JPH1123880A - Reinforcing structure of optical fiber fusion splicing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect an optical fiber and to make the fusion splicing part applicable to the connection of the optical fiber by covering the fusion splicing part with a rigid outer shell, filling adhesive inside and forming an elastic tubular protection layer on the surface of a part of the optical fiber. SOLUTION: A fusion splicing part 2 is covered with an outer shell 9 and adhesive is filled inside the part covered with the outer shell. Preferable adhesive 10 has high viscosity and a high curing speed, the ultraviolet curing adhesive is used for the adhesive 10 and the outer shell 9 is composed of ultraviolet curing glass correspondingly. The outer shell 9 is divided into semi-cylindrical parts 9a, 9b and the cylinder is formed by joining the respective parts 9a, 9b. An elastic tubular protection layer covers the surface of a part out of the end part of the outer shell 9 of the optical fiber 1. Consequently, by exerting the bending stress on the outer shell 9, the bending stress exerted on the fusion splicing part 2 is prevented and the bending radius of the part out of the end part of the outer shell 9 of the optical fiber 1 is restricted by the protection layer 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reinforcing an optical fiber fusion splicing portion for reinforcing a fusion splicing portion between optical fibers.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing a conventional example of a reinforcing structure for an optical fiber fusion splicing portion of this kind. In the figure, 1
Denotes an optical fiber, and 2 denotes a fusion spliced portion between the optical fibers. The fusion splicing portion 2 is covered with an inner tube 6 and is covered with an outer tube 8 together with a strength member 7 arranged outside the inner tube 6.

Conventionally, the internal tube 6 and the external tube 8 are simultaneously thermally contracted and hardened to reinforce the fusion spliced portion 2 with the above configuration.

[0004]

However, according to the prior art having the above-mentioned structure, since the end of the reinforcing structure is hard, there is no problem in connecting the core of the optical fiber. There is a problem that the fiber may be broken. In view of the above problems, the present invention provides a configuration that resists bending stress at the central portion of the fusion spliced portion and appropriately absorbs bending stress at the end portion, and converts the optical fiber from bending stress such that disconnection occurs. An object of the present invention is to provide a reinforcing structure of an optical fiber fusion splicing portion which can be protected and applicable to connection of a strand.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention completely blocks transmission of bending stress to a fusion splicing portion, and receives light while receiving bending stress at an end of a reinforcing structure. The bending radius of the fiber is regulated within an appropriate amount. That is, the present invention provides a reinforcing structure of an optical fiber fusion splicing portion for reinforcing a fusion splicing portion between optical fibers, wherein the fusion splicing portion is covered with a rigid outer shell,
The inside covered with the outer shell is filled with an adhesive, and the surface of the optical fiber at the part protruding from the end of the outer shell is coated with an elastic tube-shaped protective layer.

Here, the protective layer has a thickness of 0.3 mm or more.
It is preferable to use a 1.0 mm synthetic rubber or plastic. Further, it is preferable that the outer shell is made of an ultraviolet transmitting glass and the adhesive is an ultraviolet curing adhesive.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view showing one embodiment of the present invention, FIG. 2 is a side sectional view of the same, and FIG. 3 is a sectional view taken along line AA of FIG. In the drawing, 1 is an optical fiber, and 2 is a fusion spliced portion between optical fibers.

Reference numeral 9 denotes a rigid outer shell that covers the fusion splicing portion 2, and reference numeral 10 denotes an adhesive that is filled in the inside covered by the outer shell. It is desirable that the adhesive 10 has a high viscosity and a high curing speed. In the present embodiment, an ultraviolet-curable adhesive is used as the adhesive 10 and the outer shell 9 is correspondingly used.
Is made of ultraviolet transmitting glass. The outer shell 9 is divided into semi-cylindrical parts 9a and 9b, and these parts 9a and 9b are combined to form a cylindrical shape.

