JPH01128012A - Production of optical fiber coupler - Google Patents

Abstract

PURPOSE:To prevent combustion of a covering by heating by twisting the optical fibers of the part where the covering is removed by rotating grippers consisting of ceramics materials, then by heating the twisted part to melt, stretch and fix said part, covering the twisted part with a cover while the grippers are held fixed thereto and fixing the part between the grippers. CONSTITUTION:The covered optical fibers 4, 4 are passed through the through- holes of the two grippers 1, 1 and the covering between the grippers held at a prescribed spacing is removed. The covering of the optical fibers is fixed on the same plane as the plane of the end part of the gripping parts or in the position slightly inner than the same. The gripping means are then loosened to rotate the grippers 1, 1 and to twist the optical fibers consisting of the clads and cores in the part where the covering is removed by a desired number of times. The optical fibers of the twisted part are stretched and fixed by moving one of the gripping means in the straight direction shown by an arrow while the optical fibers are kept heated and melted. The cover 13 is wound to the large-diameter parts of the two grippers in the state of fixing the grippers. The melting of the clad part is thereby prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of manufacturing an optical fiber coupler used as one of optical transmission means.

<Prior Art> FIGS. 6 and 7 are diagrams schematically showing the manufacturing process of a conventional optical fiber coupler. FIG. 6 shows that the coating of two optical fibers 4, 4 at a predetermined location (range indicated by L) is removed, the exposed cladding portions 5.5 are twisted together, and the twisted portion is heated with a micro gas torch 6. The optical fiber is heated and melted, one end of the optical fiber is stretched and fixed while slightly moving in the straight direction shown by the arrow, the joined part is housed in a cylindrical protective pipe 12, and both ends of the pipe are bonded with, for example, epoxy adhesive. It was fixed with Agent 10.

<Problems to be Solved by the Invention> In the above-mentioned conventional optical fiber coupler manufacturing method, the coating only needs to be removed by the length of Lo, which is the bonding part, but if the removed part is too small, it will be heated with a micro gas torch. In some cases, the cladding burns and the cladding and core parts, which should not be melted, may melt. Therefore, there is a tendency to remove more of the coating than necessary, resulting in problems such as a decrease in Ijl mechanical strength and an increase in optical loss.

In addition, the optical branching ratio and optical loss change slightly depending on the degree of twist in the molten part, so it is necessary to adjust the degree of twist. The problem was that it was difficult to adjust the condition.

Furthermore, in order to improve the mechanical strength of the joint, a protective vibrator 12 is covered and both ends are fixed with adhesive.
When transporting the rear pipe to the joint, the joint may be damaged or the optical axis may be misaligned due to carelessness, resulting in a problem in that the optical branching ratio changes and optical loss increases.

The present invention has been made in view of the problems of the prior art described above, and uses a gripping tool that can stably fix optical fibers and can adjust the degree of twist, thereby preventing breakage and optical loss. It is an object of the present invention to provide a method of manufacturing an optical fiber coupler with a small number of steps.

Means to solve problems〉 The structure of the present invention for solving the above problems is as follows.

Two gripping tools made of ceramic material in which a plurality of through holes with a diameter slightly larger than the outer diameter of the coating of one optical fiber are formed near the center, and the coating in the middle of the optical fiber is held at a predetermined length. The optical fibers pass through each of the through holes of the plurality of removed optical fibers and the gripping tool, and each of the gripping tools is placed on the coating at both ends from which the coating has been removed, and the gripping tools are held. It consists of a gripping means that grips at predetermined intervals, the gripping tool is rotated to twist the optical fibers in the portions from which the coating has been removed, the twisted portions are heated and melted to stretch and harden, and the gripping tools Covering the space between the gripping tools including the gripping tool with the tool fixed,
It is characterized in that the gripping tools are fixed.

<Example> FIG. 1 is a front view (a) and a side view (b) of a gripping tool 1 used in the present invention, and FIGS. 2 to 5 schematically show the manufacturing process of an optical fiber coupler. In FIG. 1, a 9-grip 1 is made of ceramic material and has two through holes 2.2 approximately in the center of a cylinder having stepped portions of different diameters. This through hole is machined to be slightly larger than the outer diameter of the optical fiber coating (processed using a core during ceramic firing).9For example, in the case of a single mode optical fiber, Q
, 2 mm, and in the case of a multimode optical fiber, it is about 0°4 mm. In addition, the dimensions of this gripping tool are, for example, the large diameter part of 3 m.
m (thickness a; 3mm), small diameter part 2゜5mm (thickness b:
3mm).

