JP2008151951A - Reinforcing structure of spliced portion of optical fiber, reinforcing method and reinforcing sleeve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing structure of a spliced portion of an optical fiber, in which a fused and spliced portion of an optical fiber is protected from tensile force and the diameter of a reinforcing portion reinforcing the spliced portion can be decreased, and to provide a reinforcing method and a reinforced sleeve. <P>SOLUTION: The present invention provides a reinforcing structure of a spliced portion of an optical fiber, a reinforcing method and a reinforcing sleeve, for reinforcing a spliced portion of an optical fiber where ends of optical fibers removed from coatings are butted, fused and spliced. The reinforcing structure of a spliced portion of an optical fiber is formed by disposing an inner tube 6 made of a hot-melt resin, a reinforcing member 7 molded by drawing a plurality of tension fibers 7b along the longitudinal direction into a tape shape with a hot-melt resin 7a, and a heat-shrinkable tube 8, in this order from the inside on the spliced portion Ps, melt-sticking the inner tube to the optical fiber by heating and shrinking the heat-shrinkable tube, and melt-sticking the inner tube and the hot-melt resin of the reinforcing member, so as to impart strength in the tensile direction to the spliced portion by the plurality of tension fibers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reinforcing structure, a reinforcing method, and a reinforcing sleeve for an optical fiber connecting portion.

  Conventionally, when the optical fiber is fused, the ends of the bare fibers exposed by removing the coating are brought into contact with each other and fused. For this reason, the mechanical strength of the portion of the bare fiber from which the coating has been removed decreases in the spliced optical fiber. Therefore, when the optical fiber is fusion spliced, for example, a tensile body made of a metal material such as a stainless steel rod or a non-metallic material such as glass or ceramic is placed along the connection portion and arranged on the outer periphery of the connection portion and the strength body. The portion of the bare fiber including the connection portion is encapsulated and reinforced by the heat shrinkable tube, thereby protecting the connection portion from the acting bending force and pulling force (for example, see Patent Document 1).

JP 2004-309841 A

  By the way, the optical fiber spliced and connected as described above may be incorporated in an optical component such as an optical connector in addition to a reinforced connection portion being housed in an optical communication device or the like. In such a case, it is more important for the connecting portion to protect against the tensile force than to protect against the bending. Moreover, the conventional reinforcing structure in which a tensile strength body such as a stainless steel bar is provided along the connecting portion has a problem that the diameter of the connecting portion becomes too large and the degree of freedom in use of the fusion-bonded optical fiber is restricted. there were.

  The present invention has been made in view of the above, and it is possible to reduce the diameter of the reinforcing portion that reinforces the connecting portion while protecting the spliced optical fiber connecting portion from the pulling force. An object is to provide a reinforcing structure, a reinforcing method, and a reinforcing sleeve for an optical fiber connecting portion.

  In order to solve the above-described problems and achieve the object, the reinforcing structure of the optical fiber connection portion according to claim 1 reinforces the connection portion that is fusion-bonded by abutting the ends of the optical fibers from which the coating has been removed. An optical fiber connecting portion reinforcing structure, wherein an inner tube made of hot melt resin and a plurality of tensile strength fibers aligned along the longitudinal direction are narrower than the outer peripheral length of the inner tube by the hot melt resin A reinforcing member formed in a shape and a heat shrinkable tube are arranged in the connecting portion in that order from the inside, and the inner tube is welded to the optical fiber along with the heat shrinkage of the heat shrinkable tube, and the inner tube A strength in a tensile direction is imparted to the connecting portion by the plurality of tensile strength fibers by welding the reinforcing member to the hot melt resin.

  Further, in order to solve the above-described problems and achieve the object, a method for reinforcing an optical fiber connection portion according to claim 3 is to provide a connection portion that is fusion-bonded by abutting the ends of optical fibers from which coating is removed. A method of reinforcing an optical fiber connecting portion to be reinforced, wherein an inner tube made of a hot-melt resin and a plurality of tensile strength fibers aligned along the longitudinal direction are narrower than an outer peripheral length of the inner tube by the hot-melt resin. A step of adhering a reinforcing member formed in a tape shape and a heat-shrinkable tube to one optical fiber fusion-bonded with a reinforcing sleeve arranged in that order from the inside; A step of moving the reinforcing sleeve to the fiber connecting portion to cover between the ends of the coating on both sides of the connecting portion; heating the reinforcing sleeve to contract the heat shrinkable tube; Characterized in that it comprises a step of imparting the strength of the pulling direction to the connecting portion by the optical fiber and the reinforcing hot-melt resin with the plurality of tensile strength fibers by welding the members to the inner tube, the.

