JP2003121692A - Method of fixing optical fiber to reinforcing tube and mounting method of optical ferrule - Google Patents

Abstract

(57) [Problem] To prevent bending of an optical fiber when inserting and fixing an optical fiber housed in a reinforcing tube into an optical ferrule. SOLUTION: An optical fiber cord 3 is constituted by housing an optical fiber 1 in a reinforcing tube 2. The portion of the optical fiber 1 and the reinforcing tube 2 of the optical fiber cord 3 are held by a pair of holders 11 and 12 with V-grooves.
The optical fiber 1 and the reinforcing tube 2 are positioned, and then, in a state where the two are separated from each other in the longitudinal direction of the optical fiber and the optical fiber 1 is pulled, an adhesive is filled in the vicinity of the distal end of the reinforcing tube 2 to form the optical fiber 1. To the reinforcing tube 2. Center position of optical fiber 1 and reinforcing tube 2
When the optical fiber is inserted into the optical ferrule, the optical fiber can be smoothly inserted into the optical fiber insertion hole of the optical ferrule, which prevents the optical fiber from being bent or broken. Can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cord having an optical fiber housed in a reinforcing tube,
The present invention relates to a method for fixing a portion near the tip of a tube of an optical fiber protruding from a reinforcing tube to the reinforcing tube with an adhesive, and an optical ferrule attaching method for attaching an optical ferrule to this optical fiber cord.

[0002]

2. Description of the Related Art When attaching an optical ferrule to an optical fiber cord formed by storing an optical fiber in a reinforcing tube,
Normally, the area near the tube tip of the optical fiber that is exposed from the optical fiber cord is fixed to the reinforcing tube with an adhesive, but the work of adhering and fixing this optical fiber to the reinforcing tube is a manual work, and in the past, it was simply done inside the reinforcing tube. The vicinity of the tip of the optical fiber was filled with an adhesive to fix the portion of the optical fiber near the tube tip to the reinforcing tube.

FIG. 7 shows an optical fiber cord manufactured by a conventional method. Reference numeral 1 is an optical fiber, 2 is a reinforcing tube, and the optical fiber 1 is housed in a reinforcing tube 2 to form an optical fiber cord 3. ing. The optical fiber 1 is projected from the reinforcing tube 2, and a portion of the optical fiber 1 near the tube tip is fixed to the reinforcing tube 2 with an adhesive 4. The optical fiber cord 3 in the illustrated example is, for example, a 0.25 mm diameter UV core wire for the optical fiber 1, and a 0.9 mm outer diameter, 0.5 mm inner diameter plastic tube made of nylon or the like for the reinforcing tube 2.

[0004]

SUMMARY OF THE INVENTION As described above, conventionally,
The adhesive 4 is bluntly filled in the vicinity of the tip of the reinforcing tube 2 so that the optical fiber 1 can be used without considering the distance between the reinforcing tube 2 and the optical fiber 1 and thus without using a jig or the like for setting the distance. The portion near the tip of the tube was fixed to the reinforcing tube 2. However, in this method, as shown in FIG. 7, the optical fiber (core wire) 1 is likely to come into contact with or come close to the inner surface of the reinforcing tube 2. The center of 1 and the center of the reinforcing tube 2 do not coincide. That is, the optical fiber 1 is fixed to the reinforcing tube 2 while being eccentric to the reinforcing tube 2.

When the above optical fiber cord 3 is attached to a single-core optical ferrule (such as a SC optical connector ferrule of JISC 5973), the optical fiber cord 3 is attached as shown in FIG. 6, for example. That is, the bare fiber 1a is obtained by removing the UV coating on the portion of the optical fiber 1 which is exposed from the reinforcing tube 2, and the bare fiber 1a portion is used as the optical fiber insertion hole 6 of the ferrule body 6 of the optical ferrule 5.
a and insert the vicinity of the tip of the reinforcing tube 2 into the cylindrical hole 7a in the metal flange portion 7 of the optical ferrule 5,
Adhesive fixing is performed by the adhesive 8 filled in advance.

As described above, the bare fiber 1 of the optical fiber 1
When a is inserted into the optical fiber insertion hole 6a of the optical ferrule 5, if the center of the optical fiber 1 and the center of the reinforcing tube 2 do not coincide with each other, the tapered guide surface 6b is formed on the ferrule body 6 as shown in FIG. Even if formed, it is difficult for the bare fiber 1a to enter the optical fiber insertion hole 6a of the ferrule body 6 because the tip of the bare fiber 1a hits a portion other than the tapered guide surface 6b,
The optical fiber 1 (bare fiber 1a) is likely to be bent or broken. However, the inner diameter of the reinforcing tube 2 is 0.
Since it is as thin as 5 mm, conventionally, it was not considered whether or not the optical fiber 1 is at the center of the thin tube.

