JPH07168052A - Optical fiber coupler reinforcing method - Google Patents

Abstract

PURPOSE:To maintain the allowable bending radius of an optical coated fiber and prevent the light input loss and the optical coated fiber from being damaged by bending an optical fiber from both ends or one end of a reinforcing part. CONSTITUTION:An optical fiber which comes out of both ends of a reinforcing part 2 is bent like an arc to shorten the length of the part to be stored. The fiber storage part 12 at both ends of the reinforcing part 2 is formed like an arc in an attachment direction of an optical coated fiber 1 and the allowance bending radius R of the coated part 1b of the optical coated fiber is kept within a prescribed range. In that case, the optical coated fiber 1 is fixed to the reinforcing part 2 with a primary adhesive 4a and a secondary adhesive 4b. To firmly fix the optical coated fiber 1 in the reinforcing part 2, any adhesive means may be employed as long as both the wire and the part 2 are sufficiently united and only one point adhesion may be acceptable. However, it is preferable to employ a two points-adhesion way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing an optical fiber having an optical fiber core from a reinforcing member such as an optical fiber coupler. In particular, in the method of reinforcing an optical fiber coupler according to the present invention, the minimum allowable bending diameter of the fiber can be maintained by making the optical fiber emerging from the reinforcing member into an arc shape. Line damage can be prevented, and the storage space when modularizing the optical fiber coupler can be reduced.

[0002]

2. Description of the Related Art Conventionally, when an optical fiber is heated, fused and drawn, and a tensile force is applied to the optical fiber, the work is generally performed in a straight line (Japanese Patent Publication No. 3-18540).
No. 6). In addition, the fusion spliced portion of the optical fiber core wire needs to be protected from external factors by a reinforcing member. These conventional reinforcing members generally have the structure shown in FIG. 6, (a) is a perspective view of the reinforcing member, and (b) is a schematic cross-sectional view thereof.

[0003]

The optical fiber coupler is
It is used by connecting with optical connection parts such as optical fiber filters having other optical fibers, optical connectors, and optical switches. Therefore, a required length of the optical fiber core wire is required on both sides of the reinforcing member of the optical fiber coupler.

Further, when modularized, it is quite conceivable that the bending radius will be smaller than the allowable bending radius of the optical fiber core at the exit from the reinforcing member, and the same occurs during handling. Therefore, there is a problem that deterioration of optical insertion loss and disconnection occur. Since it is necessary to process the optical fiber core wire from the optical fiber coupler with extra length and store it while suppressing it to a certain curvature, the length of the storage tends to be longer than the length of the optical fiber coupler. .

[0005]

Means for Solving the Problems As a result of various studies on the above-mentioned problems, the inventor of the present invention can bend an optical fiber core from an optical fiber coupler in a desired direction in advance.
The inventors have found that the length of the storage portion can be shortened, and have completed the present invention.

That is, according to the present invention: In a method of manufacturing an optical fiber coupler, wherein at least two optical fibers are heated and fusion-stretched, a tensile force is applied to the optical fibers, and then the optical fibers are fixed to the reinforcing member, Provided is a method for reinforcing an optical fiber coupler in which an optical fiber is bent from both ends or one end. Another feature is that both ends or one end of the fiber storage portion of the reinforcing member is formed in an arc shape in the optical fiber mounting direction. Another feature is that a jig for fixing the optical fiber is used at a portion where both ends or one end of the fiber housing portion of the reinforcing member is formed in an arc shape in the optical fiber mounting direction. Also,

Another feature is that the optical fiber holder is provided along the arcuate portion of the fiber storage portion. Another feature is that both ends or one end of the reinforcing member have optical fiber outlet portions formed in a bellmouth shape. Another feature is that rotary elbows are provided at both ends or one end of the reinforcing member. Another feature is that a recess is provided on the outer periphery of the reinforcing member in a direction perpendicular to the mounting of the optical fiber. It is also characterized in that the curvature of the arc-shaped portion of the fiber storage portion is 30 mm or more.

The present invention will be described in detail below.

According to the reinforcing member of the optical fiber coupler of the present invention, (1) the reinforcing member is bent in an arc shape so as to correspond to the permissible bending diameter R of the optical fiber at the optical fiber outlets at both ends or one end of the reinforcing member. By using a member and bending the optical fiber core in an arc shape, it is possible to prevent serious accidents such as an increase in optical insertion loss and damage to the optical fiber even when the optical fiber is modularized.