  In order to solve the above-described problems and achieve the object, the reinforcing sleeve according to claim 5 is a reinforcing sleeve that reinforces the connection part that is fusion-bonded by abutting the ends of the optical fibers from which the coating has been removed. An inner tube made of a hot-melt resin, and a reinforcing member formed by forming the plurality of tensile fibers aligned along the longitudinal direction into a tape shape narrower than the outer peripheral length of the inner tube by the hot-melt resin, A heat-shrinkable tube is disposed in that order from the inside, and the inner tube is welded to the optical fiber in accordance with the heat shrinkage of the heat-shrinkable tube, and the inner tube and the reinforcing member are welded to the hot-melt resin. Further, the tensile strength is imparted to the connecting portion by the plurality of tensile strength fibers.

  Here, the heat shrinkable tube is transparent.

  The reinforcing structure, the reinforcing method, and the reinforcing sleeve of the optical fiber connection portion according to the present invention have a plurality of tensile strength fibers aligned along the longitudinal direction and are narrower than the outer peripheral length of the inner tube by a hot-melt resin made of the same material as the inner tube. The reinforcing member formed in a tape shape is used, and a tensile strength is imparted to the connection portion of the optical fiber by a plurality of strength fibers constituting the reinforcing member formed in the tape shape. For this reason, the reinforcing structure, the reinforcing method, and the reinforcing sleeve of the optical fiber connecting portion of the present invention reduce the diameter of the reinforcing portion that reinforces the connecting portion while protecting the connecting portion of the fusion-bonded optical fiber from a tensile force. There is an effect that the diameter can be increased.

  Hereinafter, embodiments of the reinforcing structure, the reinforcing method, and the reinforcing sleeve of the optical fiber connecting portion of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a reinforcing structure of an optical fiber connecting portion according to the present invention. FIG. 2 is a cross-sectional view taken along line C1-C1 in FIG.

  As shown in FIGS. 1 and 2, the reinforcing structure of the optical fiber connecting portion (hereinafter simply referred to as “reinforcing structure”) is formed by connecting the inner tube 6 and the reinforcing portion to the connecting portion Ps in which the two optical fibers 1 are fusion-connected. The member 7 and the heat-shrinkable tube 8 are arranged in this order from the inside, and the inner tube 6 is welded to the optical fiber 1 from which the coating has been removed, and the inner tube 6 and the hot-melt resin of the reinforcing member 7 are welded to reinforce the reinforcing member 7. The tensile strength is given to the connecting portion Ps by the plurality of tensile strength fibers 7b.

  At this time, as the inner tube 6, the reinforcing member 7, and the heat-shrinkable tube 8, as shown in FIGS. 3 and 4, those arranged in advance in this order from the inside are prepared as the reinforcing sleeve 5.

  The inner tube 6 is a tube formed from a hot melt resin, for example, a hot melt resin. As the hot melt resin, known resins such as ethylene vinyl acetate copolymer (EVA), polyolefin (PP), polyamide (PA), and synthetic rubber (SR) can be used. As shown in FIG. 1, the inner tube 6 is set to a length that covers a range from the spliced connection portion Ps of the optical fiber 1 to the end portions of the coating 1 a existing on both sides.

  As shown in FIG. 5, the reinforcing member 7 includes a plurality of tensile strength fibers 7 a aligned along the longitudinal direction, for example, aramid fibers, carbon fibers, glass fibers, and the like, using the same hot melt resin 7 b as the inner tube 6. 6 is formed in a tape shape that is narrower than the outer peripheral length of 6, and is arranged outside the inner tube 6 along the longitudinal direction. The reinforcing member 7 is set to have substantially the same length as the inner tube 6. Here, the reinforcing member 7 is formed to be narrower than the outer peripheral length of the inner tube 6 so that the connection portion Ps can be observed from the outside when the reinforcing sleeve 5 is attached to the optical fiber 1. ing. For this reason, the width of the reinforcing member 7 is determined from the viewpoints of observation from the outside of the connection portion Ps and imparting strength in the tensile direction to the connection portion Ps by the plurality of tensile strength fibers 7a.

