JPS59115A - Method for connecting optical fiber by fusing - Google Patents

Abstract

PURPOSE:To prevent occurrence of minute scars in the course of connecting optical fibers by fusion and improve the strength of the connected part, by performing the heating and fusion of optical fibers under an inactivated atmosphere. CONSTITUTION:A chamber 10 to be used for creating an inactivated atmosphere is a square box type one made of, for example, transparent quartz, and composed of a main body 12 and top part 14 coupled with the main body by means of a hinge 16. Two optical fibers 20 to be connected with each other are inserted into the chamber 10 through holes 18 installed at the boundary of the main body 12 and top part 14. The optical fibers 20 are fused and connected with each other by arc discharge of tungsten electrodes 30 while an inactive gas is made to flow by blowing in the chamber 10. After the optical fibers 20 are connected by fusion, the top part 14 is opened and the connected optical fiber 20 is taken out. In this case, the strength of the connected part by fusion can be improved as shown by the graph where the Weibull distribution A when the fusion is made by the arc discharge under an Ar gas atmosphere and that B when fusion is made in air are shown.

Description

DETAILED DESCRIPTION OF THE INVENTION Heat fusing of optical fibers is usually performed in air. Therefore, active substances present in the air (02, +
+2, OH, etc.) causes minute scratches on the surface of the optical fiber during fusion, and as a result, the strength of the optical fiber at the fused portion deteriorates to about 115 to 1/10 of that before fusion.

The present invention is based on the new recognition of the phenomenon described in -1-, and provides an optical fiber fusion splicing method that can suppress the occurrence of minute scratches that occur during fusion splicing and achieve higher strength than conventional methods. The purpose is to provide the following.

The present invention is characterized in that optical fibers are thermally fused not in air but in inert atmosphere.

Inert atmosphere is used to mean in the presence of an inert gas or in a vacuum.

Note that the inert gas may include N2, CO2, etc., but since these are not inert at the fusion temperature of the optical fiber, in this case, He, Ne.

Only rare gases such as Ar are used.

In the embodiment [Figs. 1 and 2], 10 is a chamber for creating an inert atmosphere, and is a rectangular box-shaped chamber made of transparent quartz, for example. It consists of a main body 12 and a lid 14, and the sides are hinged 16 to each other so that the optical fiber 20 after being fused can be taken out.

The optical fiber 20 is inserted into the interior through a hole 18 provided at the boundary between the main body 12 and the lid 14. optical fiber 2
There is a slight gap around 0, allowing gas to blow out.

30 is a tungsten electrode.

Blow an inert gas 40 into the chamber 10, and
Arc discharge is performed using the tungsten electrode filter 0 to fuse the optical fiber 20.

After fusion, open the lid 14 and connect the optical fiber 2 as described above.
Extract 0.

LJL? Figure 2 shows a case where an electric heater 62 made of nichrome wire, carbon, etc. is used instead of the tungsten electrode filter 0, and the rest is the same as that shown in -.

Figure 1 shows a case where a hot beam filter 4 such as a 002 laser is used. 19 is an airtight window provided in the chamber 10.

In both cases, instead of feeding the inert gas 40, the inside of the chamber 10 may be evacuated and the optical fibers 20 may be fused. However, in that case, the space between the optical fiber 20 and the chamber 10 is hermetically sealed.

Effects of the Invention (1) When A in 1 Fig.
It is clearly seen that the strength of the fusion spliced portion is improved by the present invention based on the Weibull distribution in the case of fusion splicing in air.

(2) Since heat fusion is performed within the chamber, it can also be used in a dangerous situation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Figs. 2 and 2 are sectional views taken along line nn, Fig. 3 and Fig. FIG. 3 is a Weibull distribution diagram of the strength of optical fibers connected by the invention and the conventional method. 10: Chamber 20: Optical fiber 30° 7gusten electrode 62: Electric heater 34 = Heat ray beam 40: Inert gas Patent applicant: Nippon Telegraph and Telephone Public Corporation Fujikura Electric Wire Co., Ltd. Agent Keiji Kokuji

Claims (1)

[Claims] A method for fusion splicing optical fibers, which comprises heating and fusion splicing optical fibers in an inert atmosphere.