporting type optical drop cable having a shape in which a support line portion is provided integrally with the optical cable 32 is used.

  When pulling down from the branch line optical cable 22 using the optical drop cable 23, it is necessary to identify and specify which optical cable 32 in the branch line optical cable 22 is used. As shown in FIG. 10, the optical cable 32 of the collective optical cable 30 used as the branch line optical cable 22 is usually about 3 mm on the long side of the rectangular cross section, and the markings and characters to be printed are about 2 mm wide so that it is not easy to distinguish. Absent. In addition, since the branch line optical cable 22 is laid outside, there may be cases where the printed markings, characters, etc. cannot be distinguished due to surface contamination and rubbing due to wind and rain.

  For this reason, in order to identify a predetermined optical fiber in an optical line having a plurality of optical fibers, test light is incident from one end of the optical fiber to be compared, and the optical line is transmitted in the state of transmission of the test light. There is a method called cord contrast, in which a plurality of optical fiber cores are bent, leak light from the bent portion is detected, and a target optical fiber core wire is identified from the plurality of optical fiber core wires. FIG. 9 shows a core discriminator 40 used for detecting leaked light in such a core contrast.

  However, since optical cables and optical drop cables are used outdoors, carbon black etc. are blended in order to provide the cable jacket with weather resistance (ultraviolet light resistance), and the cable jacket is often black. It is used. And in the optical cable and optical drop cable which have such a black cable jacket, since test light cannot permeate | transmit a thick black coating | cover, there existed a problem that a core line contrast was not applicable.

  The present invention has been made in view of the above-described circumstances, and provides an optical cable capable of contrasting cores and an aggregate optical cable in which a plurality of such optical cables are aggregated, and detects a predetermined optical cable from the aggregate optical cable. An object of the present invention is to provide an optical cable detection method.

  An optical cable according to the present invention is an optical cable in which tensile strength wires are arranged in a line on both sides of an optical fiber core and covered with a black cable jacket, and transmits light between the fiber core and the cable jacket. By disposing the layers, a light leakage portion is formed in which light from the fiber core wire leaks out of the optical cable through the cable jacket when the optical cable is bent. The light leaking portion may be formed on the long side when the cross section of the optical cable is substantially rectangular, and may be formed in the notch portion when having a notch for tearing the jacket. The black cable jacket can be made of flame retardant polyethylene containing carbon black, and the light transmission layer can be made of flame retardant polyethylene containing no carbon black.

  Furthermore, the collective optical cable according to the present invention is configured by bundling a plurality of the optical cables. After the aggregated optical cable is laid, test light is incident on a specific optical cable in the aggregated optical cable from the start end side, and the optical cable is taken out and bent at an arbitrary position of the aggregated optical cable. A specific optical cable in the collective optical cable is detected.

  According to the present invention, since the black cable jacket at the light leaking portion is thin, the test light incident on the optical fiber core wire can be emitted from the bent portion by bending the cable, so that the core wire contrast is performed. It becomes possible. Further, by using a black cable jacket for the outer layer, it is possible to ensure the weather resistance necessary for using the cable outdoors.

It is a figure which shows an example of the optical cable by this invention. It is a figure which shows another example of the optical cable by this invention. It is a figure which shows another example of the optical cable by this invention. It is a figure which shows another example of the optical cable by this invention. It is a figure which shows an example at the time of comprising the optical cable by this invention as an optical drop cable. It is a figure for demonstrating the installation form of an optical wiring. It is a figure which shows an example of the conventional aggregated optical cable. It is a figure which shows another example of the conventional aggregated optical cable. It is a figure which shows a core wire discriminator. It is a figure which shows the conventional optical cable.

Hereinafter, preferred embodiments of the optical cable of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an example of an optical cable according to the present invention. In the figure, 1 is an optical cable, 2 is an optical fiber core wire, 3 is a tensile strength wire (tension member), 4 is a cable jacket, 5 is a V-groove notch, and 6 is a light transmission layer.

