JPS6042716A - Manufacture of optical fiber terminal provided with pseudo spherical lens - Google Patents

Abstract

PURPOSE:To obtain an optical fiber terminal provided with a pseudo spherical lens by means of only working, by cutting the tip part of an optical fiber, executing an electric discharge processing, putting it into a gas when the tip part is deformed to a sphere, and also executing an electric discharge heating. CONSTITUTION:An optical fiber tip part 1 is heated by a DC discharge. As a result, the optical fiber tip part 1 is deformed to a sphere to some extent. This tip becomes a high temperature state of >=1,400 deg.C, therefore, in this case, a gas such as GeCl4 for enlarging its refractive index against a quartz compound fiber is blown to the optical fiber tip 1. As a result, the optical fiber tip comes to operate as a spherical lens. Accordingly, an optical fiber terminal provided with a pseudo spherical lens can be obtained by only working the tip of an optical fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for manufacturing an optical fiber terminal in which a pseudo-spherical lens that has the same effect as a spherical lens is added by simply processing the tip of the optical fiber.

(2) Background of the technology In recent years, various methods have been proposed for processing the tips of optical fibers, and various optical fiber terminals have been used.

For example, techniques for increasing light convergence by attaching a ball lens to the tip of an optical fiber are becoming more active.

(3) Prior art and problems It is generally known that adding a spherical lens to the tip of an optical fiber to increase the coupling rate of incident light is a significant way to improve the light convergence of the optical fiber. .

Conventionally, an optical fiber with a ball lens was made into one terminal by fixing the ball lens and the tip of the optical fiber one by one with high positional accuracy. At this time, it was necessary to prepare an expensive ball lens, and it was necessary to use a ball lens with high positional accuracy and an optical fiber application.

(4) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention aims to provide an optical fiber terminal with a pseudo-spherical lens which functions similarly to an optical fiber terminal with a spherical lens by simply processing the tip of the optical fiber. This is the purpose.

(5) Structure and object of the invention According to the present invention, the tip of an optical fiber is cut perpendicularly to the optical axis using a fiber force/tear, and the tip of the optical fiber is subjected to electrical discharge treatment. However, when the tip of the optical fiber is deformed into a spherical shape, it is placed in an atmosphere of a gas that increases its refractive index, and is further heated by electric discharge to process only the spherical portion into a spherical shape with a high refractive index. This is achieved by providing a method for manufacturing one end of an optical fiber with a pseudo-spherical lens.

(6) Embodiment of the Invention FIG. 1 is an explanatory diagram showing the production sequence of a method for producing one end of an optical fiber with a pseudo-spherical lens according to the present invention.

First, the optical fiber terminal 1 shown in FIG.

Next, as shown in FIG. 1fbl, the tip of the optical fiber is heated by direct current discharge. 2 indicates a discharge arc. As a result, the tip of the optical fiber is deformed into a spherical shape to some extent. Next, as shown in Figure 1 (C1), a GeCl gas is blown and the discharge is continued until it becomes a sphere with a predetermined shape.As a result, only the spherical part can have a high refractive index and can act as a spherical lens. .

FIG. 2 shows the characteristics of an optical fiber terminal with a pseudo-spherical lens manufactured according to the present invention. That is, the expected refractive index distribution is that the refractive index increases in the pseudo-spherical lens 13 at the tip of the optical fiber, and in the other parts of the rod-shaped optical fiber, the refractive index of the core 11 is lower than that of the cladding 12. big.

In this way, the present invention processes the tip of an optical fiber into a spherical shape by electric discharge, and at the same time, when the tip is deformed into this spherical shape,
Since the tip reaches a high temperature of 1,400° C. or higher, a gas such as G8CL+, which increases the refractive index of the silica fiber, is blown onto the tip of the high-temperature optical fiber.

As a result, the optical fiber tip acts as a spherical lens. In the case of GeCl4, this gas is thermally decomposed,
Ge is attached to the fiber tip, which enters the tip by thermal diffusion and changes the refractive index of the spherical section.

In addition, the present invention does not only produce one terminal of an optical core with a pseudo-spherical lens at the same time as the electric discharge machining as in the above-mentioned method, but also fabricates the tip of the optical fiber into a spherical strip by electrical discharge machining, and then fabricates the spherical part. It is also possible to realize a manufacturing method in which the refractive index of the optical fiber is changed, and a manufacturing method in which the refractive index of the tip of the optical fiber is increased and then the fiber is shaped into a sphere by electrical discharge machining.

(7) Effects of the invention As explained in detail above, according to the method for producing an optical fiber terminal with a pseudo-spherical lens of the present invention, there is no need to prepare a separate spherical lens, and there is no need for assembly with high positional accuracy. Therefore, it is possible to produce an optical fiber terminal at low cost and with high mass productivity.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a method for producing one end of an optical fiber with a pseudo-spherical lens according to the present invention, and FIG. 2 is a characteristic distribution diagram of the optical fiber with a pseudo-spherical lens produced according to the present invention. In the drawings, 1 is an optical fiber terminal, 2 is a discharge arc, 3 is G e CI i, 11 is a core, 12 is a cladding, and 13 is a pseudo-spherical lens. (θ) (b) 1 Figure 2 (C)

Claims (1)

[Claims] The tip of the optical fiber is cut perpendicular to the optical axis with a fiber optic knife, and the tip of the optical fiber is then subjected to electrical discharge treatment, so that the tip of the optical fiber is deformed into a spherical shape. When the spherical part is placed in an atmosphere of gas that increases its refractive index, it is further heated by the electric discharge G, and the refractive index of only the spherical part is increased. One terminal fabrication method.