JPH0720343A - Production of optical fiber coupler - Google Patents

Abstract

PURPOSE:To provide the process for industrial production of the optical fiber coupler which is small in the size of an optical fiber coupler body and is small in dependency of an optical branching ratio on polarized light at a good yield. CONSTITUTION:This process for production of the optical fiber coupler comprises in forming plural points of coupling parts by bringing plural pieces of optical fibers 20 into contact with each other and simultaneously heating, fusing and stretching the plural points of the contact points thereof. The middle part where plural pieces of the optical fibers 20 is in contact with each other are fixed by a fixing stage 14. Both side parts succeeding to the fixing part are heated and are stretched by clamping the parts which are reverse from the fixing part and succeed to these heated parts with moving stages 2, 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber coupler used in optical communication systems, sensor systems and the like.

[0002]

2. Description of the Related Art In an optical communication system, an optical fiber coupler is used as an important component for branching / coupling or splitting / combining light. In particular, an optical fiber coupler obtained by processing an optical fiber has excellent coupling properties with the optical fiber and has a low loss of passing light, and is therefore used in many fields.

FIG. 3 is an external view of a fusion splicing apparatus for carrying out a conventional optical fiber coupler manufacturing method.

In this fusion bonding apparatus, a stage guide groove 5 is formed in the center of a base 4, and a stage feed screw rod 7 is rotatably arranged in the stage guide groove 5. The first and second stretching movement stages 2 and 3 are provided on a base 4, and sliding protrusions 8 project from the lower surface and are fitted in the stage guide groove 5. The sliding protrusion 8 is provided with a female screw hole and is screwed into the stage feed screw rod 7. A fastening plate 9 is screwed to the upper ends of the first and second stretching movement stages 2 and 3.

A burner installation board 13 having a movable burner 1 for discharging an oxyhydrogen flame is provided between the first and second stretching movement stages 2 and 3. A burner guide groove 11 is formed on the burner installation board 13, and the movable burner 1 has a burner sliding projection 12 that opens a female screw hole. The burner sliding projection 12 is formed in the burner guide groove 11.
And is screwed with a burner feed screw rod (not shown) through a female screw hole.

An optical fiber coupler is manufactured in the following manner using this fusion device.

Two optical fibers are bundled and fixed by the fastening plates 9 of the first and second stretching movement stages 2 and 3 which are kept at a predetermined distance. The end of one optical fiber of the optical fiber bundle 20 is connected to the laser light source 21, and the end of the other optical fiber is connected to the light quantity measuring device 22. The movable burner 1 is ignited, and the reversible motor 10 is continuously and alternately rotated forward and backward to cause the movable burner 1 to reciprocate along the burner guide groove 11.

The amount of incident light of the laser light source 21 appearing at the end of another optical fiber is observed by the light amount measuring device 22, and
An optical fiber bundle 20 is provided between the second stretching movement stages 2 and 3.
The stage motor 6 is rotated from the time point when the partial fusion starts, and the optical fiber bundle 20 is extended by running the first and second extension movement stages 2 and 3 in the directions in which they are separated from each other. The quantity of light observed by the light quantity measuring device 22 is 5
When it reaches 0%, the stage motor 6 is stopped and the extension of the optical fiber bundle 20 is stopped.

If the optical fiber coupler manufactured as described above (see FIG. 4) is an optical fiber coupler that splits the light intensity of the incident light into two, the length of the coupling portion 17 is about 11 mm. In addition, an optical fiber coupler (WD that splits and splits two wavelengths)
In the case of M coupler), the length is about 40 mm, and the optical fiber coupler body becomes large. Further, in the WDM coupler, the polarization dependence of the optical coupling / branching ratio was as large as 10%.

[0010]

In the conventional method for manufacturing an optical fiber coupler, since the manufactured optical fiber coupler body is large, the entire system using the optical fiber coupler as one component becomes large. . Since the optical fiber coupler is one component used in an optical communication system, a sensor system, etc., its size should not be large. In JP-A-5-19136, a plurality of optical fibers are twisted together to manufacture an optical fiber coupler having a small size, but it is difficult to industrially manufacture the optical fiber coupler with a high yield.

The present invention has been made to solve the above-mentioned problems, and provides an industrial manufacturing method in which the main body of an optical fiber coupler is made small and the yield of the optical fiber coupler having a small polarization dependence of the optical coupling / branching ratio is good. The purpose is to

[0012]

The method for manufacturing an optical fiber coupler according to the present invention, which has been made to achieve the above object, comprises:
As shown in FIG. 1, it is a method of manufacturing an optical fiber coupler in which a plurality of optical fibers 20 are brought into contact with each other, and a plurality of contact portions are simultaneously heated, fused, and stretched to form a plurality of joint portions, The part where the plural optical fibers are in contact with each other is fixed by the fixed stage 14, the parts on both sides following the fixed part are heated, and the part opposite to the fixed part and following the heated part is moved. Draw and stretch in stages 2-3.

[0013]

The plurality of optical fibers 20 are aligned in parallel, the optical fiber bundle 20 is fixed substantially at the center by the tightening plate 9 of the fixed stage 14, and the first and second extending portions located on both sides of the fixed stage 14 are fixed. The fastening plates 9 of the moving stages 2 and 3 are fixed at a plurality of positions to maintain parallelism. As shown in FIG. 2, the optical fiber bundle 20 is heated, fused, and stretched at a plurality of positions between the fixed stage 14 and the first and second stretching / moving stages 2 and 3, so that a plurality of joints are formed. The optical fiber coupler has the parts 15 and 16.

