JPS614006A - Method and mechanism for connecting optical fiber by welding - Google Patents

Abstract

PURPOSE:To obtain a high-strength connection part through stable heating by flowing gas from electrode rods which are stored in insulating pipes opposite each other and making a connection by welding. CONSTITUTION:An optical fiber core 1 having the optical fiber core 1 exposed by removing the coating layer is fixed with a clamp 3, electrode rods 4 stored in the insulating pipes 7 concentrically are arranged opposite each other, and the gas is blown out to a connection point from the gaps between the rods 4 and pipe 7 as shown by arrows to perform discharge heating. Therefore, the necessary amount of the gas is reduced and the high-strength connection part is obtained by the stable discharge heating.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method and mechanism for high-strength fusion splicing of optical fibers using discharge heating.

Fusion splicing using discharge heating has been investigated. Conventionally, a method has been adopted in which gas is supplied from below or above the optical fibers to be connected.

Figure 1 shows an example of a conventional connection method, in which (A) is a top view, (B) is a side view, and (I) is an optical fiber core wire.
(2) is the optical fiber to be connected, (3) is the clamp that fixes the optical fiber core wire, (4) is the electrode support provided oppositely, (5) is the gas supply port, and (6) is the gas station. It is Sokkahar. The optical fiber (2) to be connected is located in the gas station and cover (6), and is connected from the gas supply port (5) to -
1- The optical fiber (2) was fused and connected by electrical discharge heating using the electrode rod (4) while supplying helium gas or other inert gas into the gas stock cover (6).

However, in such a method, depending on the gas flow rate, the discharge may be disturbed in the outflow direction of the waste, and the gas supply has been stopped immediately before the discharge. Therefore, there is a risk that the gas may diffuse depending on the time after the stop, and in order to prevent this, the entire gas stock cover is filled with gas, whereas normally there should be gas around the connection part. This required a large amount of gas.

(Disclosure of the Invention) The present invention provides a high-strength connection part (□61
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．． The first feature of the 46° is the connection method that performs fusion splicing while flowing gas along the opposing electrode rods, and the second
The feature of this is that the opposing electrode rods are housed in an insulated pipe, and the connection mechanism uses the gap between the electrode rod and the insulated pipe as a gas flow path.

The present invention will be described in detail below with reference to the drawings. FIG. 2 shows a first embodiment of the present invention, in which (a) is a two-sided view and (b) is a side view. FIG. 3 is a two-sided view showing another embodiment of the present invention.

In Figure 2, the coating layer near the end of the optical fiber (1) is removed to expose the optical fiber (2) to be connected, and the optical fiber (2) is made to avoid contact with other objects. Then, the optical fiber (1) is fixed with a clamp (3). The opposing electrode rods (4) are each housed almost concentrically in an insulated pipe (7) made of quartz glass or the like, and the gap formed between the electrode 11 (4) and the insulated pipe (7) serves as a gas flow path. The gas is blown out in the direction of the arrow. The flow rate, pressure, etc. of the gas blown out from the gas flow path are controlled to be equal, and adjusted so as not to disturb the discharge.

FIG. 3 shows another embodiment of the present invention, in which the electrode rod (4
The insulating pipe (8) that accommodates the optical fiber (2) extends in the right angle direction and almost concentrically covers the optical fiber (2) to be connected. At this time, from the viewpoint of workability such as attaching and taking out the optical fiber (2), the insulating pipe (8) should have a slit (8^) as shown in Fig. 4 (A) or a pipe as shown in Fig. 4 (A). B)
You may choose to use a two-split pipe (sA) (sc) as shown in the figure below.

Alternatively, as shown in FIG. 5, the insulating pipe (8) may be fused and spliced without being heated from the outside with a heater (9) or an oxyhydrogen bath (not shown). Furthermore, instead of heating from the outside, as shown in FIG. 6, a pipe (10) whose heating resistor is insulated and protected with ceramic or the like may be used to utilize the heat generated from the pipe itself.

