JPH0560933A - Terminal treatment for fusion splicing of optical fiber - Google Patents

Abstract

PURPOSE:To surely and efficiently remove a coating film without damaging an optical fiber and to prevent fiber axis fluctuation and optical fiber contact scratch caused by swelling of an ultraviolet curing resin layer newly formed by chemically removing an ultraviolet curing resin layer. CONSTITUTION:The ultraviolet curing resin layer 1 is dipped and removed in a swelling agent from a terminal of an optical fiber to the ring shaped chamfer 5 and furthermore the bared aluminium layer 2 is removed by dipping into a dissolving solution and the ultraviolet curing resin layer 4 is formed on the exposed optical fiber 3 except the tip fusion splicing part in uniformal film thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal treatment method for fusion splicing of optical fibers, and more particularly to high strength fusion splicing of an optical fiber in which an aluminum layer and an ultraviolet curable resin layer are sequentially coated on the outer circumference of a central optical fiber strand. The present invention relates to a terminal treatment method for optical fiber fusion splicing.

[0002]

2. Description of the Related Art Generally, in order to perform fusion splicing of optical fibers, it is necessary to remove the coating layer of the fusion splicing portion to expose the optical fiber strands. The strength of the fusion splicing part deteriorates to about 1/10 or less of the optical fiber core strength due to the scratches and contact scratches that occur in the coating removal process and the setting process for the fusion splicer, and the adhesion of foreign matter during fusion. To do. 2. Description of the Related Art Conventionally, as shown in FIG. 2, this type of fusion splicing terminal treatment method mechanically removes the ultraviolet curable resin layer 11 and then removes the exposed aluminum layer 12 by an electrolysis method to produce an optical fiber element. The line 3 is exposed to complete the procedure.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned conventional fusion splicing terminal treatment method, the UV curable resin layer is mechanically extracted, so that there is a problem of adhesion between the UV curable resin layer and the aluminum layer and a coating removing tool. There is a risk that not only the aluminum layer but also the optical fiber wire will be damaged depending on the machinability of 1., and it was difficult to remove the ultraviolet curable resin layer efficiently. In addition, since the exposed aluminum layer was removed by an electrolysis method using, for example, a nickel chloride solution after removing the ultraviolet curable resin layer, the electrode gripping portion immersed in the solution was deteriorated by electrolytic corrosion, and the holding property of the clamp and There was also a drawback that the contact resistance changed and the aluminum layer could not be removed. In addition, when the aluminum layer is removed, the liquid penetrates into the UV curable resin layer due to capillary action and the UV curable resin layer swells, so the UV curable resin layer is clamped and melted for the purpose of preventing contact scratches on the optical fiber strand. When set in a connecting / disconnecting machine, the center axis of the optical fiber fluctuates, fiber alignment becomes difficult, the accuracy of fiber connection deteriorates, and there is a drawback that the connection loss increases. In order to avoid the fluctuation due to the swelling, it takes several tens of minutes to 1 hour at room temperature to evaporate the permeated liquid, so that there is a problem that a series of terminal treatments takes a long time.

An object of the present invention is to chemically remove from the end of an optical fiber in which an aluminum layer and an ultraviolet curable resin layer are sequentially coated on the outer circumference of an optical fiber strand to a portion of a predetermined length, and to chuck the optical fiber. An object of the present invention is to provide a terminal treatment method for optical fiber fusion splicing which solves the above problems by forming an ultraviolet curable resin layer on an optical fiber element wire at a grip portion.

[0005]

The terminal treatment method for fusion splicing of an optical fiber according to the present invention is performed in advance from the end of an optical fiber in which an aluminum layer and a first ultraviolet curable resin layer are sequentially coated on the outer periphery of an optical fiber element wire. The first up to the specified length
After removing the ultraviolet curable resin layer by swelling with a swelling agent, the exposed aluminum layer is further removed by immersing in an aluminum solution, and then the exposed end of the optical fiber element wire is removed to remove the optical fiber. A second ultraviolet curable resin layer having a uniform film thickness is formed on the strand.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. FIG. 1 (a) is a perspective view of an optical fiber terminal processed by this embodiment, and FIG. 1 (b) is a longitudinal section of an optical fiber core wire before processing. It is a side view. In this embodiment, an ultraviolet curable resin layer 1 which is a secondary coating
Then, the terminal treatment is completed by including the ultraviolet curable resin layer 4 and the optical fiber element wire 3 which are newly and uniformly covered on the fiber element wire after the fiber element wire is exposed.

