JPH03211509A - Apparatus for producing optical fiber coupler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an apparatus for manufacturing an optical fiber coupler by fusing and drawing a plurality of optical fibers.

(Prior art) The coating of the optical fiber is removed and the glass portion of the optical fiber is removed.
The optical fiber alignment unit is constructed by storing the optical fibers in a groove of a support base having a storage groove, providing a holding part at one end and a pressure gauge at the other end, and applying a holding force of 0 to 10 g to the fibers. Already suggested.

FIG. 4 is for explaining the prior art, and (A
) The figure is for explaining how to align optical fibers during fusion splicing. In the figure, 41 is a coating part of the optical fiber, 42 is a glass part of the optical fiber, 43 is a gas burner, 44 is a flame, 45 is a grooved support base, 46 is a holding part for the optical fiber glass part, 47 is an upper support base, 48 is a pressure gauge. At the time of fusion, as shown in the cross section in FIG. 3(B), the glass portion 42 of the optical fiber is supported in the groove of the grooved support 45 and is aligned by being pressed by the presser portion 46 of the optical fiber glass portion.

In the configuration of such a conventional device, when a pressing force is applied to align the two optical fibers during fusion to bring the fused parts into contact, the fused part is removed from the covering part 41 as shown in Figure (C). Bending is applied towards the end of the

Even if this bending is not the same for multiple optical fibers, no problem will occur during fusion (increase in insertion loss due to light leakage due to fusion), but during stretching, as shown in Figure (D). As shown in FIG.
The tension TaO applied to the optical fiber 2a becomes larger than the tension Tb applied to the optical fiber 42b, which has a large amount of slack, and the balance of the tension applied to both optical fibers (the mutually fused optical fibers) is lost, causing the bending and fusion splicing. There is a difference between the fused portion and the unfused portion, resulting in a distorted tapered shape during stretching, resulting in light leakage from that portion, resulting in an increase in insertion loss.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned problems, and when aligning optical fibers during fusion, it balances the force applied to each optical fiber and prevents bending. It is an object of the present invention to provide an optical fiber coupler manufacturing apparatus that can manufacture optical fiber couplers with less variation in excess loss by using optical fiber alignment parts that can be made equal.

(Means for Solving the Problems) The present invention provides an apparatus for manufacturing an optical fiber coupler in which a part of the longitudinal coating of a plurality of optical fibers is removed and a plurality of optical fibers are fused and stretched. It is characterized by having a gripping part that can grip the coated part of the optical fiber from the lateral direction, and a pressing part that holds the part from which the coating has been removed with a constant load from the vertical direction and aligns the optical fiber.

(Function) The present invention grips the coated portions of a plurality of lined-up optical fibers from the lateral direction, and presses the portion from which the coating has been removed with a constant load from the vertical direction. It can be bent into the same shape and made to touch.

(Example) FIG. 1 is a perspective view for explaining an example of the present invention. In the figure, 1 is a coating part of the optical fiber, 2 is a glass part of the optical fiber, 3 is a gas burner, 4 is a flame, 5 is a clamper for the optical fiber coating part, 6 is a drawing stage, and 7 is a presser part for the optical fiber glass part. , 8 is a weight, 9 is a thread, 10 is a linear bearing, and 11 is a guide roller.

The clamper 5 is placed on a stretching stage 6 for stretching the optical fibers in the axial direction, and clamps the covering portions 2 of the two aligned optical fibers from the lateral direction. The holding portion 7 of the optical fiber glass portion presses the longitudinally uncoated portion of the optical fiber with a constant tension from the vertical direction, which is a direction perpendicular to the clamper 5, during fusion. Figure 2 (A)
As shown in the schematic configuration, the pressing force is applied from a weight 8 to apply a constant load. That is, the linear bearing 10 applies force by the weight 8 to the thread 9 in two directions and can move in the axial direction of the optical fiber via the guide roller 11.
to balance the load.

Explain about load balance. For example, in Figure 2 (B
), it is assumed that one of the optical fibers 2a is bent by one of the clampers 7a.

