JP2001052540A - Optical fiber composite overhead ground wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost optical fiber composite overhead ground wire without expensive materials such as aluminum used in the spacer type. SOLUTION: This optical fiber composite overhead ground wire has an optical fiber unit 10 including an optical fiber stored in a protection tube 12, and multiple conducive element wires 13 twisted over the outer peripheral surface of the protection tube 12. The optical fiber unit 10 comprises a laminate 18 laminating multiple stages of optical fiber tape coated fiber 16 made by cladding multiple optical fiber coated fibers 15 with a covered layer 19 made of heat resistant resin, and a buffer layer 17 covering the outer peripheral surface of the laminate 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber composite ground wire, and more particularly to an optical fiber composite ground wire having a structure containing an optical fiber unit composed of a plurality of optical fiber wires.

[0002]

2. Description of the Related Art An optical fiber unit (hereinafter, referred to as an "OP unit") formed by twisting a plurality of optical fiber strands with an overhead ground wire for lightning protection. Fiber composite overhead ground wire (hereinafter, "OPG
W ". ) Is generally known.

[0003] In particular, a structure provided with a spacer formed with a gap for accommodating an OP unit is generally called a spacer type OPGW.

[0004] Among the spacer-type OPGWs, as a well-known technology for multi-cores, which is increasingly required with the further development of the highly information-oriented society, the OP unit has been developed.
Spacer type OP using single-core optical fiber ribbon
There is a GW.

A conventional spacer type O corresponding to the multi-core
The PGW is shown in FIGS.

[0006] As shown in FIG.
The GW is mainly composed of an OP unit 1, a protection tube 2 made of an aluminum pipe containing the OP unit 1, and an overhead ground wire portion 4 made of a plurality of aluminum-coated steel wires 3 twisted on the protection tube 2. ing.

[0007] As shown in FIG. 5, the OP unit 1 comprises an optical fiber tape core 6 having four optical fibers 5 arranged in a plane and having a resin coating on the periphery thereof. It is accommodated in each gap, and a holding roll 8 is wound around the outer periphery of the spacer 7.

[0008]

The spacer 7 provided in this spacer type OPGW is formed of an aluminum alloy for reasons of workability and handling.

However, the conventional spacer type OPGW
However, there is a problem that a large amount of an aluminum alloy is required as a material of the spacer 7 and the cost of the OPGW increases because the price of the aluminum alloy is high.

[0010] Actually, other than the spacer type OPGW,
As a PGW, a sponge-type OPGW in which an optical fiber is twisted around a cylindrical sponge, or a slip-type OPGW
Since GW is used for general purposes, OP
The GW need not be of the spacer type.

SUMMARY OF THE INVENTION An object of the present invention is to provide a low cost optical fiber composite ground wire which does not use an expensive material such as aluminum unlike a spacer type.

[0012]

According to a first aspect of the present invention, an optical fiber unit having an optical fiber is accommodated in a protective tube, and a plurality of conductor strands are provided on the outer periphery of the protective tube. In the twisted optical fiber composite overhead ground wire, the optical fiber unit is a laminated body in which a plurality of optical fiber ribbons in which a plurality of optical fiber strands are covered with a coating layer made of a heat-resistant resin are laminated in a plurality of stages, And a buffer layer covering the outer periphery of the laminate.

According to a second aspect of the present invention, the buffer layer is Kevlar,
It consists of a glass fiber bundle or a glass tape.

According to a third aspect of the present invention, the laminate is twisted to obtain an extra length.

According to a fourth aspect of the present invention, in the buffer layer, a cushioning material is spirally wound around the outer periphery of the laminate.

According to the configuration of the first aspect, the pressure and impact from the outside are alleviated by the coating layer and the buffer layer in each optical fiber, and the transmission loss does not become larger than a predetermined value.

According to the second aspect of the present invention, since the OP unit is composed of the optical fiber ribbon and the low-cost buffer layer, the cost of the OPGW can be reduced.

According to the third aspect of the present invention, since the laminate has an extra length, it can be freely expanded and contracted even if the OPGW is bent, and the pressure on the optical fiber can be tolerated.

According to the structure of the fourth aspect, the torsion of the laminate is stably maintained.

[0020]

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an OPGW according to the present invention.

As shown in FIG. 1, this OPGW is
Unit 10 and a protective tube 12 made of an aluminum pipe for accommodating the OP unit 10 to protect it from the outside.
And an overhead ground wire portion 14 composed of a plurality of aluminum-coated steel wires 13 twisted on the protection tube 12.

As shown in FIG. 2, the OP unit 10
A laminated body in which eight optical fiber wires 15 are arranged in a plane and eight bundled optical fiber tape core wires 16 having a coating layer 19 made of a heat-resistant resin provided on the periphery thereof are stacked in eight stages and twisted. The structure is such that a buffer layer 17 is formed around 18.