(2) When the reinforcing member of the optical fiber coupler of the present invention is used, the storage space can be made smaller than that of the conventional reinforcing member. For example, FIG. 7 is a schematic diagram comparing the reinforcing member (a) of the conventional optical fiber coupler with the reinforcing member (b) of the optical fiber coupler of the present invention.
In this case, the allowable bending diameter (curvature) R of the optical fiber is 3
When it is 0 mm or more, the reinforcing effect of the optical fiber coupler can be improved.

(3) By providing a concave portion as shown in FIG. 5 for fixing the optical fiber coupler on the outer periphery of the reinforcing member, for example, rotation at the time of modularization or movement in the optical fiber mounting direction. It can be easily prevented.

[0011]

The present invention is illustrated in detail by the following examples, which do not limit the scope of the present invention. Figure 1
It is a schematic diagram which shows the state which bent the optical fiber which goes out from both ends of a reinforcement member in circular arc shape, and shortened the length of the storage part. FIG. 1- (a) shows that the fiber housing portions 12 at both ends of the reinforcing member 2 are formed in an arc shape in the mounting direction of the optical fiber core wire 1, and the allowable bending radius R of the coating portion 1b of the optical fiber core wire is within a certain range. It is sectional drawing which shows the state maintained. In that case, the optical fiber core wire 1 is attached to the reinforcing member 2 by the primary bonding 4a and the secondary bonding 4b.
It is fixed at and.

For more secure fixing of the optical fiber core wire and the reinforcing member, any bonding method and one-point bonding may be used as long as they are sufficiently bonded, but such a two-point bonding method is adopted. desirable.

FIGS. 1- (b) and 1- (c) are schematic views showing a concrete mode for fixing the optical fiber core wire and the reinforcing member shown in FIG. 1- (a). In FIG. 1- (B), the bare fiber 1a needs to be primary-bonded 4a with a constant tensile force applied. At this time, the covering portion 1b
It also requires a certain amount of adhesion.

FIG. 1- (c) is a schematic view of a concrete mode showing the case where the holding jig 5 is used. At this time, the holding jig 5 is used to attach the covering portion 1b to the allowable radius R of the groove bottom portion 12 to help the secondary bonding 4b. At this time, if a release agent is attached to the holding jig 5 in advance, the work becomes easy. FIG. 1- (d) is a perspective view showing an example of a specific structure of the holding jig 5.

FIG. 2 is a schematic view showing another mode in which the holding plate 6 is used to bend the optical fibers extending from both ends of the reinforcing member in an arc shape to shorten the length of the housing portion. Figure 2-
In (a), after the primary adhesion 4a is performed as in FIG. 1- (b), the covering portion 1b is suppressed to the allowable bending diameter R of the fiber accommodating portion 12 by the holding plate 6, and at the same time, the secondary adhesion 4b is slightly applied. It is a schematic diagram which shows the aspect integrated with the reinforcing member 2 by doing so. FIG. 2- (B) is a perspective view showing an example of a specific structure of the holding plate 6.

FIG. 3 is a schematic view showing another mode of bending the optical fiber extending from both ends of the reinforcing member into an arc shape. Figure 3
-(A): The reinforcing portion 2 and the upper lid 3 are integrated to form an integral reinforcing member 7, and bellmouth-shaped curved portions 7a are provided at both ends thereof, and the curvature of the curved portion 7a is set to the allowable bending diameter of the covering portion 1b. R
To match. In this case, the adhesive 4 need only be the primary adhesive 4a. Since the integral reinforcing member 7 has a bell-mouth shape, the covering portion 1b can support all directions. Figure 3-
(B) is a perspective view showing an example of a specific structure of the integrated reinforcing member 7 including the bellmouth-shaped curved portion 7a.

FIG. 4 is a schematic view showing another embodiment of the integral reinforcing portion in which the rotary elbow is provided on the integral reinforcing member shown in FIG. In FIG. 4, the rotary elbow 8 is linked to both ends of the integral reinforcing member, and the allowable bending diameter R of the covering portion 1b is R.
To protect the strength. Therefore, the covering portion 1b can support all directions. Further, a fixed gap, that is, the inner diameter d of the elbow, is provided between the covering portion 1b and the rotary elbow 8 so that the optical fiber is not twisted during rotation.

FIG. 5 is a schematic view showing another embodiment of the integrated reinforcing member in which a recess is provided on the outer circumference of the integrated reinforcing member. In FIG. 5, a concave portion 2a is provided on the outer periphery of the integrated reinforcing member,
Make it easy to fix with a fixing band etc. when modularizing. Further, by doing so, the allowable bending diameter of the covering portion 1b can be maintained and protected, and the reinforcing portion 2 can be fixed easily.