The processing method of this embodiment will be described below. The aluminum layer 2 and the ultraviolet curable resin layer 1 are sequentially coated on the outer periphery of the optical fiber element wire 3 and processed from the end of the optical fiber to a place having a preset length with, for example, a cutting tool, and
A ring-shaped notch 5 is formed in the ultraviolet curable resin layer 1 as shown in FIG. After this notch processing, the portion from the end to the ring-shaped notch 5 is dipped in methylene chloride or acetone which has the action of swelling the ultraviolet curable resin layer 1 to swell and remove the ultraviolet curable resin layer 1. Then, the exposed aluminum layer 2 is immersed in a cupric chloride or ferric chloride solution to dissolve the aluminum. Further, chlorine or the like adhering to the exposed optical fiber element wire 3 is removed by, for example, ultrasonic cleaning. After that, the portion of the optical fiber element wire 3 excluding the fused portion is covered with an ultraviolet curable resin 4 made of, for example, a urethane acrylate resin so as to have a uniform film thickness. By the above processing, the optical fiber terminal as shown in FIG. 1A is obtained, the ultraviolet curable resin layer 4 has high hardness, and the optical fiber element wire 3 is not damaged even if it is gripped by the chuck. ..

[0009]

As described above, according to the present invention, since the ultraviolet curable resin layer is chemically removed, it is possible to surely and efficiently perform the light irradiation without being influenced by the adhesion between the coatings and the machinability of the coating removing tool. The coating can be removed without damaging the fiber strand. In addition, since corrosive substances that dissolve metals by simply immersing in a solution are used instead of electrolysis, aluminum can be easily removed, and the conventional electrode gripping part deteriorates due to electrolytic corrosion, and the aluminum layer cannot be removed. Disappear. In addition, the fiber axis fluctuation caused by the swelling of the UV-curable resin layer from the permeation of the solution, which has been a problem in the conventional method, is due to the new UV-curing applied to the exposed optical fiber ancestors excluding the fused portion. This is solved by chucking the uniform film thickness of the resin layer, and the time for evaporating the permeating liquid can be omitted, so that the time for the construction method can be shortened. In addition, the newly applied UV-curable resin layer also has the role of protecting the optical fiber strands, preventing damage to the strands when they are set in the fusion machine and realizing high-strength fusion splicing. The drawbacks of the conventional method can be corrected.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 (a) is a perspective view of an optical fiber terminal processed by this embodiment, and FIG. 1 (b) is a longitudinal sectional view of an optical fiber core wire before processing. Is.

FIG. 2 is a perspective view showing an example of a conventional terminal treatment method.

[Explanation of symbols]

 1,11 UV curable resin layer (secondary coating) 2,12 Aluminum layer (primary coating) 3 Optical fiber element wire 4 UV curable resin layer having a uniform film thickness 5 Ring-shaped notch

Claims (2)

[Claims] 1. A swelling agent for the first ultraviolet curable resin layer from an end of an optical fiber in which an aluminum layer and a first ultraviolet curable resin layer are sequentially coated on an outer circumference of an optical fiber element wire to a position of a predetermined length. After being removed by immersing in the aluminum fiber, the exposed aluminum layer is removed by immersing in an aluminum solution, and then the exposed end fusion portion of the optical fiber element wire is removed to form a uniform film thickness on the optical fiber element wire. An optical fiber fusion splicing terminal treatment method characterized by forming a second ultraviolet curable resin layer having the same. 2. The terminal treatment method for optical fiber fusion splicing according to claim 1, wherein a notch is formed in the portion of the first ultraviolet curable resin layer having the predetermined length.