Figure 2 shows the installation state before melt processing, and the coated optical fiber 4.4 is attached to two grippers 1,
The coating between the gripping tools passed through the through-hole No. 1 and held at a predetermined interval (a value obtained by adding α to the dimension shown in Figure 6 Lo) is removed, and the coating portion of the optical fiber is connected to the end of the gripping portion. Fixed in the same plane or slightly inward. The small diameter parts of these two gripping tools can be moved in a straight line! (not shown) gripping means (for example collet chuck etc.) 3
It can be rotated by loosening the gripping means 9. By arranging ceramic grippers at both ends of one section in this way.

Since the heat effect does not reach the covered portion, the range of removal of the covering can be made shorter than in the past.

Figure 3 shows how to loosen the gripping means and rotate the gripping tools 1, 1.
I! V! This figure shows the state in which the optical fiber and fiber made up of the cladding and core from which J has been removed have been twisted a desired number of times.

Figure 4 shows the micro gas torch shown in Figure 6 used to heat and melt the twisted portion of the optical fiber while moving one of the gripping means in the straight line direction shown by the arrow to stretch and fix the two gripping tools. FIG. 5 is a completed view showing a state in which the cover 13 is wrapped around the large diameter portions of the two gripping tools in a fixed state. In addition, power.

As the bar 13, a plastic film or thin metal plate is used once or once? ! Wrap it a few times to make it stick. As a cover method, slots may be made in the longitudinal direction of a cylinder formed from a thin plate, and the elasticity of the thin plate may be used to cover the optical fiber and fix it with adhesive, etc. The key is to expose the fused and fixed part to light from the outside. It is only necessary to provide protection so that the metal does not enter, the cover does not come into contact with the joint, and the mechanical force does not come loose.

Note that in this embodiment, the number of optical fibers is two, but the number of optical fibers may be two or more. Further, the dimensions and shape of the gripping tool are not limited to those in this embodiment, and are arbitrary, as long as the plurality of optical fibers can be twisted evenly while being passed through the through holes of the gripping tool.

<Effects of the Invention> As described above in detail with the embodiments, according to the method for manufacturing an optical fiber coupler of the present invention.

(1) Ceramic gripping tools are placed on the coatings at both ends of the optical fiber from which the coating has been removed and heated, which prevents the coating from burning due to heating and prevents the cladding from melting. I can do it.

Further, since the coating is not removed more than necessary, it is possible to reduce the decrease in mechanical strength of the optical fiber and the loss of light.

(2) Since both ends from which the coating has been removed can be fixed with the grips and twisted, the number of twists can be controlled to be as high as V# degrees. Therefore, control and reproducibility of the optical branching ratio can be improved.

(3) Since the cover is attached with the gripping tool fixed, no force is applied to the joints and there is no chance of damage.

[Brief explanation of the drawing]

FIG. 1 shows a plan view (a) and a side view (b) of a gripping tool used in the present invention, and FIGS. 2 to 5 show a light 7 of the present invention. A diagram showing a schematic manufacturing process of Ibakapura. FIGS. 6 and 7 are diagrams schematically showing the manufacturing process of a conventional optical fiber coupler. 1... Gripping tool, 2... Through hole, 3... Gripping means,
4... Optical fiber, 5... Clad part, 13...
cover. Figure 1 Figure S Figure 6 Figure 7

Claims (1)

[Claims] Two gripping tools made of ceramic material in which a plurality of through holes with a diameter slightly larger than the outer diameter of the coating of one optical fiber are formed near the center, and the coating in the middle of the optical fiber is held at a predetermined length. The plurality of removed optical fibers, the optical fibers passing through each of the through holes of the gripping tool, and each of the gripping tools being placed on the coating at both ends from which the coating was removed to hold the gripping tools in a predetermined position. The gripping tool is rotated to twist the optical fibers of the portions from which the coating has been removed, and the twisted portions are heated and melted to stretch and fix, and the gripping tool is A method for manufacturing an optical fiber coupler, characterized in that the gripping tools including the gripping tool are covered with a cover in a fixed state, and the gripping tools are fixed.