[0014]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is an external view of a fusion splicer for carrying out the method of manufacturing an optical fiber coupler to which the present invention is applied.
In this fusion splicing apparatus, the optical fiber bundle 20 is fixed at a substantially central portion thereof by a fixed stage 14, and the optical fiber bundle 20 is heated by a movable burner 1 at two locations on both sides of the central portion, so that It is a device for extending the optical path of the optical fiber by extending with the second extension moving stage 3.

A stage guide groove 5 is formed in the center of the base 4, and a stage motor 6 is installed at the end of the upper surface. A stage feed screw rod 7 is rotatably arranged in the stage guide groove 5. The stage feed screw rod 7 has a left screw on one side and a right screw on the other side with the center in the length direction as the center. The tip of the central axis of rotation of the stage feed screw rod 7 is linked to the stage motor 6 by a gear. The first and second stretching movement stages 2 and 3 and the fixed stage 14 are provided on the base 4, and the sliding projections 8 project from the lower surface and are fitted into the stage guide groove 5.
The sliding protrusion 8 is provided with a female screw hole. The sliding protrusion 8 allows the first extension moving stage 2 to be screwed into the left screw of the stage feed screw rod 7, and the second extension moving stage 3 to be the right screw. It is screwed. The first and second stretching movement stages 2,
A fastening plate 9 is screwed to the upper ends of the fixed stage 14 and the fixed stage 3.

A burner setting board 13 having movable burners 1 for discharging an oxyhydrogen flame is provided at two locations between the fixed stage 14 and the first and second stretching movement stages 2 and 3. A reversible motor 10 is installed on the upper surface of the burner installation board 13, and a burner guide groove 11 is installed directly above the stage guide groove 5 in parallel. A burner feed screw rod (not shown) is rotatably arranged in the burner guide groove 11, and the burner feed screw rod is a reversible motor 10.
It interlocks with the gear in between. The movable burner 1 has a burner sliding protrusion 12 that opens a female screw hole. The burner sliding protrusion 12 is fitted in the burner guide groove 11 and is screwed with the burner feed screw rod by the female screw hole. .

A laser light source 21 for injecting a laser beam into an optical fiber and a light amount measuring device 22 for measuring the amount of light emitted from the optical fiber are provided near the base 4.

An optical fiber coupler is manufactured in the following manner using this fusion device.

The two optical fibers are bundled together, and the fixed stage 14 at the substantially central portion of the optical fiber bundle 20 and the first and second stretching movement stages 2 and 3 which are kept at a predetermined distance from the fixed stage 14. The three fastening plates 9 are used to fix the three places. The end of one optical fiber of the optical fiber bundle 20 is connected to the laser light source 21, and the end of the other optical fiber is connected to the light quantity measuring device 22, and the target branching ratio of light at the fused portion is set to 50%. To do. The two movable burners 1 are ignited, and the reversible motor 10 is continuously and alternately rotated forward and backward to cause the movable burner 1 to reciprocate along the burner guide groove 11.

The amount of the incident light of the laser light source 21 appearing at the end of another optical fiber is observed by the light quantity measuring device 22, and the optical fiber between the fixed stage 14 and the first and second extension moving stages 2 and 3 is measured. The stage motor 6 is rotated from the time point when the bundle 20 starts to be partially fused, and the first and second stretching movement stages 2 and 3 are caused to travel in a direction away from the fixed stage 14 to move the optical fiber bundle 20. Stretch at two points. When the amount of light observed by the light amount measuring device 22 reaches 50% of the incident light, the stage motor 6 is stopped and the optical fiber bundle 2
Stop stretching 0.

The optical fiber coupler manufactured in this manner has a shape as shown in FIG.
The length of 16 was reduced by about 20% from the conventional one. Furthermore, when a WDM coupler is manufactured by the above method,
When the polarization dependence of the optical coupling / branching ratio of the coupler was measured, it was 2
% Was less than%.

[0023]

As described above in detail, according to the method for manufacturing an optical fiber coupler of the present invention, the total length of a plurality of coupling portions of the optical fiber coupler is shorter than that of the conventional optical fiber coupler body. Can be manufactured smaller than before, and the size of the entire system using the optical fiber coupler as one component can also be reduced. Further, in an optical fiber coupler, particularly a WDM coupler, it is possible to industrially manufacture an optical fiber coupler having a small polarization dependency of the optical coupling / branching ratio with a high yield.

[Brief description of drawings]

FIG. 1 is an external view of a fusion splicing device for carrying out a method for manufacturing an optical fiber coupler to which the present invention is applied.

FIG. 2 is a schematic view of an optical fiber coupler manufactured by a method for manufacturing an optical fiber coupler to which the present invention is applied.

FIG. 3 is an external view of a fusion splicing device for carrying out a conventional optical fiber coupler manufacturing method.

FIG. 4 is a schematic view of an optical fiber coupler manufactured by a conventional method for manufacturing an optical fiber coupler.

[Explanation of symbols]

1 is a movable burner, 2 is a first extension movement stage, 3 is a second extension movement stage, 4 is a base, 5 is a stage guide groove,
6 is a stage motor, 7 is a screw rod, 8 is a sliding protrusion, 9 is a tightening plate, 10 is a reversible motor, 11 is a burner guide groove, 12 is a burner sliding protrusion, 13 is a burner installation board,
14 is a fixed stage, 15/16/17 is a coupling part, 20
Is an optical fiber bundle, 21 is a laser light source, and 22 is a light quantity measuring device.

Claims (1)

[Claims] 1. A method for manufacturing an optical fiber coupler, which comprises contacting a plurality of optical fibers and simultaneously heating, fusing, and stretching a plurality of contacting points to form a plurality of coupling sections. The part where the optical fiber is in contact is fixed with a fixed stage, the parts on both sides following the fixed part are heated, and the part opposite to the fixed part and following the heated part is held with a moving stage. A method for manufacturing an optical fiber coupler, which comprises stretching.