JPH06160679A - Optical cable and its production - Google Patents

Abstract

PURPOSE:To provide the cable which suppresses the microbends generated in coated fiber ribbons when the cable is bent and is stable in transmission characteristics by providing the upper part of the coated fiber tapes with intervening layers consisting of plastic tapes or cushion tapes bent to a U shape. CONSTITUTION:The coated fiber tapes 3 housed in grooves 2 are provided with intervening layers 7-1 consisting of the plastic tapes or cushion tapes in the upper parts thereof. The width of the tape-shaped intervening layers 7-1 is set at the same width as the width of the coated fiber tapes 3 to provide large clearances in the grooves, by which the movement of the laminated and coated fiber tapes 3 inclusive of the tape-shaped intervening layers 7-1 in the grooves is facilitated. Further, glass fibers are embedded into these tapes to match the coefft. of linear expansion with the coefft. of linear expansion of the coated fiber tapes, by which the cable having the stable temp. characteristics is obtd. The tape-shaped intervening layers 7-1 prevent the local sagging of the coated fiber tapes and the contact thereof with the inside walls of the grooves and retaining winding tapes when the cable is bent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable having a high density of optical fibers housed in a groove of a spacer and a manufacturing method.

[0002]

2. Description of the Related Art As an optical cable for constructing an optical communication network, there is a structure in which an optical fiber is housed in a groove of a spacer in which a spiral groove is provided in a linear member having a circular cross section. As shown in FIG. 4, as an optical cable of this type, a plurality of optical fibers are arranged, and a tape core wire 3 covering the optical fibers is housed in a groove 2 of a spacer 1 to form an optical unit 4. There is a structure in which the polymer is polymerized around the strength member 5 and a plastic sheath 6 is applied on the strength member 5. (JP-A-4
No. 143710). Its features are that the optical fibers can be housed at a high density, and because the optical fibers are housed in the groove, they are mechanically stable and highly reliable.

[0003]

Such an optical cable usually also has excellent characteristics, but when it is bent, the tape core wire is locally compressed or pulled,
In order to deal with this, the laminated tape cores may float from the bottom of the groove, and as a result, both edges of the tape core may come into contact with the wall surface of the groove or the winding tape, resulting in microbends in this part. It was Therefore, it is an object of the present invention to provide an optical cable and a method for manufacturing the same that solve the above problems.

[0004]

DISCLOSURE OF THE INVENTION The present invention is an optical cable formed by accommodating a tape core wire in a groove of a spacer having a spiral groove on the surface of a filament body, wherein an optical cable is formed above the tape core wire. An optical cable provided with an intervening layer.

The present invention is also an optical cable in which the intervening layer is a plastic tape or a C-shaped cushioning tape.

Further, the present invention is a method of manufacturing an optical cable in which a tape core wire is housed in a groove of a spacer having a spiral groove on the surface of a filament, in which the cushioning intervening tape is bent in a U-shape. And a U-shaped cushioning tape is provided on the tape core wire.

[0007]

According to the above construction, the tape core wire housed in the groove is provided with the intervening layer made of plastic tape or cushioning tape on the upper portion thereof. On the other hand, when the cable is bent, the tape core wire in the groove causes a local slack, and the tape core wire moves in the outer circumferential direction of the groove to absorb the slack. At this time, in particular, the edge of the upper tape core may come into contact with the inner wall of the groove or the winding tape to cause a microbend. In addition, since micro-bends are formed in the overlapping portion of the push-up tape, micro bends are added.

The tape-shaped intervening layer of the present invention does not cause microbending because it makes a planar contact with the tape core wire.
Further, the cushioning intervening layer of the present invention is for preventing the core wire of the tape from coming into contact with the inner wall of the groove and for alleviating the force.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. An embodiment according to the present invention will be described based on FIGS. 1 to 3. FIG. 1 is a cross-sectional view showing the structure of this embodiment, in which 1 is a spacer having a groove 2 with a width of 1.8 mm and a depth of 3 mm spirally formed on a plastic filament having an outer diameter of 5 mm, and 3 is a 4-core single core. The mode fiber is made of UV curable resin and has a width of 1.1 mm and a thickness of 0.1 mm.
A tape core wire 4 formed in 4 mm contains three tape core wires in the groove 2 and a tape-shaped intervening layer 7-1 on the tape core wire, and a push-winding tape 8 is wound around it in half. The optical unit 5 is a steel wire, and 6 is a plastic sheath having an outer diameter of 18 mm. The intervening layer 7-1 has substantially the same size as the tape core wire 3 and is a tape made of a thermoplastic resin such as nylon, polyester, or polyethylene, or an ultraviolet curable resin such as an acrylic resin. The width of the tape-shaped intervening layer is made the same as the width of the tape core wire in order to facilitate the movement of the laminated tape core wire including the tape-shaped intervening layer in the groove by taking a large clearance in the groove. The degree of freedom is increased assuming that stress is applied to the tape core wire. Further, by embedding a glass fiber in these tapes and matching the linear expansion coefficient with the tape core wire, a cable with stable temperature characteristics can be obtained. These tape-shaped intervening layers 7-1 are for preventing the cables from being bent and causing the tape core wire to locally sag and contact the inner wall of the groove and the winding tape.