Although not shown, the laminated body 18 of the eight-core optical fiber tape 16 is provided in the protective tube 12 in order to give each eight-core optical fiber tape 16 an extra length as much as possible. Is given a twist of about 500 m in pitch.

The buffer layer 17 is made of a buffer material such as Kevlar (trade name of DuPont), a glass fiber bundle, or a glass tape.
Is provided so as to fill the space between the laminated body 18 and the protective tube 12 around it.

FIG. 3 is a perspective view of an OP unit showing a state in which a glass fiber bundle is used between the eight-core optical fiber ribbon 16 and the protective tube 12 using a glass fiber bundle as a cushioning material. .

As shown in FIG. 3, the glass fiber bundle 17a
Are loosely wound on the laminated body 18 of the eight-core optical fiber ribbon 16 in a spiral manner in a direction opposite to the twisting direction of the eight-core optical fiber ribbon 16.

Next, the operation will be described.

In this OPGW, since each optical fiber 15 of the OP unit 10 is covered with the coating layer 19 and the buffer layer 17, external pressure and impact are alleviated, and the transmission loss becomes smaller than a predetermined value. Does not grow. In addition, each of the eight-core optical fiber ribbons 16 is twisted and held by the buffer layer 17, so that a sufficient extra length is provided. As a result, the eight-core collective optical fiber ribbon 16 can be expanded and contracted independently and sufficiently, so that the distortion of the optical fiber 15 does not increase and the OPGW does not increase.
Transmission loss does not increase.

As described above, according to the present invention, a high transmission rate can be realized without using expensive aluminum, so that the cost of the OPGW can be reduced. Further, since the spacer is not used, the operation of housing the optical fiber ribbon in the groove of the spacer is not required, and the manufacturing becomes easy.

Next, the OPGW manufactured in this embodiment is
Will be described.

The experiment was conducted using lot No. Lot No. 1 of each of the eight-core optical fiber ribbons of Nos. 1 to 8 For each of the fiber strands 1 to 8, the transmission loss in the state of the fiber strand,
The transmission loss in the state of the OP unit and the transmission loss in the state of the OPGW were measured, and their average value, maximum value, and minimum value were calculated.

Tables 1 to 3 show the measurement results.

Table 1 shows lot No. 1 to 3 show the measurement results of the optical fiber ribbons.
o. Table 3 shows the measurement results of the optical fiber ribbons of Nos. 4 to 6; 7 shows the measurement results of the optical fiber ribbons 7 and 8, and the average value, the maximum value, and the minimum value.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

As shown in Tables 1 to 3, the OPGW according to the present invention, for example, has a transmission loss of 0.8 dB / km at a working wavelength λ = 1.30 μm specified by Tokyo Electric Power Company. Of the lot No. Lot No. 6 of the optical fiber tape ribbon of No. 6 One optical fiber becomes maximum when processed into OPGW, and the maximum value is 0.43 dB / km. This satisfies the standard well.

That is, it is understood that the present invention can sufficiently protect the optical fiber without using the conventional aluminum spacer, and can obtain a high transmission rate.

In this embodiment, a glass fiber or a tape is mentioned as one of the buffer materials of the OPGW. However, this is not limited to the use of a glass fiber bundle or a tape used as a press-winding optical fiber in a sponge type OPGW. Is different
It is used to protect the laminate of optical fiber ribbons and, as described above, retain the laminate in a twisted state to provide extra length.

[0041]

As described above, according to the present invention, it is possible to provide an OPGW having high economical effects and having no problem in performance without using expensive aluminum spacers.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an OPGW showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the OP unit of FIG.

FIG. 3 is a perspective view of the OP unit of FIG. 1;

FIG. 4 is a cross-sectional view of a conventional OPGW.

FIG. 5 is a cross-sectional view of the OP unit in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 OP unit 12 Protective tube 13 Aluminum-coated steel wire (conductor wire) 14 Overhead ground wire portion 15 Optical fiber wire 16 Optical fiber tape core 17 Buffer layer 18 Laminate 19 Coating layer

Claims (4)

[Claims] An optical fiber unit having an optical fiber is accommodated in a protective tube, and a plurality of conductor strands are twisted around an outer periphery of the protective tube. It is characterized by comprising a laminated body in which optical fiber ribbons each of which is covered with a coating layer made of a heat-resistant resin are laminated in a plurality of stages, and a buffer layer covering the outer periphery of the laminated body. Optical fiber composite overhead ground wire. 2. The optical fiber composite overhead ground wire according to claim 1, wherein said buffer layer is made of Kevlar, glass fiber bundle, or glass tape. 3. The optical fiber composite overhead ground wire according to claim 1, wherein said laminate is twisted to obtain an extra length. 4. The optical fiber composite ground wire according to claim 1, wherein said buffer layer is formed by spirally winding a buffer material around an outer periphery of said laminated body.