The present invention has been made in view of the above circumstances, and is a work of attaching an optical ferrule to an optical fiber cord having an optical fiber housed in a reinforcing tube, and bending the optical fiber when inserting the optical fiber into the optical ferrule. Another object of the present invention is to provide a method for fixing an optical fiber to a reinforcing tube and a method for attaching an optical ferrule, which does not cause the problem of breakage.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention of claim 1 is to bond an optical fiber cord formed by housing an optical fiber in a reinforcing tube to a portion near the tip of the tube of the optical fiber protruding from the reinforcing tube. A method of fixing an optical fiber to a reinforcing tube in which the adhesive is filled in the vicinity of the tip inside the reinforcing tube with the portion near the tip of the optical fiber positioned at the center of the reinforcing tube. Then, a portion of the optical fiber near the tube tip is adhesively fixed to the center position of the reinforcing tube.

A second aspect of the present invention is an optical ferrule attachment method characterized in that an optical ferrule is attached to the optical fiber cord manufactured by the method of the first aspect.

The invention of claim 3 is an optical ferrule attachment method for attaching an optical ferrule to the optical fiber cord produced by the method of claim 1, wherein the adhesive is used to fix the optical fiber to the reinforcing tube. Is characterized in that different adhesives are filled in the optical ferrule, and the optical fiber and the reinforcing tube exposed from the optical fiber cord are inserted into the optical ferrule to fix the optical fiber and the reinforcing tube to the optical ferrule.

A fourth aspect of the present invention is the optical ferrule attachment method according to the third aspect, wherein the optical ferrule is a single-core optical ferrule with a collar.

According to a fifth aspect of the present invention, in the method of fixing an optical fiber to a reinforcing tube according to the first aspect, the optical fiber and the reinforcing tube of the optical fiber cord are held by a pair of holders with V-grooves that can approach and separate from each other. Then, in a state where the end faces of the pair of V-grooved holders are set apart from each other in the longitudinal direction of the optical fiber, a portion of the optical fiber near the tube tip is bonded to the reinforcing tube.

[0013]

1 is a schematic view for explaining a method of fixing an optical fiber to a reinforcing tube according to an embodiment of the present invention, in which an optical fiber 1 and a reinforcing tube 2 of an optical fiber cord 3 are positioned. FIG. 2 is a plan view of a state (however, the pressing plate is omitted) set in a pair of holders 11 and 12 with V-grooves that form the device 10, and FIG. 2 is a sectional view taken along the line AA of FIG. 3 is a BB sectional view of FIG. 2, and FIG. 4 is a CC sectional view of FIG.

As shown in the figure, as described in the conventional example, the optical fiber 1 is housed in the reinforcing tube 2 to form the optical fiber cord 3, and the optical ferrule is attached to the optical fiber cord 3. For the optical fiber 1
From the reinforcing tube 2. One of the V-grooved holders 11 has a V-groove 11a on which the optical fiber 1 is placed,
The other V-grooved holder 12 is a V on which the reinforcing tube 2 is placed.
The groove 12a is provided. These V-grooves are aligned in the longitudinal direction of the optical fiber. Each V groove is provided with a pressing plate 13 and 14, respectively. In addition, the holding plates 13, 1
Reference numeral 4 denotes a structure that is coupled to the V-grooved holders 11 and 12, respectively. Specifically, a metal plate-shaped lid is hinge-coupled to a side portion of each holder and is a publicly known structure that is openably and closably attached by a magnet or the like. Can be adopted. Detailed illustration is omitted. The two V-grooved holders 11, 12 are shown in FIG.
Can relatively slide in the horizontal direction of the arrow (a) and in the vertical direction of the arrow (b) in FIG. 2, that is, the relative position can be adjusted. Usually, the relative position of the holder is temporarily fixed, and the temporary position is released and the relative position is finely adjusted only when the tube type is different. As a mechanism for adjusting the relative position of the target product, for example, one V-grooved holder 11 can be moved vertically and horizontally, and the other V-grooved holder 12 is fixed. The mechanism for making this movable may be an ordinary mechanism, and is not shown. Further, the left and right holders are directly or indirectly connected to each other by a slide shaft or the like so that they can approach and separate from each other. In this embodiment, for example, one V-grooved holder 11 is slidable also in the optical fiber longitudinal direction indicated by an arrow (c) in FIGS. 1 and 2.