FIG. 2 is a sectional view showing another structure of the present embodiment. Instead of the tape-shaped intervening layer 7-1 of FIG. 1, a cushioning tape is bent in a U-shape to form an intervening layer 7-2.
Is applied, and other configurations are the same as those in FIG. As the cushioning intervening layer 7-2, a tape having an upper surface coated with a water-absorbing swelling substance has a width of 3.5 mm and a thickness of 0.2 mm.
When the three tape core wires 3 were introduced into the groove 2 by using the non-woven fabric of No. 3, both ends were bent by 1 mm, formed into a U shape, and inserted into the groove. By providing a cushioning intervening layer,
This is because when the cable is bent, it is possible to absorb the occurrence of microbends caused by the contact of the upper core wire with the inner surface of the groove or the winding tape. Furthermore, by applying a swelling substance to this intervening layer, it is possible to prevent water spilling when the cable is flooded. Usually, as the cushioning intervening layer, a fibrous material having a space inside, such as foamed plastic, elastomer, or non-woven fabric, is used.

Examples of the water-swelling substance forming the water-swelling substance layer include starch, a hydrolyzate of an acrylonitrile graft polymer, a neutralized product of a starch-acrylonitrile acid graft polymer, and a hydrolyzate of a vinyl acetate-acrylic acid ester copolymer. Examples thereof include hydrolyzed products, hydrolyzed products of these crosslinked products or acrylamide copolymers, crosslinked products thereof, polyacrylic acid salt crosslinked products, and isobutylene-maleic anhydride copolymer crosslinked products.

FIG. 3 is a cross-sectional view showing a third structure of this embodiment. Instead of the spacer 1 of FIG. 2, a spacer having four spiral grooves on the surface of one filament is used. It is the used cable. Other configurations are the same as those in FIG. Figure 1
Also, the cable of this embodiment shown in FIG. 2 and the conventional cable shown in FIG.
Wrap it around and change the transmission loss before and after that by 1.55μ wavelength.
It was measured for m. As a result, no change was found in the transmission loss of the cable according to the present invention, but in the conventional cable, 0.1 dB /
An increase in km was observed.

[0013]

As described above in detail, according to the present invention, by providing the intervening layer of the plastic tape or the U-shaped cushioning tape on the upper portion of the tape core wire housed in the groove, It is possible to suppress the microbend that occurs in the tape core wire when the cable is bent, and to obtain a cable that is stable in terms of transmission characteristics. Further, since the above-mentioned U-shaped cushion tape can be supplied while bending the flat tape into a U-shape, it can be manufactured without requiring a special device or an additional step.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of this embodiment.

2 is the same as FIG.

FIG. 3 is the same as FIG.

FIG. 4 is a cross-sectional view showing a conventional cable configuration.

[Explanation of symbols]

 1: Spacer 2: Groove 3: Tape core wire 4: Optical unit 5: Low tension member 6: Sheath 7, 7-1, 7-2: Intervening layer 8: Pressing tape

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shigeru Tanaka 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Shigeru Tomita 1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. An optical cable formed by accommodating a tape core wire in a groove of a spacer having a spiral groove on the surface of a filament body, wherein an intervening layer is provided above the tape core wire. And optical fiber cable. 2. The optical cable according to claim 1, wherein the intervening layer is a plastic tape or a C-shaped cushioning tape. 3. A method of manufacturing an optical cable in which a tape core wire is housed in a groove of a spacer having a spiral groove on the surface of a filament, wherein a cushioning intervening tape is introduced into the groove while being bent in a U-shape. A method for manufacturing an optical cable, wherein a U-shaped cushioning tape is provided on the tape core wire.