JPH0634842A - Production and apparatus for production of optical coupler - Google Patents

Abstract

PURPOSE:To provide the process for production which can automate the contact operation of optical fibers, correspondingly lessens manpower and can produce the fusion stretching type optical coupler having consistent quality with good reproducibility and the apparatus for production of such optical coupler. CONSTITUTION:The parts of two pieces of the optical fibers f installed in parallel, where the coatings are removed, are pressed by contact heads 6a, 6b; 8a, 8b from both sides along the plane formed by two pieces of these optical fibers f in two positions isolated at a prescribed distance. The two fibers f are curved and deformed without generating twists to form the parts in contact with each other in the parts of two pieces of the optical fibers f where the coatings are removed. These contact parts are melted by heating in this state. After the contact parts are integrated by this melting, the contact parts are stretched by melting, by which the optical coupler is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing an optical coupler used for optical communication, optical measurement, etc., and particularly to a method for manufacturing two optical fibers by a melt drawing method. The present invention relates to a method for manufacturing a stretchable optical coupler and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art Optical couplers are widely used for optical communication, optical measurement, etc., but these optical couplers are generally manufactured by a melt drawing method using an optical fiber. When carrying out the melt drawing method, it is necessary to bring the coating removal portions of the two optical fibers arranged in parallel into contact with each other.

Conventionally, as a method for contacting the coating removal portions of two optical fibers with each other, Japanese Patent Laid-Open No. 60-13
As disclosed in Japanese Patent No. 4208, two optical fibers arranged in parallel are fixedly clamped by blocks at two positions separated by a predetermined distance, and the optical fibers are fixed to one block. Release and twist the optical fiber like a braid and re-fix it on the block,
There is a method of bringing the coating removal portions of the two optical fibers into contact with each other.

[0004]

According to the above contact method, the coating removal portions of the two optical fibers can be brought into contact with each other very effectively, and the melt-stretching type optical coupler can be suitably manufactured. However, this method
It is necessary to adjust the twisting position of the optical fiber and manage the tension of the optical fiber so that a certain tension or more is not applied to the optical fiber during the twisting work. At present, it is extremely difficult to automate such tension management, and manual tension management is inevitable.

Further, when manufacturing an optical coupler using a polarization-maintaining fiber by the melt drawing method, it is necessary to contact the optical fibers in parallel without twisting, and the above contact method should be used. I can't.

Therefore, in this case, while observing with a microscope, a method of manually pressing the coating removal portions of the two optical fibers to bring them into contact with each other, or, for example, is described in US Pat. No. 4,632,513. As described above, there is a method in which both sides of the coating removal portion of the two optical fibers are manually contacted with each other by tying them with a string or the like, but both methods are not suitable for contact work depending on the skill level of the operator. There is a problem that variations occur, and accordingly, the excessive loss of the manufactured optical coupler becomes large and the quality becomes unstable.

Therefore, it is an object of the present invention to make it possible to automate the contact work of an optical fiber, thereby saving labor, and moreover, to manufacture a melt-stretch optical coupler of constant quality with good reproducibility. A method and a manufacturing apparatus therefor.

[0008]

The above object can be achieved by an optical coupler manufacturing method and manufacturing apparatus according to the present invention. In summary, according to the present invention, the coating removal portions of two optical fibers installed in parallel are pressed from both sides along a plane formed by the two optical fibers at two positions separated by a predetermined distance. ,
As a result, both optical fibers are deformed into a curved shape without twisting to form the portions in contact with each other in the coating removal portions of the two optical fibers, and in this state, the contact portions are heated. It is a method for producing an optical coupler, which comprises melting and then performing melt drawing after the contact portions are integrated by this melting.

Each of the optical fiber manufacturing methods comprises a first and a second fiber contact device having a base and a pressing means provided on the base. In the pressing means, the pressing means includes first and second support brackets each having a contact head at a tip end thereof, linear guide means for slidably attaching the support brackets to the base, and the support brackets. The present invention is preferably carried out in a manufacturing apparatus characterized by having drive means for driving the support brackets and stopper means for restricting the movement of the support brackets toward the optical fiber and positioning the contact head. It

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method and apparatus for manufacturing an optical coupler according to the present invention will be described below in more detail with reference to the drawings.

A method of manufacturing the optical coupler of the present invention will be described with reference to FIG. According to the present invention, first, a predetermined length,
Usually, two optical fibers f from which the protective coating is removed by a length of about 25 mm are placed in parallel on a commonly used fusion drawing table (not shown).