The operation of fixing the optical fiber 1 to the reinforcing tube 2 using the positioning device 10 will be described. First, the tip portion of the reinforcing tube 2 of the optical fiber cord 3 is removed, and the optical fiber 1 is attached to the reinforcing tube 2 as shown in the figure.
Utter from Then, the lead-out portion of the optical fiber 1 and the reinforcing tube 2 are connected to the V-grooves 1 of the V-grooved holders 11 and 12.
It is put on 1a and 12a, respectively, and is held down by the holding plates 13 and 14. Here, the left and right holder side surfaces facing each other are flush with each other, and are in the closest positional relationship. Next, the V-grooved holder 11 on the optical fiber 1 side is lightly moved in the longitudinal direction of the optical fiber indicated by the arrow (c) to be separated from the optical fiber 1.
Is pulled lightly to eliminate the slack of the optical fiber 1.

Since the V-grooved holder 11 on the side of the optical fiber 1 has already been moved and adjusted vertically and horizontally, the axis of the reinforcing tube 2 and the optical fiber 1 are aligned, but the optical fiber 1 By pulling the fiber, the concentricity of the optical fiber 1 particularly near the tube tip and the central position of the reinforcing tube 2 is improved. Further, in this state, since a gap is formed between the left and right holder side surfaces facing each other, at this portion, for example, a thermosetting epoxy resin adhesive 4 is applied inside the reinforcing tube 2 as shown in FIG. When the adhesive 4 is hardened, the portion near the tube tip of the optical fiber 1 is bonded and fixed to the center position of the reinforcing tube 2 when the adhesive 4 is cured. In addition, after the adhesive 4 is filled in the vicinity of the tip of the reinforcing tube 2 in advance, before the adhesive 4 is completely cured,
It is also possible to adjust the positioning of the optical fiber 1 with respect to the reinforcing tube 2.

The operation of attaching the optical ferrule to the optical fiber cord 3 in which the optical fiber 1 is fixed to the center position of the reinforcing tube 2 as described above will be described with reference to FIG. This optical ferrule 5 is for a single core, and has a stainless steel flange portion 7 at the rear end of a cylindrical ferrule body 6 made of zirconia having an optical fiber insertion hole 6a at the center and a tapered guide surface 6b at the rear end surface. Is fixed. So-called S
C type optical connector (JISC 5973 etc.), or
This is an optical connector ferrule with a similar shape. An adhesive 8 different from the adhesive 4 used for fixing the optical fiber 1 to the reinforcing tube 2 in the cylindrical hole 7a of the flange portion 7 of the optical ferrule 5 in advance, for example, a room temperature curing type epoxy resin adhesive. Is filled. The bare fiber 1a is obtained by removing the UV coating from the portion of the reinforcing tube 2 of the optical fiber 1 which is inserted into the optical fiber insertion hole 6a of the ferrule body 6 of the optical ferrule 5 and the reinforcing tube 2 When the vicinity of the tip is inserted into the cylindrical hole 7a in the flange portion 7 of the optical ferrule 5, the optical fiber 1 (bare fiber 1a) and the reinforcing tube 2 are fixed to the optical ferrule 5 with the adhesive 8. The outer peripheral surface of the reinforcing tube 2 is also adhered and fixed to the flange portion 7 with the adhesive 8 that has penetrated into the gap between the inner surface of the cylindrical hole 7a of the flange portion 7.

The bare fiber 1 of the optical fiber 1 as described above
When a is inserted into the optical fiber insertion hole 6a of the optical ferrule 5, the center of the optical fiber 1 and the center of the reinforcing tube 2 are aligned with each other, so that the tip of the bare fiber 1a is larger than the position of the optical fiber insertion hole 6a. It does not warp. Therefore, even if the tip of the bare fiber 1a hits the tapered guide surface 6b, it is smoothly guided by the tapered guide surface 6b and easily enters the optical fiber insertion hole 6a. Therefore, there is no possibility that the optical fiber 1 (bare fiber 1a) will be bent. Since the inner diameter of the reinforcing tube 2 is 0.5 mm, which is extremely small, even if the optical fiber 1 is eccentric in the reinforcing tube 2, the amount of eccentricity is slight, but attention is paid to the slight amount of eccentricity. By eliminating the eccentricity,
The bare fiber 1a can be smoothly inserted into the optical fiber insertion hole 6a.

In the embodiment, the optical fiber cord 3 in which only the optical fiber 1 is housed in the reinforcing tube 2 is provided.
However, if a large-diameter tube is used, it can also be applied to an optical fiber cord in which a Kevlar (aramid fiber) layer is interposed between the optical fiber 1 and the inner surface of the reinforcing tube 2. In this case, the adhesive agent for fixing the optical fiber 1 to the reinforcing tube 2 permeates the Kevlar layer.

