JPH077137B2 - Optical fiber cutlet manufacturing equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber coupler manufacturing apparatus, and more particularly to an apparatus for improving the alignment accuracy of optical fibers during the manufacturing process and reducing the bending that occurs during fusion. Is.

[Prior Art] An optical fiber coupler is an element having a function of branching and joining light. FIGS. 3 (1) to 3 (3) show a process for producing an optical fiber coupler by fusion drawing. FIG. 3 shows the case where two optical fibers are used, but the same applies to the case where two or more optical fibers are used. First (1) Two optical fibers 3
Align the fused parts of 1,32 in parallel and close to each other. 33 is the core. Then, (2) a part of the longitudinal direction is heated to fuse a part of the two optical fibers 31 and 32. Reference numeral 34 is a fused portion. In (3), tension is applied to the optical fibers 31 and 32 while heating the fusion-bonded portion 34, and stretching is performed. As a result, in the fusion extending section 35, the cores 33, 33 of the optical fibers 31, 32, respectively.
Since the distance between them decreases and the core diameter and the outer diameter of the optical fiber decrease, light coupling occurs between the cores 33, 33. Then, the stretching is stopped when the desired optical coupling is obtained. For example, a coupler manufacturing apparatus has been proposed in Japanese Patent Application No. 59-88168 (Japanese Patent Laid-Open No. 60-232515). However, in the conventional apparatus, the step of aligning and aligning the optical fibers shown in FIG. Fourth
This is done using the device shown in the figure. The optical fibers 41, 42 pass through vertical position adjusting devices 44, 44a and horizontal position adjusting devices 45, 45a on the drawing tables 47, 47a, and optical fiber fixing devices 46a, 46b, 46c,
It is fixed with a certain tension by 46d. 43 and 43a are temporary fixing devices.

FIG. 5 shows an enlarged view of the vertical position adjusting device 44 and the horizontal position adjusting device 45. The vertical position adjusting device 44 has a groove slightly deeper than the fiber diameter, so that the optical fibers 41 and 42 are adjusted on a plane having substantially the same height. The horizontal position adjusting device 45 has a structure in which the optical fibers 41 and 42 are sandwiched from the horizontal direction.
To move the optical fibers 41 and 42 close to each other. There is a similar mechanism on the other extension table 47a, and the optical fiber 4
1, 42 will be aligned closely from parallel, and after being aligned, they are fixed to the drawing stands 47, 47a by the optical fiber temporary fixing devices 43, 43a, and the fusion process is performed.

However, in the fiber position adjusting method as shown in FIG. 4, the optical fiber fixing device 46a, 46b, 46c, 46d is provided with the optical fiber 4.
There is a difference in tension applied to the optical fibers 41 and 42 when the fibers 1 and 42 are fixed. In addition, horizontal position adjustment device 45,4
By adjusting the position by 5a, the optical fiber 41 is moved to the drawing tables 47, 4
On 7a, because it is moved in the direction of the optical fiber 42,
New tension is added. As a result, the optical fiber temporary fixing device 4
With the optical fibers 41 and 42 fixed by 3,43a,
The tension applied to the optical fiber 41 and the tension applied to the optical fiber 42 are different. When a part of the optical fibers 41, 42 in the longitudinal direction is heated and melted in this state, and fusion is performed, the tension is released in the molten state, so that the tension applied to the optical fibers 41, 42 is different, Bending and twisting occur at the fused portion as shown in FIG.

[Problems to be Solved by the Invention] Such bending and twisting in the fused portion causes an increase in insertion loss of the optical fiber coupler, and since the bending state is not constant, the optical fiber coupler cannot be manufactured. There is a problem that the reproducibility is reduced.

An object of the present invention is to provide an apparatus that can reproducibly manufacture a low-loss optical fiber coupler by significantly reducing the tension difference applied to the optical fiber when the position of the optical fiber is adjusted.

[Means for Solving the Problems] In order to achieve such an object, in the present invention, a part of a plurality of optical fibers in the longitudinal direction are heated and fused to each other and stretched to manufacture an optical fiber coupler. In the optical coupler manufacturing apparatus, a plurality of movable bases that fix a part of each of the plurality of optical fibers and are movable in the longitudinal direction of each optical fiber, and drive the movable bases to cover the plurality of optical fibers. And a drive mechanism for making the tensions substantially equal to each other.

