JPH01147505A - Curved surface rupture method for optical fiber - Google Patents

Abstract

PURPOSE:To obtain a convex curved surface in a short period of time by forming a part larger in diameter in a fiber to the end part of an optical fiber and cutting the large-diameter part. CONSTITUTION:The end part of the optical fiber 11 is formed by heating and loading to the part 12 larger in diameter than the fiber 11. The large-diameter part 12 and the optical fiber 11 are respectively held and are cut by exerting tension between the same. The cutting is executed at the boundary between the fiber 11 and the large-diameter part 12 and the cut face of the fiber of this time is the convex curved surface 14. The max. stress face at the cutting start point is inclined theta with the face perpendicular to the axis by the effect of the part 12 formed to the diameter larger than the diameter of the fiber 11 and, therefore, the initial crank progresses at the angle theta. The theta approaches zero on progression of the rapture process and is decreased nearly zero in the second half of the rupture process. The rupture is finally completed at theta=0 and, therefore, the convex spherical face 14 is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for breaking a curved surface of an optical fiber, in which a glass optical fiber or a plastic optical fiber is broken, and the broken surface is made into a convex curved surface.

"Prior art" In order to reduce the connection loss of optical fibers, the tips of the optical fibers are polished into spherical shapes as shown in Figure 4, and the spherical end faces of the optical fibers are butted together as shown in Figure 5. A method is used to eliminate the air layer and create a connection with low reflection loss.

Therefore, a technique is required to make the end face of the optical fiber into a convexly curved state. Conventionally, the end of an optical fiber has been polished into a spherical shape using a spherical polishing device. The polishing process takes time and has been an obstacle to reducing the cost of optical fiber connections.

"Means for Solving the Problem" According to the present invention, the end portion of the optical fiber is formed into a shape thicker than the core wire by heating and load, and the formed thick portion and the core wire of the optical fiber are connected. Hold each piece, apply tension between them, and cut at the boundary position of the thick portion to obtain a fractured surface with a convex curved surface.

``Example'' The end of the optical fiber shown in FIG. 1A is formed into a thicker portion 12 than the core wire 11 by heating and applying a load.

The formed thick portion 12 and the coated optical fiber 11 are each held, and tension is applied between them to cut them. In this case, a scar may be made along the periphery at the cutting position, that is, at the boundary 13 between the core wire 11 and the thick portion 12. This cutting is performed at the boundary 13 between the core wire 11 and the thick portion 12, as shown in FIG. 1C. At this time, the cut surface on the core wire 11 side becomes a convex curved surface 14.

Due to the action of the portion 12 that is thicker than the diameter of the core wire 11, the maximum stress surface at the cutting start point has an inclination θ with respect to the plane perpendicular to the axis as shown in Figure 2A, so the initial crack is θ.
Proceed at an angle. As the rupture process progresses, θ approaches zero, and in the latter half of the rupture process, θ
becomes almost zero, and the rupture process is finally completed at θ=0 (Fig. 2C). Therefore, a convex curved surface 14 is obtained on the core wire 11.

The cutting starting point may be scratched with a sharp knife, or an initial crack may be generated by stress concentration without scratching.

The thick portion 12 may have the shape shown in FIG.

"Effects of the Invention" As described above, according to the present invention, at the end of the optical fiber,
The end face of the optical fiber can be made into a convex curved surface by a very simple operation of forming a part with a diameter thicker than the core wire and cutting that thicker part, which is different from the case of forming a convex curved surface by conventional polishing. A convex curved surface can be obtained in a relatively short time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the process of the optical fiber curved surface breaking method according to the present invention, FIG. 2 is a diagram showing the progress of the fracture, FIG. 3 is a diagram showing other shapes of the thick portion 12, and FIG. 4 is a spherical surface. FIG. 5 is a diagram showing a polished optical fiber, and FIG. 5 is a diagram showing a state in which the spherically polished end faces are butted together. Patent applicant Japan Aviation Electronics Industry, Ltd. Representative
Person Takuo Kusano 1 Figure Fai Bao 2 Figure 3 Figure 4 Figure 25 Figure

Claims (1)

[Claims] (1) Form the end of the optical fiber into a shape thicker than the core by heating and applying a load, hold the formed thick part and the core of the optical fiber, and apply tension between them, A curved surface breaking method for optical fibers in which a curved surface is obtained by cutting at the boundary position of the thick portion formed above.