  The heat-shrinkable tube 8 is a tube that is disposed outside and covers the inner tube 6 and the reinforcing member 7, and is molded using a known material such as polyvinyl chloride resin, fluorine resin, polystyrene resin, polyolefin resin, or the like. Is done. However, the heat shrinkable tube 8 is preferably transparent so that the connection portion Ps can be observed from the outside. In addition, when the heat shrinkable tube 8 is heated and shrunk, the inner tube 6 is welded to the optical fiber 1, and the inner tube 6 and the hot melt resin 7b of the reinforcing member 7 are welded, so that a plurality of tensile strength fibers 7a. Therefore, it is necessary to give the strength in the pulling direction to the connecting portion Ps. For this reason, it is preferable to use the heat shrinkable tube 8 whose shrinkage start temperature is the same as or higher than the melting temperature of the inner tube 6 or the hot melt resin 7b of the reinforcing member 7.

  The reinforcing structure configured as described above reinforces the connection portion Ps of the optical fiber 1 using the reinforcing sleeve 5 by the reinforcing method described below.

  First, prior to the fusion splicing of the two optical fibers 1, as shown in FIG. 6, the one optical fiber 1 with the coating 1a removed and the bare fiber 1b exposed is inserted through the inner tube 6, A reinforcing sleeve 5 is applied.

  Next, after the end portions of the bare fiber 1b are butted together and the two optical fibers 1 are fusion-spliced, the reinforcing sleeve 5 is moved to the connection portion Ps, and as shown in FIGS. 7 and 8, the optical fiber 1 The connecting portion 1a is covered with the reinforcing sleeve 5 so as to be disposed between the ends of the covering 1a on both sides of the connecting portion Ps. At this time, when the reinforcing sleeve 5 is formed so that the width of the reinforcing member 7 is narrower than the outer peripheral length of the inner tube 6 and the transparent heat-shrinkable tube 8 is used, the reinforcing operation is performed while observing the connection portion Ps from the outside. can do.

  Next, the reinforcing sleeve 5 covering the connecting portion Ps is heated. Thereby, as the heat shrinkable tube 8 contracts, the inner tube 6 is welded to the optical fiber 1, and the inner tube 6 and the hot melt resin 7b of the reinforcing member 7 are welded to the reinforcing sleeve 5. As shown in FIG. 1 and FIG. 2, the tensile strength is imparted to the connecting portion Ps by the plurality of tensile fibers 7a.

  At this time, the reinforcing sleeve 5 is heated so that the heating temperature at the center in the longitudinal direction is set to the maximum and the heating temperature decreases from the center toward both sides. When heated in this way, the inner tube 6 is welded to the optical fiber 1 from the center to both sides, and the inner tube 6 and the hot melt resin 7b of the reinforcing member 7 are welded from the center to both sides, The contraction tube 8 contracts from the center toward both sides. For this reason, the reinforcing sleeve 5 that covers the connecting portion Ps is less likely to have air bubbles inside, and even if the air bubbles enter the reinforcing sleeve 5 during heating, the air bubbles are outward as the heat shrinkable tube 8 contracts. It is preferable because it is extruded. Thus, by avoiding the mixing of bubbles into the connection portion Ps, the reinforcing structure of the present invention avoids repeated expansion and contraction of the bubbles due to the heat cycle, and is exposed by removing the connection portion Ps and the coating 1a. The portion of the bare fiber 1b can be protected from breakage due to microbending caused by expansion and contraction of bubbles.

  As described above, the reinforcing structure, the reinforcing method, and the reinforcing sleeve 5 according to the present invention have the outer peripheral length of the inner tube 6 by using the hot-melt resin 7b made of the same material as the inner tube 6 with the plurality of tensile fibers 7a aligned along the longitudinal direction. The reinforcing member 7 formed into a narrower tape shape is used, and the tensile strength is imparted to the connection portion Ps of the optical fiber 1 by a plurality of tensile fibers 7a. For this reason, the reinforcing structure, the reinforcing method, and the reinforcing sleeve 5 of the present invention include a reinforcing portion in which the connecting portion Ps is reinforced by the reinforcing sleeve 5 while protecting the connecting portion Ps of the fusion-bonded optical fiber 1 from a tensile force. The diameter can be reduced.

  Therefore, the connection part Ps of the optical fiber 1 including the reinforcing structure of the present invention can be housed in an optical communication device or the like, or incorporated into an optical component such as an optical connector. In addition, since the connection portion Ps of the optical fiber 1 is housed in an optical communication device or the like, or is incorporated in an optical component such as an optical connector, the housing of the optical component such as a housing of the communication device or the optical connector is used. Therefore, it is sufficient if the strength in the pulling direction is sufficient.