(Example) As Experiment 1, the coating layer of the optical fiber cored wire terminal was removed with hot sulfuric acid to expose the optical fiber to be connected, and the optical fiber was connected with care to prevent the optical fiber from coming into contact with other objects. The core wire was fixed with a clamp. Next, the electrode rod and the optical fiber were housed in the slinted quartz pipe shown in FIG. 4(a). For this slit, after storing the optical fiber, we conducted an experiment by cutting the fiber in half. First, before starting the discharge, we supplied helium gas into the quartz pipe along the electrode rod, aligned the axis in this state, and conducted the discharge for 2 seconds. The optical fibers were fused and spliced, and the gas supply was also stopped when the discharge stopped.

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! Experiment 2 was conducted in the same manner as Experiment 1, and then gas was supplied for 5 seconds even after the discharge was stopped. Experiment 3 was carried out by heating the quartz pipe with a heater installed at the bottom as shown in Fig. 5, and raising the internal temperature of the gas flow pipe to 100"C or higher. Also, in Experiment 4, it was carried out at the top. Immediately after the oxyhydrogen burner reaches a predetermined temperature, the gas inside the pipe is used to control the temperature by increasing the flow rate of the gas inside the pipe, and after the burner heating is stopped, the gas inside the pipe is used to slowly cool the pipe and the optical fiber connection. The flow rate was controlled to

The results of each of the above experiments are shown in the table below. In each n-30 test, the average strength of the fusion of the joint using the conventional method using helium gas was 3.0 kg, and the maximum strength was 4.3 kg.
On the other hand, it can be seen that in Experiments 1 to 4, there was a remarkable improvement. The respective Weibull floats are shown in Figure 7.

Although quartz pipes with the same diameter were used in the above experiment, ceramic or the like may be used as the abrasive material, and the diameter of the pipes is not necessarily the same, but a tapered pipe may be used. Further, in the experiment, helium gas was used to stabilize the discharge, but other inert gases may be used without any restriction.

4 (Effects of the Invention) The connection method of the present invention provides the following effects.

(1) The electrode rod is housed in an insulated pipe, and the gap is used as a gas flow path to perform discharge heating while flowing gas concentrated at the connection point, unlike conventional gas stock covers. There is no need to fill the tank, and the amount of gas required can be reduced to less than 171O compared to the conventional method.

(2) By continuing to stably flow the gas along the electrode rods facing each other, it became possible to perform stable discharge heating.

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(4) By continuing to flow the gas even after the discharge was stopped, it was possible to prevent impurities from adhering to the surface of the optical fiber.

(5) By preheating the insulated pipe, the electrode rod was also heated, further stabilizing the initial discharge.

(6) By heating the insulated pipe, rapid cooling of the optical fiber can be prevented even after the discharge has stopped, and the connection part can be cooled slowly.

[Brief explanation of drawings]

Figure 1 is an example of the conventional connection method.
b) is a side view, and Fig. 2 is an embodiment of the connection method of the present invention (
A) is a two-sided view, (b) is a side view, FIG. 3 is a two-sided view of another embodiment of the connection method of the present invention, and FIG.
Insulating pipe with slits (a) used in the examples
Figure 5 is a two-sided view of another embodiment of the present invention, Figure 6 is an example of an insulated pipe having a heating element inside, FIG. 7 shows the Weibull flot of the experimental results. Scraping rod, 7, 8... Insulated pipe, 9... Heater.

Claims (7)

[Claims] (1) A method for fusion splicing optical fibers using discharge heating, which is characterized in that the fusion splice is performed while flowing gas along opposing electrode rods. (2) The first aspect of the present invention is characterized in that the fusion splicing is performed while the gas is further caused to flow along the optical fiber.
Optical fiber fusion splicing method described in section. (3) The optical fiber fusion splicing method according to claim 1 or 2, wherein the gas continues to flow for a certain period of time even after the discharge for fusion splicing is stopped. (4) The optical fiber fusion splicing method according to claim 1 or 2, characterized in that the gas flow path is heated. (5) An optical fiber fusion splicing mechanism characterized in that opposing electrode rods are housed within an insulated pipe, and a gap between the electrode rod and the insulated pipe is used as a gas flow path. (6) The optical fiber fusion splicing mechanism according to claim 5, wherein the insulating pipe is extended and provided to cover the optical fiber. (7) The optical fiber fusion splicing mechanism according to claim 5 or 6, wherein the insulating pipe has a heating element inside.