[Operation] According to the present invention, in the position adjusting step during the manufacturing process of the optical fiber coupler, the tension applied to each of the optical fibers is made uniform by fixing the optical fibers to the movable table to which a constant force is applied. The position of the optical fiber can be adjusted in this state, and the bending of the fused part during fusion,
Torsion can be significantly reduced.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining an embodiment of the present invention. In the figure, 1 and 2 are optical fibers, 3, 3a is a drawing table, 4, 4a are optical fiber temporary fixing devices, 5 and 5a are vertical position adjusting devices, 6 and 6a are horizontal position adjusting devices, and 7 and 7a are optical devices. A fiber fixing device, 8 and 8a are movable bases, 9 is a wire, 10 is a pulley, and 11 is a weight.
FIG. 2 shows the positional relationship among the moving table 8, 8a, the wire 9, the pulley 10 and the weight 11. 12 is an air supply pipe. In the optical fiber position adjusting step, one end of each of the optical fibers 1 and 2 is fixed to the optical fiber fixing base 7, 7a, and the other end is fixed to the moving base 8, 8a. The moving tables 8 and 8a use air bearings, and the moving tables are floated by gas pressure and can move in the longitudinal direction of the optical fibers 1 and 2. The moving table 8, 8a is a wire 9
Is connected to the weight 11, and the movable bases 8 and 8a receive a constant pulling force due to the gravity applied to the weight 11, but they are stationary at the balance position by the optical fibers 1 and 2. At this time, almost uniform tension is applied to the optical fibers 1 and 2. Even if the optical fibers 1 and 2 are deviated from their original fixed positions by the vertical position adjustment devices 5 and 5a and the horizontal position adjustment devices 6 and 6a, the positions of the movable bases 8 and 8a change according to the deviations, and the optical fibers There is no change in the tension applied to 1 and 2. In this state, the position adjusting process is completed, and the optical fibers 1 and 2 are temporarily fixed to the optical fiber temporary fixing devices 4 and 4a. At that time, the tension applied to the optical fibers 1 and 2 is a value determined by the weight of the weight 11, and is substantially equal. For this reason, bending and twisting at the fusion-bonded portion in the fusion-bonding process of the prior art hardly occur.

In this embodiment, the relative refractive index of the core and the cladding is 0.3%,
Using a fiber with a cutoff wavelength of 1.1 μm, a wavelength of 1.3 μm
When a 3 dB coupler was produced at m, the excess loss was 0.1
An optical fiber coupler of dB or less could be manufactured with a reproducibility of almost 100%. Excess loss of 0.1d with conventional manufacturing method
The yield of B or less was about 30%, and the yield was greatly improved.

The reason why the air bearing is used for the moving base in this embodiment is to reduce the friction applied to the moving base, and the moving base using mechanical bearings and the magnetic levitation type moving base, which have relatively small friction, are similarly used. Of course, it can be used. In addition, as a driving force for the movable table, it is needless to say that not only a weight but also an electromagnetic force such as a differential transformer or a linear motor, or an elastic force such as a spring can be used.

As an example, an example in which the number of optical fibers used in the optical fiber coupler is shown. However, in the case of using two or more optical fibers, the moving table and the optical fibers are selected according to the number of optical fibers. A fixed base may be installed.

It goes without saying that the present invention can be applied to the production of all kinds of optical fiber couplers by the fusion drawing method.

[Effects of the Invention] As described above, the position of the optical fiber can be adjusted while the tension applied to each of the optical fibers used for manufacturing the optical fiber coupler is equalized, and when the fusion is performed. Bending and twisting of the fused portion of can be greatly reduced. Therefore, there is an advantage that the yield of manufacturing the optical fiber coupler with low loss can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, FIG. 3 is a diagram showing a process for producing an optical fiber coupler by a fusion drawing method, and FIG. FIG. 5 is a configuration diagram of a conventional manufacturing apparatus, FIG. 5 is an enlarged view of a vertical position adjusting device and a horizontal position adjusting device, and FIG. 6 is a perspective view showing a state of a fusion portion by a conventional method. 1,2 …… Optical fiber, 3,3a …… Drawing table, 4,4a …… Optical fiber temporary fixing device, 5,5a …… Vertical position adjusting device, 6,6a …… Horizontal position adjusting device, 7,7a ...... Optical fiber fixing device, 8,8a ...... Movable table, 9 ...... Wire, 10 ...... Pulley, 11 ...... Weight, 12 ...... Air supply pipe, 31,32 ...... Optical fiber, 33 ...... Core, 34 ... Fusion part, 35 ... Fusion extension part, 41, 42 ... Optical fiber, 43, 43a ... Optical fiber temporary fixing device, 44, 44a ... Vertical position adjusting device, 45, 45a ... Horizontal Position adjusting device, 46a, 46b, 46c, 46d …… Optical fiber fixing device, 47, 47a …… Drawing table, 51 …… Knob, 52 …… Fiber position adjusting plate.

Claims (1)

[Claims] 1. An optical coupler manufacturing apparatus for manufacturing an optical fiber coupler by heat-sealing and extending a part of a plurality of optical fibers to each other in a longitudinal direction, and fixing a part of each of the plurality of optical fibers. And a plurality of movable bases that are movable in the longitudinal direction of the respective optical fibers, and a drive mechanism for driving the movable bases so that the tensions applied to the plurality of optical fibers are made substantially equal. Optical fiber coupler manufacturing equipment.