Next, the optical fibers f installed in parallel
The coating removal portion is horizontally pressed by the first and second pressing means 2 and 4 at two positions separated by a predetermined distance. The first and second pressing means 2, 4 have the same structure, and each pressing means 2, 4 has a pair of contact heads 6a, 6b; 8a, 8b which are configured to be accessible toward each other. Each contact head has a thickness (t) in this embodiment.
Is a rectangular flat plate having a thickness of 3 mm, and various ceramics such as alumina and zirconia can be preferably used. Further, V-grooves 10a, 10b; 12a, 12b are formed in the thickness direction along the axis of the optical fiber f at the pressing portion of each contact head that abuts the optical fiber f. The angle of each V groove can be set arbitrarily, but normally about 90 ° is preferable. The depth of the V groove is the optical fiber f
When the optical fiber f having a cladding diameter of 125 μm is used, the diameter is 100 μm ± 10 μm. Further, the inner surface of the V groove is preferably mirror-finished so as not to damage the pressing optical fiber coating removal portion.

As described above, the coating removal portions of the optical fibers f arranged in parallel are placed at two positions separated by a predetermined distance and along the plane formed by the two optical fibers f by the contact head. From above, a slight bending is applied to the optical fiber f,
Each optical fiber f is deformed in an arc toward each other, and the apex of the maximum deformed portion, that is, the first and second pressing means 2,
The position of the center of 4 is in contact. The degree of contact depends on the first and second pressing means 2,
It can be adjusted by adjusting the pressing amount of 4. Further, the distance between the pressing means 2 and 4 can be arbitrarily set within a range that does not disturb the temperature distribution of the optical fiber heated from the heating source at the time of melt drawing, but generally 11 to 14 m.
m.

According to the present invention having the above structure, the optical fiber f
No torsion stress is applied to the optical fiber f, and the contact of the optical fiber f can be achieved without difficulty by only a slight bending deformation of 60 to 70 μm. This makes it possible to significantly reduce the excess loss of the obtained optical coupler.

While maintaining this contact state, the optical fiber contact portion is heated by a heating source (not shown) to a temperature sufficient for melting the optical fiber, for example, 1600 ° C., and for a predetermined time, for example, about 60 ° C. Hold this state for seconds to 2 minutes. At this time, no tension is applied to the optical fiber f.

As a result, the viscosity of the silica glass forming the cladding of the optical fiber f is lowered, and the surface tension of the silica glass causes the two optical fibers f to move in a direction in which they are in contact with each other. f is completely integrated.

Next, the melt drawing table is driven to pull the optical fiber f in both axial directions to perform melt drawing. The stretching speed is 13 to 100 μm / sec. As a result, the outer diameter of the optical fiber becomes thin and an optical coupler is formed. When the predetermined light branching ratio is obtained, the stretching is stopped and the heating source is removed.

After that, the contact heads 6a, 6b; 8
The a and 8b are moved in the direction away from the optical fiber f (to the position indicated by the alternate long and short dash line in FIG. 1), and in this state, the optical fiber f is fixed to the glass substrate with resin. The resin coupler-completed optical coupler is removed from the melt drawing table, and a new optical fiber is set on the melt drawing table in order to manufacture the next optical coupler.

The excess loss of the optical coupler manufactured in this way could be 0.1 dB or less. The temperature characteristics were also good, and the branching ratio variation was within ± 2% in the range of + 40 ° C to -20 ° C.

Next, with reference also to FIGS. 2 and 3, an embodiment of a manufacturing apparatus capable of suitably carrying out the method of manufacturing an optical coupler according to the present invention will be described.

In this embodiment, the optical coupler manufacturing apparatus 1 of the present invention is used.
Is composed of first and second fiber contact devices 20, 40 provided with the first and second pressing means 2, 4. Since the first and second fiber contact devices 20 and 40 have the same configuration, the first fiber contact device 2
0 will be described.

The fiber contact device 20 is carried by a horizontal moving means 100 (FIG. 3), such as an XY table or a one-way slider, which is well known to those skilled in the art, and is shown in FIG. , A base 21 that is slidable along the axial direction of the optical fiber f. Horizontal moving means 10
0 can also be attached to a melt drawing table.

The pressing means 2 fixes the pair of contact heads 6a and 6b to the tip end portions thereof, respectively.
It has support brackets 22 and 23. The support brackets 22 and 23 are slidably carried by the linear guide 24 provided on the base 21 via linear guide bearings 25 and 26, respectively. In this embodiment, the linear guides 24 are arranged in a manner orthogonal to the axial direction of the optical fiber f, and therefore the support brackets 22, 2 are provided.
The contact heads 6a and 6b held by the unit 3 can approach the optical fiber f in a manner orthogonal to each other. Further, in the present embodiment, both support brackets 22 and 23 are configured to be carried by one linear guide 24, but they may be carried by separate linear guides.

