JPH08327857A - Formation of branching part of multi-core optical fiber and structure of branching part - Google Patents

Abstract

PURPOSE: To make it possible to constitute a secure branching base part with a simple structure and small size by making combination use of a reinforcing material, hot melt adhesive and heat shrink tube. CONSTITUTION: A multi-core fiber tape-like optical fiber cord 122a is reinforced by using the reinforcing material, is integrated by using the hot melt adhesive and is integrated by thermal shrinkage using the heat shrinkable plastic tube at the time of branching the cord to single fiber cords 122b. namely, an MT connector 123 is mounted at one end of the four-fiber tape-like optical fiber 122a and the branching part 124 consists of the heat shrinkable plastic tube. A structure to branch the optical fiber to the single fiber optical fiber cords 122b is formed therein and reinforcing plates at are fixed at necessary points by making combination use of the hot melt adhesive. Each of the optical fiber cords branched to the single cores in such a manner is coated circumferentially with a tube, and single-fiber MT connectors 127 are fixed to every fiber at its end to obtain the branching part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a branch portion of a tape-shaped multi-fiber optical fiber, and particularly to a branch portion of a multi-fiber optical fiber having a compact and strong branch base with a simple structure. The present invention relates to a method and a branch structure.

[0002]

2. Description of the Related Art Conventionally, for forming a branch portion of a tape-shaped multi-core optical fiber, for example, as shown in FIG.
In the case of branching into 2b, the MT connector 23 is attached to one end of the four-core optical fiber cord 22a, the branching part is put in a case 24 similar to a connection box, and the internal void space is heated with polyester resin or epoxy resin. Optical fiber cords 2 each of which has a structure sealed with a curable resin 25 and is branched after branching
As shown in FIG. 5B, 2b is covered with, for example, a polyester thermoplastic elastomer (Toray DuPont Co., Ltd. product name: Hytrel) tube 26, and a single-core connector 27 is attached to the terminal portion, and as a whole, The configuration was similar to that of a multi-core branch cord with a 4-core connector at both ends.

[0003]

In the case of the conventional branching method as described above, since the metal branching case 24 is required, this portion is large in size and weight, and the branching case 24 is thermally cured. Since the resin 25 is filled and reinforced, the resin may squeeze out into the surroundings, and in order to prevent this, a sealing treatment is required, and the curing time of the thermosetting resin is long and often takes one day or night. However, it takes about 15 minutes even if a particularly fast-curing resin is selected, and it takes a long time to complete the branch portion, and in order to complete the branch portion, the number of parts is large, and most of the curable resins are Since it was a two-part type, it had to be cured in compliance with a specific compounding ratio, which was troublesome.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and uses a reinforcing material in branching a multi-core tape-shaped optical fiber cord into a single-core cord. Provided is a method and a branch for reinforcing, integrating using a hot melt adhesive, and integrating by heat shrinkage using a heat-shrinkable plastic tube to form a small and compact branch.

[0005]

In the case of the above-described optical fiber branching method and branching structure of the present invention, by using a reinforcing material, a hot-melt adhesive and a heat-shrinkable tube in combination, it is relatively simple, the external shape is small, and the weight is light. It is possible to obtain a branching method and a branching structure that require a short branching work time.

[0006]

1 is a simplified view of an optical fiber branching structure according to the present invention, FIG. 2 is a detailed view of an example of an optical fiber branching structure according to the present invention, and FIG. 3 is a heat-shrinkable tube, a hot melt adhesive and a reinforcing material. Is a perspective view showing an example of the relationship between the reinforcing material and the hot-melt adhesive, and FIG. 4 is a sectional view showing the relationship between the reinforcing material and the hot-melt adhesive. First, the present invention will be described with reference to FIG. 1. An MT connector 123 is attached to one end of a four-core tape-shaped optical fiber 122a, a branch portion 124 is made of a heat-shrinkable plastic tube, and details are shown inside. Although not provided, a structure for branching the optical fiber into a single-core optical fiber cord 122b is created, and a reinforcing plate is fixed to a necessary portion by using a hot melt adhesive together. In the case of a single-branched one, the periphery is covered with a hightrel tube, and one MT connector 127 is attached to each end at each end, so that a mechanically strong branched portion can be obtained very easily in a short time. be able to.

The reinforcing material (rigid metal, plastic, or rigid material such as glass) used for this may be plate-shaped, cylindrical or semi-cylindrical, and one side of a tape-shaped multi-fiber optical fiber. Alternatively, it may be attached on both sides. Also, hot melt adhesives are known ethylene
Appropriate materials such as a vinyl acetate copolymer system, an ethylene acrylic acid copolymer system, a polyamide system, a butyral system, and a polymethylmethacrylate system can be used. These hot melt adhesives have a low softening point and can be bonded at an operating temperature of 140 to 160 ° C. and an oven time of 4 to 6 seconds. As the heat-shrinkable tube, any one such as polyethylene type, polypropylene type, silicone rubber type can be used.

