JP2009271558A - Optical fiber bundling fixture and optical fiber bundle with bundling fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber bundle which is excellent in optical transmission performance and endurance, is rigidly adhered to a bundling fixture and is formed in a compact size, and to provide the bundling fixture suitably used for the optical fiber bundle. <P>SOLUTION: The optical fiber bundling fixture has a cylindrical hollow part and has a plurality of groove-shaped recesses which are extended in directions of circumference of the hollow part and are formed on the wall surface of the hollow part. Further, the optical fiber bundle is prepared by inserting and fixing an end of the optical fiber bundle composed of a plurality of optical fibers fused to one another at least in the end into the hollow part of the bundling fixture. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical fiber focusing tool and an optical fiber bundle with a focusing tool.

  Conventionally, an optical fiber bundle formed by converging a plurality of optical fibers is inserted into a base used as a focusing tool, and the base between the optical fibers and the optical fiber bundle and the base are fixed with an adhesive. A bundle of attached optical fibers is known. However, such an optical fiber bundle has a low optical transmission performance because the adhesive is interposed in the gap between the optical fibers or between the optical fiber bundle and the base, and is used by connecting the optical fiber bundle to a light source. It was.

On the other hand, by inserting the optical fiber bundle into the metal base and heating them, the optical fiber is enlarged and the optical fiber is softened to fuse the optical fiber and between the optical fiber bundle and the base. There has been proposed a method for fixing an optical fiber bundle. For example, in Patent Document 1, a base whose inner diameter is partly larger than the diameters at both ends of the base is used as the base, an optical fiber is inserted into the base, and the optical fiber is enlarged by heating. A method of filling an optical fiber enlarging in a portion having an increased inner diameter and fixing the optical fiber and the base is disclosed in Patent Document 2 in the base whose diameter increases toward the tip. A method is disclosed in which an optical fiber bundle is inserted so that the end face of the optical fiber is positioned on the side, and the optical fiber is enlarged and fixed by heating. However, these methods have a drawback in that the optical transmission performance is deteriorated because the cross-sectional shape of the optical fiber disposed in the vicinity of the inner wall of the die is distorted by heating during fusion.
As a means for solving these problems, Patent Document 3 discloses a method of fusing and fixing an optical fiber in a focusing tool made of a thermoplastic resin.

However, since this method uses a thermoplastic resin as a bundling tool, its strength is inferior to that of a metal base, and if a metal base is placed on the outer periphery of a thermoplastic bundling tool to obtain strength, an optical fiber is used. The area of the part that does not contribute to the light transmission on the bundle end face is increased, the ratio of the area of the base end face where the light is incident is reduced, and the base is increased if an attempt is made to sufficiently secure the area of the light incident part. There was a problem.

JP 51-144632 A JP 50-153943 A JP-A-11-101916

  An object of the present invention is to provide a compact optical fiber bundle with a focusing tool and a focusing tool suitably used for the optical fiber bundle, which are excellent in optical transmission performance and durability, and in which an optical fiber bundle and a focusing tool are firmly fixed. It is in.

  The gist of the present invention is an optical fiber focusing tool that has a cylindrical hollow portion, and a plurality of groove-shaped concave portions extending in the circumferential direction of the hollow portion are formed on the wall surface of the hollow portion. Further, the optical fiber bundle is formed by inserting and fixing an end portion of an optical fiber bundle composed of a plurality of optical fibers fused to each other at least at the end portion in the hollow portion of the focusing tool.

  An optical fiber bundle with a focusing tool using the focusing tool of the present invention is excellent in light transmission performance and durability, and the optical fiber bundle and the focusing tool are firmly fixed, and is compact.

It is sectional drawing of the optical fiber bundle with a focusing tool by one Embodiment of this invention.

  The present invention will be described in detail below.

  FIG. 1 is a cross-sectional view in the longitudinal direction of an optical fiber of an embodiment of an optical fiber bundle with a focusing tool of the present invention. The focusing tool 2 has a cylindrical hollow portion into which an end portion of an optical fiber bundle 1 composed of a plurality of optical fibers fused to each other at least at the end portion is inserted. A concave portion 3 is formed on the wall surface of the hollow portion, and the focusing tool 2 and the optical fiber bundle 1 are bonded and fixed by an adhesive. By tightly filling the concave portion 3 with the adhesive, the focusing tool and the optical fiber bundle can be firmly fixed even with a small amount of adhesive. In addition, even when separation occurs between the optical fiber bundle and the focusing tool, the optical fiber bundle is pulled from the focusing tool because the optical fiber bundle is locked to the concave part via an adhesive filled in the concave part. It is hard to come off. Further, in this optical fiber with a focusing tool, the focusing tool and the optical fiber bundle are bonded and fixed mainly by an adhesive filled in the recess, and the outer periphery of the optical fiber bundle and the focusing tool are arranged near the end face of the optical fiber bundle. Since the wall surface of the hollow part is almost in contact, the adhesive is hardly exposed between the optical fiber bundle and the focusing tool at the end face of the optical fiber bundle. Therefore, this optical fiber bundle with a focusing tool is excellent in optical transmission performance because the adhesive has a small effect on the optical transmission performance of the optical fiber bundle, and the area of the light incident portion that is applied to the end face of the optical fiber bundle with the focusing tool is reduced. Since it can be enlarged, a focusing tool can be formed compactly. Further, since the adhesive is hardly deteriorated by heat from the light source when the end face of the optical fiber bundle with a focusing tool is connected to the light source device, it is excellent in durability.