  The optical cable 1 has a rectangular cross section, and an optical fiber core 2 is arranged in the center, and tensile strength wires 3 are arranged in parallel so as to be aligned with the optical fiber core 2 on both sides of the optical cable 1. The cover 4 is covered and covered. On the long side of the optical cable 1, a V-groove notch 5 is formed for tearing the jacket for facilitating removal of the optical fiber core 2.

  Then, in this embodiment, a light transmission layer 6 is provided between the optical fiber core 2 and the cable jacket 4, and when the optical cable 1 is bent, the test from the optical fiber core 2 is performed. A light leakage portion A through which light leaks out of the optical cable 1 through the cable jacket 4 is formed.

  Here, when the optical cable 1 is bent, when the optical fiber core wire 2 and the tensile wire 3 are arranged at right angles, that is, when the cross section of the optical cable 1 is rectangular, it is preferable to bend the optical cable 1 in the direction perpendicular to the long side. The light leakage portion A is preferably provided on the long side of the optical cable 1 because it is easier than bending the short side at a right angle. In the optical cable 1 shown in FIG. 1, since the notch 5 is formed on the long side, the light leakage portion A is a portion where the notch 5 is formed.

For example, the optical cable 1 may have a short side of 1.6 mm to 2.7 mm and a long side of about 3.0 mm to 4.0 mm, and may be formed in an elliptical shape in addition to a rectangular shape.
The optical fiber 2 is a so-called optical fiber in which a glass fiber having a standard outer diameter of 125 μm is coated with a coating outer diameter of about 250 μm, or further coated on the outside (including a colored coating). It shall include all that have been subjected to.
In addition, the tensile strength wire 3 prevents the optical fiber core wire 2 from being excessively stretched, distorted, and compressive strain due to temperature changes, and also has a function of protecting the optical cable from compression and impact from the side surface of the optical cable. For the tensile strength wire 3, for example, a steel wire having an outer diameter of about 0.5 mm or FRP in which high-strength fibers are hardened with a resin is used.

The cable jacket 4 preferably has good moldability and appropriate hardness and flexibility. For example, flame retardant polyethylene is used. And in order to give a weather resistance (ultraviolet light resistance), pigments, such as carbon black, are mix | blended and formed in black.
The light transmission layer 6 can be made of flame retardant polyethylene, which is the same material as the cable jacket 4, but no pigment is added so that light from the optical fiber 2 is transmitted when the optical cable is bent. Formed with.
In the present invention, the black cable jacket includes a dark cable jacket that hardly transmits visible light or infrared light.

  For example, when the cable jacket 4 is made of flame retardant polyethylene containing 2% by weight of carbon black, and the light transmission layer 6 is made of flame retardant polyethylene to which no carbon black is added, By setting the minimum thickness d of the cover 4 to 100 μm or less, it was possible to confirm the detection of the test light (infrared light) by the cord discriminator.

  FIG. 2 is a diagram showing another example of the optical cable according to the present invention. In the figure, 1a is an optical cable, 2 is an optical fiber core wire, 3 is a tensile strength wire, 4 is a cable jacket, 6a is a light transmission layer, and each component is the same as the optical cable 1 shown in FIG. Therefore, detailed description is omitted.

  The optical cable 1a shown in FIG. 2 is different from the optical cable 1 shown in FIG. 1 because the optical cable 1a does not have the V-groove notch 5 provided in the optical cable 1, so that the light transmission layer 6a is provided near the long side of the optical cable 1a. It is a point. Also in the optical cable 1a of FIG. 2, when the cable jacket 4 is formed of flame retardant polyethylene containing 2% by weight of carbon black, and the light transmission layer 6a is formed of flame retardant polyethylene to which no carbon black is added. The minimum thickness d of the cable jacket 4 in the light leakage portion A is set to 100 μm or less.

  FIG. 3 is a view showing still another example of the optical cable according to the present invention. In the figure, 1b is an optical cable, 2 is an optical fiber core wire, 3 is a tensile strength wire, 4 is a cable jacket, 5 is a V-groove notch, 6b is a light transmission layer, and each component is shown in FIG. Since it is the same as the optical cable 1 shown, detailed description is abbreviate | omitted.