Then, due to the rigidity of the optical fiber 2a, the clamper 7a
stops, but its displacement increases, and as shown in Figure (D), the weight 8 swings to the left from the dotted line position, which is the balance position, and moves to the solid line position. Due to the movement of the weight, the tension of the thread 10b against the stage 10b becomes greater than the tension Ta of the thread on the stage 10a of the linear bearing, and the force applied to the clamper 7b becomes larger, and as shown in FIG. The fibers are subjected to uniform forces and are bent into the same shape, allowing them to be brought into contact with the same force.

Therefore, as shown in Figure (E), not only the case where the outer diameter of the coating of the optical fiber is the same as shown by the solid line, but also the case where the outer diameter of the coating of the optical fiber varies as shown by the dotted line. Also, the load applied to both optical fibers is constant, and the force applied to both fibers trying to be fused is the same,
It becomes possible to align the fibers.

FIG. 3 shows the structure of the clamper used in the experiment. (A) The diagram shows clampers 7 each having two arms.
A and 7b are plan views showing the outline of the clamp part, (B)
As shown in the perspective view in the figure, one side has a groove 7C for holding the optical fiber and V-shaped guides 7d on both sides for guiding the optical fiber into the groove 7C. The other one has a convex portion 7e for holding the optical fiber toward the groove 7C between the V-shaped guides 7d. The distance between the two arms of the clamper is 15 mm, and the portion holding the optical fiber is 5 mm.

The angle of the V-shaped guide for guiding the optical fiber into the groove is
The groove 7C has a groove width of 135 μm and a depth of 2.
00 μm.

The prototype has a cladding diameter of 125μm±1.5μm.

Using an optical fiber that is a normal 1.3 μm band single mode optical fiber with MFD = 9.5 ± 1 μm and a cutoff wavelength of 1.2 μm, finished with an outer diameter of 0.25 mm using ultraviolet curable resin, We prototyped an optical fiber coupler with the goal of achieving a branching ratio within 50% ± 3% at a wavelength of 1.3 μm.
We decided to evaluate excess losses. The removal length of the coating is 3
0 mm, and heat fusion was performed using an acetylene and oxygen burner. For fusion, the fiber temperature is 1 with a radiation thermometer.
After heating to 400°C for 5 minutes, the stretching tension was 3.
g was added to perform stretching. A power meter was connected to an LD light source with a wavelength of 1.3 μm at both ends of the optical fiber to monitor the branching state during stretching, and when the branching state reached the desired 50%, the burner was moved away from the fiber to stop the stretching.

Tests were conducted on 30 kaburas prototyped using the conventional technology and 30 kaburas prototyped using the apparatus of the present invention. The average value of excess loss according to the conventional technology is 0.29 dB, and the maximum value is 0.29 dB.
6 dB, whereas the average value of excess loss according to the present invention was 0.18 dB, and the maximum was 0.46 dB, which was good.

(Effects of the Invention) As is clear from the above description, according to the present invention, by balancing the force applied to the fibers when aligning the optical fibers during fusion during the production of optical fiber couplers, the tension during stretching can be reduced. can be applied to the fiber in the same manner, which has the effect of reducing variations in excess loss of the optical fiber coupler.

[Brief explanation of drawings]

FIG. 1 is a perspective view for explaining one embodiment of the present invention;
FIG. 2 is an explanatory diagram of the operation in the clamper section, FIG. 3 is an explanatory diagram of an embodiment of the clamper, and FIG. 4 is an explanatory diagram of a conventional clamper. DESCRIPTION OF SYMBOLS 1... Coating part of optical fiber, 2... Glass part of optical fiber, 3... Gas burner, 4... Flame, 5...
Optical fiber coating clamper, 6... stretching stage,
7... Holding part of the optical fiber glass part, 8... Weight,
9... Thread, 10... Linear bearing.

Claims (1)

[Claims] Remove part of the longitudinal coating of multiple optical fibers,
A manufacturing device for an optical fiber coupler formed by fusion-stretching has a gripping part that can grip the coated part of a plurality of lined up optical fibers from the horizontal direction, and a part from which the coating has been removed by applying a constant load from the vertical direction. 1. A manufacturing device for an optical fiber coupler, comprising a presser foot and a press-contact portion for aligning optical fibers.