In the present embodiment, the optical fiber bundle and the focusing tool are bonded and fixed with an adhesive, but the optical fiber bundle and the focusing tool can be fused and fixed. In this case, since the material of the optical fiber bundle is closely packed in the recess, the focusing tool and the optical fiber bundle can be firmly fixed.
In the present embodiment, the concave portion is formed on the wall surface of the hollow portion, but it is also possible to form a convex portion instead of the concave portion, or to form the concave portion and the convex portion.

  The shape of the concave portion or the convex portion is not particularly limited, and for example, a groove shape or a bowl shape, a spiral shape, a concave shape or a convex portion that extends continuously, intermittently, or partially in the circumferential direction of the hollow portion. It can be scattered or pear-like. Among these, it is preferable that a plurality of groove-like recesses extending in the circumferential direction of the hollow portion can be desired. In order to fully fill the space formed between the converging tool and the optical fiber bundle by the concave part or the convex part and firmly fix the optical fiber bundle and the converging tool, the depth of the concave part or the convex part The height is preferably 0.2 mm or more, and the shortest width among the widths in the wall surface direction of the hollow portions of the recesses and projections is preferably 0.5 mm or more. The upper limit of the depth of the concave portion, the height of the convex portion, and the width of the concave portion and the convex portion is not particularly limited, but is usually 3 mm or less in order to easily manufacture the focusing tool.

  The cross-sectional shape of the hollow part of the focusing tool of the present invention is not particularly limited, and may be a circular shape or a polygonal shape such as a quadrangle. As the optical fiber, an optical fiber made of plastic or glass and capable of being fused with each other is used. Moreover, a well-known thing is used as a material of a focusing tool, For example, what consists of metal, a plastics, etc. is used.

  Also, a known method is used as a method for fusing together a plurality of optical fibers at the end of the optical fiber bundle. For example, the ends of the plurality of optical fibers are inserted into the hollow portion of a known focusing jig. And a method of heat-treating the focusing jig and the optical fiber inserted into the hollow portion. In this case, for example, when a plastic fiber is used as the optical fiber, it is preferable that the heating temperature be equal to or higher than the heat deformation temperature of the plastic constituting the optical fiber and equal to or lower than the melting temperature.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1

One end of an optical fiber 5 composed of 430 optical fibers having a diameter of 0.5 mm is converged into a substantially circular shape having a diameter of 12 mm, inserted into a hollow portion of a focusing jig having a cylindrical hollow portion, and heat-treated. An optical fiber bundle obtained by fusing the optical fibers at the end was obtained. This optical fiber bundle was inserted into a cylindrical hollow portion of an aluminum cylindrical focusing tool, and an adhesive was filled between the optical fiber bundle and the focusing tool to bond and fix the optical fiber bundle and the focusing tool. The outer diameter of the focusing tool at the portion where the end of the optical fiber bundle is inserted was 15 mm, the inner diameter of the hollow part was 12 mm, and the length of the focusing tool in the central axis direction of the hollow part was 50 mm. On the inner wall of the hollow portion of the focusing tool, five groove-shaped concave portions extending in the circumferential direction of the hollow portion having a width of 1 mm and a depth of 0.3 mm were formed at a pitch of 1 mm.
Next, the end face of the optical fiber bundle was polished to obtain an optical fiber bundle with a focusing tool.

  When light was incident on the obtained optical fiber bundle with a focusing tool, the transmission performance of the optical fiber bundle was good. Further, when the pulling strength of the optical fiber bundle and the focusing tool was measured, it was pulled out about 3 times as compared with the optical fiber bundle with the focusing tool manufactured in the same manner as described above except that the focusing tool having no recess was used. Strength improved. The drawing strength was measured by setting the total length of the optical fiber bundle with a focusing tool to 300 mm, using a large tensilon, and setting the drawing speed to 5 m / min.

1 Optical fiber bundle 2 Focusing tool 3 Recess

Claims (2)

  An optical fiber focusing tool having a cylindrical hollow portion, wherein a plurality of groove-shaped concave portions extending in the circumferential direction of the hollow portion are formed on a wall surface of the hollow portion.   An optical fiber bundle in which an end portion of an optical fiber bundle composed of a plurality of optical fibers fused at least at an end portion is inserted and fixed in the hollow portion of the focusing tool according to claim 1.

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