In the present invention, by adopting the reinforcing method of the optical fiber coupler shown in FIGS.
-It is possible to obtain the effect of not lowering the quality characteristics of the optical fiber coupler as compared with the reinforcing member of the conventional optical fiber coupler as shown in (a).

[0020]

As is apparent from the above description, according to the present invention, optical insertion loss and damage to the optical fiber core can be prevented by maintaining the allowable bending diameter of the optical fiber core. Further, there is an effect that the storage space can be reduced when the optical fiber coupler is modularized.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state in which an optical fiber extending from both ends of a reinforcing member is bent into an arc shape and a length of a storage portion thereof is shortened. FIG. 1- (a) is a cross-sectional view showing a state in which an optical fiber core wire is formed in an arc shape with a curvature R from both ends of the reinforcing member and is fixed to the reinforcing member by an adhesive at two points. Figure 1-
(B) and (C) are schematic views showing a specific mode for fixing the optical fiber core wire and the reinforcing member. Figure 1-
(D) is a perspective view showing an example of a specific structure of a holding jig.

[FIG. 2] Using the pressing plate, bend the optical fiber into an arc shape,
It is the schematic which shows the other aspect which shortens the length of the storage part. FIG. 2- (A) is a schematic view showing a mode of the integrated reinforcing member after the primary bonding, the covering portion is suppressed to the curvature R by the pressing plate, and the secondary bonding 4b is performed. FIG. 2- (B) is a schematic view showing an example of a specific structure of the holding plate.

FIG. 3 is a schematic view showing another mode of bending an optical fiber extending from both ends of a reinforcing member into an arc shape. Figure 3- (a)
It is sectional drawing of the integral-type reinforcement member which provided the bell mouth-shaped curved part. FIG. 3- (B) is a perspective view showing the specific structure.

FIG. 4 is a schematic view showing an integral type reinforcing member provided with a rotary elbow.

FIG. 5 is a perspective view showing a state in which a concave portion is provided on the outer periphery of the integrated reinforcing member.

FIG. 6- (a) is a perspective view of a reinforcing member of a conventional optical fiber coupler, and FIG. 6 (b) is a schematic cross-sectional view thereof.

FIG. 7 is a schematic diagram comparing the reinforcing member (a) of the conventional optical fiber coupler and the reinforcing member (b) of the optical fiber coupler of the present invention in terms of the allowable bending diameter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 1a Optical fiber core wire (bare fiber) 1b Covering part 2 Reinforcing member 2a Recessed portion 3 Upper lid 4 Adhesive 4a Primary adhesion 4b Secondary adhesion 5 Holding jig 6 Holding plate 7 Integrated reinforcing member 7a Bellmouth curved section 8 Rotary Elbow 9 Fusion Drawing Section 10 Optical Fiber Coupler 11 Fusion Drawing Section Length 12 Fiber Storage Section R Allowable Bending Diameter d Elbow Inner Diameter

Claims (8)

[Claims] 1. A method for manufacturing an optical fiber coupler in which at least two optical fibers are heated, fused and stretched, a tensile force is applied to the optical fibers, and then the optical fibers are fixed to a reinforcing member, from both ends or one end of the reinforcing member. A method for reinforcing an optical fiber coupler, which comprises bending an optical fiber. 2. The reinforcing method for an optical fiber coupler according to claim 1, wherein both ends or one end of the fiber housing portion of the reinforcing member is formed in an arc shape in the optical fiber mounting direction. 3. A jig for fixing an optical fiber to a portion where both ends or one end of a fiber storage portion of a reinforcing member is formed in an arc shape in the optical fiber mounting direction is used. Reinforcing method of optical fiber coupler. 4. The method of reinforcing an optical fiber coupler according to claim 2, wherein an optical fiber retainer is provided along an arcuate portion of the fiber storage portion. 5. The method of reinforcing an optical fiber coupler according to claim 1, wherein the optical fiber outlet portions at both ends or one end of the reinforcing member are formed in a bell mouth shape. 6. The method of reinforcing an optical fiber coupler according to claim 1, wherein rotary elbows are provided at both ends or one end of the reinforcing member. 7. The reinforcing method for an optical fiber coupler according to claim 1, wherein a recess is provided on the outer periphery of the reinforcing member in a direction perpendicular to the mounting of the optical fiber. 8. The curvature of the arc-shaped portion of the fiber storage portion is set to 3
The method for reinforcing an optical fiber coupler according to any one of claims 2 to 4, wherein the method is 0 mm or more.