JPS58120215A - Method for connecting optical fiber - Google Patents

Abstract

PURPOSE:To obtain a connecting part having the large strength of the connecting part and the less optical loss, by heat-fusing optical fibers in halogenated gaseous methane or gaseous mixture in which the halogenated gaseous methane is incorporated in case of heatfusing the optical fibers. CONSTITUTION:Optical fibers are heat-fused in gas such as CCl4, CF4, Cl2F2 or Cl3F3, in gaseous Ar in which above-mentioned is incorporated. After the optical fibers, the coating of which is removed is set at a discharge-fusion connecting device and the optical axis is aligned, the vicinity of an electrode part for discharge including a connecting part is shielded by a box made of acrylic resin and the gas in which gaseous Ar etc. is subjected to a bubbling in halogented methane gas or halogenated methane liquid, is made to flow the box to substitute with the atmosphere, and then fused by discharge. By this way, the connection strength which is several times stronger than that of a fusion in the atmosphere is obtained and the connection loss is the same as that of the connection in the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for connecting source fibers by heat fusion.

Conventionally, for example, the method for connecting optical fibers is to adjust the ends of a pair of optical fibers to be connected to each other so that they are coaxial with each other using an alignment mechanism, and then to sandwich the ends of the fibers and connect them relative to each other. A method of connecting optical fibers by so-called discharge fusion has been proposed, in which the tips of the optical fibers to be connected are fused by pressure welding and heat melting using a pair of discharge electrodes arranged facing each other.

This method of connecting optical fibers by electrical discharge fusion has the advantage of being simple and having low loss at the spliced portion, but the strength of the spliced portion is reduced to about 177 times the strength of the original optical fiber. It had a serious drawback.

In order to eliminate these drawbacks of the conventional technology, the inventors of the present invention have conducted various studies and have come to the knowledge that there is a correlation between the type of atmospheric gas during heat fusion and the strength of the connection. Ta.

The present invention was made based on such knowledge and as a result of studying the atmospheric gas of the fibers in order to prevent the strength deterioration of the fusion spliced portion of the original fiber. The present invention provides a method for connecting source fibers characterized by fusion splicing.

Next, examples of the present invention will be described. The outside diameter 12 was carefully removed to avoid damaging the fiber strands.
Set the 5μm quartz 7-eye in the discharge fusion splicer,
After the alignment was adjusted, the vicinity of the discharge electrode section including the tips of the pair of optical fibers to be connected was shielded with an acrylic box. After that, carbon tetrachloride CCT4 liquid placed in a glass container was made by bubbling argon gas Ar (CCl4 +Ar
) By flowing the mixed gas into the shielding box at a flow rate of 20 cc/min for 5 minutes, gas replacement with the atmosphere is performed, and fusion splicing is performed under the conditions of a discharge voltage of about 70 V and a heating time of 5 to 20 seconds. Ta. The average splice strength of the original fibers spliced in this way was 3 kg, which was much higher than the average splice strength of the optical fibers spliced in the atmosphere, which was 0.9 kg.

Next, when a similar experiment was conducted using a (CCt4+C02) mixed gas, an average connection strength of 3.6 kg per stroke was obtained. Furthermore, the splice loss of optical fibers spliced in these mixed gases was no different from that when spliced in the atmosphere.

Other carbon tetrafluoride CF4 + chlorine fluoromethane C
t2F2 *) Chlorfluoromethane CC43
Almost the same effect could be obtained even when a mixture of halogenated methane gas such as F and argon gas Ar or carbon dioxide CO2 was used as the mixed gas.

As explained above, the optical fino connection method of the present invention has the effect of being able to perform fusion splicing with much higher strength than conventional connection methods.

Patent applicant: International Telegraph and Telephone Corporation Physician Manabu Daitsuka 1 other person

Claims (3)

[Claims] (1) A method for connecting optical fibers in which optical fibers to be connected to each other are thermally fused together, characterized in that the optical fibers are thermally fused in halogenated methane gas or a mixed gas containing halogenated methane gas. . (2) The halogenated methane gas is CC4, CF4
, CL2F2 or CCl2F, the method for connecting source fibers according to claim 1. (3) The method for connecting source fibers according to claim 1, wherein the mixed gas is (CCt4+C02) gas.