  The reinforcing member 7 used in the reinforcing structure and the reinforcing method of the present invention is formed by forming a plurality of tensile fibers 7a into a tape shape with a hot melt resin 7b, so that a conventionally used metal material such as a stainless steel rod is used. Unlike tensile strength bodies made of non-metallic materials such as glass, ceramic, etc., they can be cut easily. For this reason, the inner tube, the reinforcing member, and the heat shrinkable tube are preliminarily attached to the long inner shrinkable tube by attaching the long heat shrinkable tube along the long reinforcing tape serving as the reinforcing member to the long inner tube. It can be used by cutting into a desired length of the reinforcing sleeve every time the optical fiber is fusion spliced, so it is free to use compared to conventional reinforcing sleeves that use metallic materials as strength members. The degree has improved dramatically.

  Also, the thermoplastic resin other than the hot melt resin can be used as long as the hot melt resin is equal to or lower than the shrinkage start temperature of the heat shrinkable tube 8 and adheres to the optical fiber by melting and adheres to each other. May be used.

  Furthermore, although the above-mentioned embodiment demonstrated the reinforcement structure and reinforcement method of a single core optical fiber connection part, this invention is applicable also to reinforcement of a multi-core optical fiber connection part.

It is a longitudinal cross-sectional view which shows the reinforcement structure of the optical fiber connection part of this invention. It is sectional drawing along the C1-C1 line | wire of the reinforcement structure shown in FIG. It is a longitudinal cross-sectional view which shows the reinforcement sleeve of this invention. FIG. 4 is a cross-sectional view taken along line C2-C2 of the reinforcing sleeve shown in FIG. It is a perspective view of the reinforcement member used with the reinforcement sleeve of this invention. FIG. 4 is a cross-sectional view of a reinforcing sleeve shown in FIG. 3 attached to one optical fiber. FIG. 5 is a cross-sectional view of a connecting portion that is covered by a fusion sleeve by moving the reinforcing sleeve and bringing the ends of the optical fibers into contact with each other and fusion-bonding. FIG. 8 is a cross-sectional view taken along line C 3 -C 3 in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber 1a Coating | coated 1b Bare fiber 5 Reinforcement sleeve 6 Inner tube 7 Reinforcement member 7a Tensile fiber 7b Hot melt resin 8 Heat shrinkable tube Ps Connection part

Claims (6)

A reinforcing structure of an optical fiber connecting portion that reinforces a spliced and spliced connecting portion of optical fiber ends that have been removed,
An inner tube made of hot-melt resin;
A reinforcing member formed by tape forming a plurality of tensile fibers aligned along the longitudinal direction into a tape shape narrower than the outer peripheral length of the inner tube by the hot melt resin;
Heat shrink tubing,
Are arranged in the order from the inside to the connection part,
The inner tube is welded to the optical fiber along with the heat shrinkage of the heat-shrinkable tube, and the inner tube and the reinforcing member are welded to the hot melt resin. A reinforcing structure for an optical fiber connecting portion, characterized by providing the strength of:   The reinforcing structure for an optical fiber connection part according to claim 1, wherein the heat shrinkable tube is transparent. A method of reinforcing an optical fiber connecting portion that reinforces a spliced connection portion by butting the ends of optical fibers from which coating is removed,
An inner tube made of a heat-melting resin, a reinforcing member obtained by molding a plurality of tensile fibers aligned along the longitudinal direction into a tape shape narrower than the outer peripheral length of the inner tube by the heat-melting resin, and a heat-shrinkable tube And a step of adhering to one optical fiber fusion-bonded reinforcing sleeves arranged in that order from the inside,
A step of moving the reinforcing sleeve to the connection portion of the optical fiber that is fusion-connected by butting the ends, and covering between the ends of the coating on both sides of the connection portion;
The reinforcing sleeve is heated to shrink the heat-shrinkable tube, and the inner tube, the optical fiber, and the hot-melt resin of the reinforcing member are welded together, and the strength in the pulling direction is applied to the connection portion by the plurality of tensile strength fibers. A step of providing
A method for reinforcing an optical fiber connecting portion, comprising:   The method for reinforcing an optical fiber connection part according to claim 3, wherein the heat shrinkable tube is transparent. A reinforcing sleeve that reinforces a spliced connection by abutting the ends of an optical fiber from which the coating has been removed,
An inner tube made of hot-melt resin;
A reinforcing member formed by tape forming a plurality of tensile fibers aligned along the longitudinal direction into a tape shape narrower than the outer peripheral length of the inner tube by the hot melt resin;
Heat shrink tubing,
Are arranged in that order from the inside,
The inner tube is welded to the optical fiber along with the heat shrinkage of the heat-shrinkable tube, and the inner tube and the reinforcing member are welded to the hot melt resin. Reinforcing sleeve characterized by imparting strength of   The reinforcing sleeve according to claim 5, wherein the heat shrinkable tube is transparent.

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