The optical cable 1b shown in FIG. 3 differs from the optical cable 1 shown in FIG. 1 in that the light transmission layer 6b is provided not only around the optical fiber core wire 2 but also around the tensile strength wire 3. By doing in this way, it becomes possible to coat | cover the optical fiber core wire 2 and the tensile strength wire 3 collectively with the resin material which comprises the light transmissive layer 6b, and can reduce the quantity of carbon black to be used.
Also in the optical cable 1b of FIG. 3, when the cable jacket 4 is formed of flame retardant polyethylene containing 2% by weight of carbon black, and the light transmission layer 6b is formed of flame retardant polyethylene not added with carbon black. The minimum thickness d of the cable jacket 4 in the light leakage portion A is set to 100 μm or less.

  FIG. 4 is a view showing still another example of the optical cable according to the present invention. In the figure, 1c is an optical cable, 2 is an optical fiber core wire, 3 is a tensile strength wire, 4 is a cable jacket, 5 is a V-groove notch, 6c is a light transmission layer, and each component is shown in FIG. Since it is the same as the optical cable 1 shown, detailed description is abbreviate | omitted.

  The optical cable 1c shown in FIG. 4 is different from the optical cable 1 shown in FIG. 1 in that a plurality of optical fiber cores 2 are provided. In the case of the optical cable 1c shown in FIG. 4, in order to select a predetermined optical cable 1c from an aggregate optical cable in which a plurality of optical cables 1c are bundled, an arbitrary one of the optical fiber cores 2 of the optical cable 1c is selected. What is necessary is just to detect the light which injects into this and injects into this and leaks from the light leak part A with a core line discriminator.

  FIG. 5 is a diagram showing an example when the optical cable according to the present invention is configured as an optical drop cable. In the figure, 1d is an optical cable, 2 is an optical fiber core wire, 3 is a tensile strength wire, 4 is a cable jacket, 5 is a V-groove notch, 6 is a light transmission layer, 7 is a steel wire, and 8 is a neck. The same components as those of the optical cable 1 shown in FIG.

An optical cable 1d shown in FIG. 5 has a main body portion 11 and a support wire portion 12, both of which are integrally formed via a narrow neck portion 8. Since the main body 11 has the same configuration as that of the optical cable 1 shown in FIG.
A steel wire 17 (outer diameter of about 1.2 mm) made of a single core wire or a stranded wire is used for the support wire portion 12 and is made of the same resin material as that of the cable jacket 4 when the cable jacket 4 of the main body 11 is formed. It is formed by batch coating. This form of cable is often used as a drop cable.

  The optical cable 1d is used as an optical drop cable when it is pulled down to the subscriber house shown in FIG. 6. For example, when a plurality of optical drop cables 23 are pulled out from one closure 25 and pulled down to each of a plurality of subscriber houses. There is. In such a case, it is necessary to select a predetermined optical drop cable from a plurality of optical drop cables. However, in the optical cable 1d according to the present invention, since the light leakage portion A is formed, it is possible to control the cores. It has become.

The optical cables (1 to 1c) configured as described above can be used as a collective optical cable by bundling a plurality of optical cables. As in the case of the assembly of the optical cables, a plurality of optical cables (1 to 1c) can be twisted and supported around the center strength member 32, as described in FIG. For example, as the central strength member 32, a steel wire having an outer diameter of 2.6 mm covered with polyethylene having an outer diameter of 5.0 mm is used, and eight optical cables are twisted together. Further, as shown in FIG. 8, a plurality of optical cables (1 to 1c) may be housed in the resin pipe 33 in a loose state.
In addition to this, a plurality of optical cables (1 to 1c) may be bundled at a predetermined interval using a binding member or the like, and supported in aerial manner with a spiral wire or the like.

Next, an example in which the above-described collective optical cable is laid using the branch optical cable 22 of the optical wiring described in FIG. 6 will be described.
A collective optical cable composed of a plurality of optical cables (1 to 1c) uses a first closure 24 to branch a predetermined number of optical fiber cores for communication from a trunk optical cable 21, and an optical connector or the like at an end thereof. Is connected. This aggregated optical cable is installed as a branch line optical cable 22 in the vicinity of the subscriber's house in anticipation of future demand.