As shown in FIG. 3, a hot-melt adhesive 125 is applied to the inside of the heat-shrinkable plastic tube 126, and a branch portion of the tape-shaped multi-fiber optical fiber cord is arranged inside with a sheet-shaped reinforcing material 128. It can be seen that if the heat-shrinkable plastic tube 126 is heat-shrinked, the heat-shrinkable plastic tube 126 can be easily sealed to complete the branch portion. FIG. 4 shows a hot melt adhesive 1 between two sheets of reinforcing material 128.
Although the case where 25 is formed in a sheet shape and is interposed is shown, various structures other than this are conceivable, and the branch portion of the optical fiber cord may be integrally joined. FIG. 2 is a detailed view of a branched portion of an example of the present invention. The sheath at the end portion on the multi-core (four-core) optical fiber cord 222a side is stripped off to expose the multi-core optical fiber cord 122a. Reference numeral 121 is a Kevlar (aromatic polyamide fiber) used for reinforcement on the inner surface of the sheath. The tip of the four-core optical fiber cord 122a is branched to form a single-core optical fiber cord 122b (1), and a tip portion of the four-core optical fiber cord 122a is covered with a Hytrel tube to form the optical fiber cord 122b.
(2) Put on the Kevlar 121 and pull it out. At the branching portion of the four-core optical fiber cord 122a into four cores, for example, as shown in FIG. 3, a reinforcing material 128 is formed into a flat columnar shape and is covered with the reinforcing material 128. A heat-shrinkable tube 126 coated with an adhesive 125 is arranged so as to wrap the whole, and inside the branch part is easily adhered to the reinforcing plate 128 and the periphery by a hot-melt adhesive, and is integrated in an airtight manner by heat-shrinking. .

[0009]

As is apparent from the above description, the present invention, when branching a multi-core cord into a single-core cord, firmly holds the branch portion by the reinforcing plate, so that a disconnection accident at this portion occurs. Is hard to occur. Also, since hot melt adhesive is used at the same time, the bonding process can be done in an extremely short time, and the curing process at high temperature for a long time unlike ordinary adhesives is unnecessary. Even if a heat-shrinkable tube is used without using a box similar to a box, it branches with sufficient mechanical strength, and the cost of the heat-shrinkable tube itself is low, and it shrinks extremely due to shrinkage.
A lightweight and small bifurcation can be easily created in a short time.

[Brief description of drawings]

FIG. 1 is an explanatory view of an example of a branch structure of an optical fiber according to the present invention.

FIG. 2 is a detailed vertical sectional view of an example of an optical fiber branching structure according to the present invention.

FIG. 3 is a partial perspective view showing the relationship between the heat-shrinkable plastic tube, the hot-melt adhesive and the reinforcing plate used in the present invention.

FIG. 4 is a cross-sectional view showing a structure in which two reinforcing plates are joined with a hot melt adhesive.

5A is a simplified vertical sectional view of an example of a conventional optical fiber branching structure, and FIG. 5B is a sectional view showing an example of a branched fiber structure.

[Explanation of symbols]

22a 4 fiber optical fiber cord 22b Single fiber optical fiber cord 23 4 fiber MT connector 24 Branch case 25 Thermosetting resin 26 Polyester thermoplastic elastomer tube 27 Single fiber connector 121 Kevlar 122a 4 fiber optical fiber cord 122b (1) Single fiber Optical fiber cord 122b (2) Single-core optical fiber cord (Hytrel coating) 124 Branching portion 125 Hot melt adhesive 126 Heat shrinkable tube 128 Reinforcing plate

Claims (4)

[Claims] 1. When branching a multi-core tape-shaped optical fiber into a single-core optical fiber, a reinforcing material is applied to the base of the branching portion, and hot-melt adhesive is applied between the two or around them or between and both sides. A multi-core, characterized in that an agent is attached and inserted into a heat-shrinkable tube to cure the hot-melt adhesive and heat-shrink the heat-shrinkable tube to form an airtight and strong branch joint. A method for forming a branch portion of an optical fiber. 2. The method for forming a branched portion of a multi-fiber optical fiber according to claim 1, wherein the reinforcing material has a flat plate shape or a tube shape. 3. The method for forming a branched portion of a multi-fiber optical fiber according to claim 1, wherein the reinforcing material is selected from metal, plastic or glass. 4. A base for branching a multi-core tape-shaped optical fiber into a single-core optical fiber is provided inside a heat-shrinkable tube with a branch portion of the multi-core tape-shaped optical fiber and a reinforcing material between the two or A structure of a branching portion of a multi-core optical fiber, characterized in that it is joined by a hot melt adhesive in its peripheral portion and is hermetically integrated by heat shrinkage of the heat shrinkable tube.