In the embodiment, the case of the single-core optical fiber has been described, but the present invention can also be adopted in the case of positioning and fixing the multi-core optical fiber tape in the reinforcing tube, for example. Furthermore, different kinds of adhesives are, for example, the same type of epoxy-based adhesives and there is a difference in curing time, or in the case of heat-curing type and not, in the case of a difference in composition, other, There are various forms such as the adoption of resins other than epoxy. In either case, boundaries can be found between the dissimilar adhesives within the flange.

[0021]

According to the present invention, the central position of the optical fiber and the central position of the reinforcing tube are aligned with each other by adhering and fixing the portion of the optical fiber near the tube tip to the central position of the reinforcing tube. When inserting the fiber into the optical ferrule, the optical fiber can be smoothly inserted into the optical fiber insertion hole of the optical ferrule, and the bending of the optical fiber can be prevented.

According to a fifth aspect of the present invention, the optical fiber and the reinforcing tube are respectively held by a pair of holders with V-grooves that can be moved toward and away from each other, and the end faces of the pair of holders with V-grooves are arranged in the longitudinal direction of the optical fiber. In the state of being separated to some extent,
By bonding the portion of the optical fiber near the tube tip and the reinforcing tube, the concentricity between the portion of the optical fiber near the tube tip and the center of the reinforcing tube 2 is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a method of fixing an optical fiber to a reinforcing tube according to an embodiment of the present invention, in which the optical fiber and the reinforcing tube are set in a pair of V-grooved holders that form a positioning device. It is a top view (however, a presser plate is abbreviate | omitted).

FIG. 2 is a vertical cross-sectional view of FIG. 1 (however, a pressing plate is shown).

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line CC of FIG.

5 is a diagram showing a state in which an adhesive is filled in the reinforcing tube in the state of FIG. 2 and the optical fiber is fixed to the reinforcing tube.

FIG. 6 is a view common to the present invention and a conventional example, and is a partial cross-sectional view showing a state in which an optical ferrule is attached to an optical fiber cord in which an optical fiber is housed in a reinforcing tube.

FIG. 7 is a diagram showing an optical fiber cord in which an optical fiber is fixed to a reinforcing tube by a conventional method.

[Explanation of symbols]

1 optical fiber 1a bare fiber 2 Reinforcement tube 3 Optical fiber cord 4 adhesive 5 optical ferrule 6 Ferrule body 6a Optical fiber insertion hole 6b Tapered guide surface 7 Flange 7a Cylindrical hole 8 adhesive 10 Positioning device 11 V-groove holder (on the optical fiber side) 12 Holder with V-groove (for reinforcing tube) 11a, 12a V groove 13, 14 Presser plate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yukio Hayashi             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Sa Co., Ltd.             Inside the warehouse (72) Inventor Yasuhiro Tamaki             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Sa Co., Ltd.             Inside the warehouse F-term (reference) 2H036 PA02 QA23

Claims (5)

[Claims] 1. A method for fixing an optical fiber to a reinforcing tube, wherein an optical fiber cord formed by accommodating an optical fiber in a reinforcing tube is fixed to the reinforcing tube with an adhesive at a portion near the tip of the optical fiber protruding from the reinforcing tube. Position the part of the optical fiber near the tube tip at the center of the reinforcing tube and fill the vicinity of the tip inside the reinforcing tube with an adhesive to bond the part of the optical fiber near the tube tip to the center of the reinforcing tube. A method for fixing an optical fiber to a reinforcing tube, characterized by fixing. 2. An optical ferrule attachment method, characterized in that an optical ferrule is attached to the optical fiber cord manufactured by the method of claim 1. 3. An optical ferrule attachment method for attaching an optical ferrule to an optical fiber cord manufactured by the method according to claim 1, wherein an adhesive different from the adhesive used for fixing the optical fiber to the reinforcing tube is used. An optical ferrule mounting method characterized in that the optical fiber and the reinforcing tube are fixed to the optical ferrule by inserting the optical fiber of the optical fiber cord and the reinforcing tube into the optical ferrule while being filled in the optical ferrule. 4. The method of attaching an optical ferrule according to claim 3, wherein the optical ferrule is a single-core optical ferrule with a collar. 5. The optical fiber and the stiffening tube of the optical fiber cord are respectively held by a pair of V-grooved holders that can be moved toward and away from each other, and then the end faces of the pair of V-grooved holders are attached to the optical fiber. 2. The reinforcing tube is adhered to a portion of the optical fiber near the tip of the tube in a state in which the tube is somewhat separated in the longitudinal direction.
A method for fixing an optical fiber to a reinforcing tube as described.