At the end of the first support bracket 22 opposite to the end to which the contact head 6a is fixed, the operating member 2 is provided.
2a are integrally formed, and drive means 27 such as an air cylinder is connected to the 2a. The air cylinder 27 is fixed to the base 21 by a mounting base 28. Further, a stopper means 29, which is a micrometer in this embodiment, is arranged facing the actuating member 22a. This micrometer 2
When the first support bracket 22 is driven by the air cylinder 27 and approaches the optical fiber f, the head abuts the actuating member 22a so that the first support bracket 22, that is, the contact head. 6a functions to regulate and position the movement of 6a in the optical fiber direction. The micrometer 29 is fixed to the base 21 by a mounting base 30.

Similarly, of the second support bracket 23,
The actuating member 23a is also integrally formed at the end opposite to the end to which the contact head 6b is fixed, and the driving means 31 such as an air cylinder is connected thereto. This air cylinder 31
Are fixed to the base 21 by the mount 30.
Further, the stopper means 3 is faced to the operating member 23a.
2. In this embodiment, a micrometer is arranged. When the second support bracket 23 is driven by the air cylinder 31 and approaches the optical fiber f, the head of the micrometer 32 comes into contact with the actuating member 23a so that the second support bracket 23 is That is, it functions to regulate the movement of the contact head 6b in the optical fiber direction and to position it. The micrometer 32 is fixed to the base 21 by a mount 33.

With the above structure, first, the first and second support brackets 22 and 2 are attached to both the micrometers 29 and 32.
The gap between the contact heads 6a and 6b is adjusted by restricting the movement of the optical fiber 3 in the direction of the optical fiber, and the good contact of the optical fiber f is realized with good reproducibility without any adjustment after the second time. can do. According to the present invention, the gap between the contact heads 6a and 6b can be set within an error range of 2 μm or less.
Of course, when the contact heads 6a and 6b are attached to the support brackets 22 and 23, the respective V-grooves 10 are attached.
The a and 10b are adjusted so as to abut on the optical fibers f arranged in parallel within a plane defined by the optical fibers f. This adjustment is preferably adjusted so that the level difference between both V grooves is within 10 μm.

The second fiber contact device 40 having the second pressing means 4 is also the second fiber contact device 20.
It is constructed in the same way as.

[0028]

As described above, in the optical coupler manufacturing method according to the present invention, the coating removing portions of the two optical fibers arranged in parallel are separated from each other at a predetermined distance from both sides. By pressing, the two optical fibers are deformed into a curved shape without twisting to form the portions in contact with each other in the coating removal portions of the two optical fibers, and in this state, the contact portions are heated. By melting,
Since the melt drawing is performed after the contact portions are integrated by this melting, the contact work of the optical fiber can be automated, which saves labor and, in addition, the melt drawing type optical coupler of constant quality. Can be manufactured with good reproducibility. Further, the optical coupler manufacturing apparatus of the present invention,
Optical fiber contact can be achieved with good reproducibility, and labor can be saved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining an optical coupler manufacturing method according to the present invention.

FIG. 2 is a plan view of an embodiment of an optical coupler manufacturing apparatus according to the present invention.

FIG. 3 is a front view of the optical coupler manufacturing apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical coupler manufacturing apparatus 2, 4 Pressing means 6a, 6b, 8a, 8b Contact head 21 Base 22, 23 Support bracket 24, 25, 26 Linear guide means 27, 31 Driving means 29, 32 Stopper means

Claims (2)

[Claims] 1. A coating removing portion of two optical fibers installed in parallel is provided at two positions separated by a predetermined distance.
Pressing from both sides along the plane formed by the two optical fibers, whereby the two optical fibers are deformed into a curved shape without twisting to form a portion in contact with each other at the coating removal portion of the two optical fibers. Then, in this state, the contact portion is heated to be melted, and the contact portion is integrated by this melting, and then melt-stretching is performed. 2. Each of the first and second fiber contact devices is provided with a base and a pressing means provided on the base, and in each of the fiber contact devices, the pressing means comprises: First and second support brackets each provided with a contact head at the tip, linear guide means for slidably attaching each support bracket to the base, and drive means for driving each support bracket, An optical coupler manufacturing apparatus comprising: stopper means for restricting the movement of each of the support brackets toward the optical fiber and for positioning the contact head.