Reference numeral 11 denotes a protective layer in the form of an elastic tube, which covers the surface of the optical fiber 1 from the end of the outer shell 9. In the present embodiment, the coating of the protective layer 11 is continued not only at the part protruding from the end of the outer shell 9 but also at a part slightly entering the end of the outer shell 9 from the viewpoint of ease of manufacture and durability against stress. The material of the protective layer 11 is a heat-shrinkable material such as synthetic rubber or plastic. The thickness of the protective layer is set according to the limit of the bending radius of the optical fiber 1 and the material of the protective layer.
By setting the length in the range from mm to 1.0 mm, it is possible to restrict the bending radius of the optical fiber 1 from becoming small until it breaks.

The manufacturing procedure of the present embodiment having the above configuration is as follows. First, a protective layer 11 is coated on a designated position of the optical fiber 1 to be fused. Subsequently, the coating of the optical fiber 1 is removed and fusion spliced. One part 9a of the outer shell 9
Is placed so that the fusion splicing part 2 is located at the center of, and the adhesive 4 is applied so that air bubbles do not appear, and the other part 9b is covered.

Finally, the adhesive 4 is cured by applying ultraviolet rays. At this time, since the outer shell 9 is transparent to ultraviolet rays, the ultraviolet rays pass through the outer shell 9 to reach the adhesive 10 and act. With the above configuration, the present embodiment operates as follows. First, by fixing the fusion splicing portion 2 with the adhesive 10 and the outer shell 9 so as not to move, the bending stress is received by the outer shell 9 and the bending stress is not applied to the fusion splicing portion 2 completely. .

Although the optical fiber 1 at the portion protruding from the end of the outer shell 9 is subjected to bending stress, its bending radius is regulated by the protective layer 10 and does not become small until disconnection.

[0013]

As described above in detail, according to the present invention, in a reinforcing structure of an optical fiber fusion splicing part for reinforcing a fusion splicing part between optical fibers, the fusion splicing part is formed of a rigid outer joint. The inside covered with the shell was filled with an adhesive, and the surface of the partial optical fiber emerging from the end of the shell was coated with an elastic tube-shaped protective layer. The transmission of the bending stress of the optical fiber can be completely blocked, and the bending radius of the optical fiber can be restricted within an appropriate amount while receiving the bending stress at the end of the reinforcing structure.

This makes it possible to withstand the bending stress at the center of the fusion spliced portion and to absorb the bending stress at the end appropriately, thereby protecting the optical fiber from the bending stress that would cause the disconnection. There is an effect of providing a reinforcing structure of the optical fiber fusion splicing portion applicable to the connection of the optical fiber.
At this time, the protective layer has a thickness of 0.3 mm to 1.0 mm.
By being composed of synthetic rubber or plastic,
There is an effect that appropriate elasticity and reinforcing force can be obtained at low cost.

[0015] Further, the outer shell is made of an ultraviolet-transmitting glass, and the adhesive is made of an ultraviolet-curable adhesive.
It is possible to obtain a high viscosity and a high curing rate in the adhesive layer, and there is an effect that an easy-to-manufacture and durable reinforcing structure of the optical fiber fusion splicing part is realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing one embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a perspective view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Fusion-spliced part 9 Outer shell 10 Adhesive 11 Protective layer

Claims (3)

[Claims] 1. A reinforcing structure for an optical fiber fusion splicing portion for reinforcing a fusion splicing portion between optical fibers, wherein the fusion splicing portion is covered with a rigid outer shell, and the interior covered with the outer shell is bonded. A reinforcing structure for an optical fiber fusion spliced part, wherein an agent is filled, and a surface of the optical fiber at a part protruding from an end of the outer shell is coated with an elastic tube-shaped protective layer. 2. An optical fiber according to claim 1, wherein said protective layer is made of synthetic rubber or plastic having a thickness of 0.3 mm to 1.0 mm. Reinforcing structure of fusion spliced part. 3. The optical fiber according to claim 1, wherein the outer shell is made of an ultraviolet-transmissive glass, and the adhesive is an ultraviolet-curable adhesive. Reinforcing structure of fusion spliced part.