  Then, when there is an application for the use of the optical fiber, a small second closure 25 is installed at the dropping point of the optical fiber, a predetermined optical cable in the branch line optical cable 22 is branched, and one of the optical drop cables 23 is branched to this. Are connected to the subscriber's house. As the optical drop cable 23, the optical cable 1d described above can be used, but a normal optical cable having no slit or a self-supporting optical cable can also be used.

  In the second closure 25, in order to connect the optical drop cable 23 to a predetermined optical cable in the branch line optical cable 22, it is necessary to identify and specify the optical cable in the branch line optical cable 22. For this reason, in the collective optical cable 22 in which a plurality of optical cables are assembled, the optical cable to be dropped and connected cannot be identified at the installation point of the second closure 25 by identification of markings or characters attached to the cable surface. Next, the following core line control is performed.

  First, the first closure 24 from which the branch line optical cable 22 is branched is opened, and the optical cable to be pulled down is confirmed. In the first closure 24, since the optical cable in the branch line optical cable 22 is not directly exposed to the outside air, the markings and characters attached to each optical cable can be identified. Note that a tag may be attached to the end of each optical cable in order to improve discrimination.

Next, a predetermined optical cable to be pulled down in the branch line optical cable 22 is confirmed at the first closure 24, and test light is incident on this optical cable from the start end side. In this state, at the portion of the second closure 25 at the withdrawal point, each optical cable is bent to a bending diameter at which leakage light is easy to detect, and the presence or absence of leakage light is detected to determine a predetermined optical cable. The determined optical cable is cut and branched, and the optical drop cable 8 is fused or connected to the optical cable using an optical connector.
For example, a core discriminator 40 as shown in FIG. 9 can be used for detection of the leaked light. Also, when visible light is used as the test light, it can be detected visually.

DESCRIPTION OF SYMBOLS 1 ... Optical cable, 2 ... Optical fiber core wire, 3 ... Tensile wire (tension member), 4 ... Cable jacket, 5 ... Notch, 6 ... Light transmission layer, 7 ... Steel wire, 8 ... Neck part, 11 ... Main-body part, DESCRIPTION OF SYMBOLS 12 ... Support line part, 21 ... Trunk optical cable, 22 ... Branch line optical cable, 23 ... Optical drop cable, 24 ... 1st closure, 25 ... 2nd closure, 30 ... Collective optical cable, 31 ... Optical cable, 32 ... Center strength body 33 ... pipes, 34 ... openings, 40 ... core discriminators.

Claims (8)

An optical cable in which tensile strength wires are arranged in a line on both sides of an optical fiber core and covered with a black cable jacket,
By providing a light transmission layer between the optical fiber core and the cable jacket, when the optical cable is bent, a light leakage portion where light from the fiber core leaks out of the optical cable through the cable jacket An optical cable characterized by forming   The optical cable according to claim 1, wherein a cross section of the optical cable is substantially rectangular, and the light leakage portion is provided on a long side.   The optical cable according to claim 1 or 2, wherein the optical cable has a notch for tearing the cable jacket, and the light leakage portion is provided in a portion where the notch is provided.   The black cable jacket is made of flame retardant polyethylene containing carbon black, and the light transmission layer is made of flame retardant polyethylene not containing carbon black. Optical cable.   5. The optical cable according to claim 4, wherein when the cable jacket has a carbon black content of 2 wt%, the thickness of the cable jacket of the light leakage portion is 100 μm or less.   The optical cable according to claim 1, wherein the light transmission layer is provided to the periphery of the tensile strength line.   A collective optical cable, wherein a plurality of optical cables according to claim 1 are bundled.   After the collective optical cable according to claim 7 is laid, test light is incident on a specific optical cable in the collective optical cable from a start end side, and the optical cable is taken out and bent at an arbitrary position of the collective optical cable. An optical cable detection method comprising: detecting the test light leaked to the outside by the step and detecting a specific optical cable in the aggregated optical cable.

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