JPH0527122A - Method and device for cutting optical fiber - Google Patents

Abstract

PURPOSE:To eliminate such problems that the fiber is not ruptured even when residual compressive stress is present on the fiber surface and that a complete mirror surface shape is not formed even after rupture like a Ti-doped fiber. CONSTITUTION:When the optical fiber 14 is cut, a fine flaw is made in the surface and then tensile stress is applied to the part to rupture the optical fiber. The residual compressive stress of the optical fiber 14 is removed by a heat treatment before a process wherein the flaw is made. Further, a couple of electrodes 30 which faces each other across the optical fiber 14 are added to the optical fiber cutting device equipped with a cutting edge 22 which gives the fine flaw to the optical fiber 14 and a pressing member 24 which bends and breaks the optical fiber to enable the heat treatment. The electrodes move in a (y) direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cutting an optical fiber.

[0002]

[Prior art]

[About the cutting device] First, regarding the conventional cutting device,
Briefly explained. 5A and 5B schematically show a conventional device. FIG. 5A is a plan view, FIG. 5B is a side view, and a C cross section is shown in FIG. 5C. For convenience of explanation, the directions of x, y, and z are defined as shown by arrows. Reference numeral 10 is the entire optical fiber core wire, 12 is the coated portion thereof, and 14 is the optical fiber. 1
6 is a cover clamp, 18 and 20 are fiber clamps,
A blade 22 has a high hardness and a sharp cutting edge, is located between the fiber clamps 18 and 20, and is movable in the x direction. A pressing member 24 is located between the fiber clamps 18 and 20 and is movable in the y direction, for example.

[Regarding the Cutting Method] The optical fiber core wire 10 is set in the z direction and pressed by the covering clamp 16 and the fiber clamps 18 and 20. The blade 22 is moved, and the optical fiber 1
A small scratch is given to the lower surface of No. 4. The pressing member 24 is pushed down in the y-direction, and a portion having a minute scratch is bent to give a tensile stress, and the brittleness of the glass is utilized to cause breakage from the minute scratch.

[0004]

There is an optical fiber doped with Ti or the like as a fiber protective layer on the surface of an optical fiber. In such a surface-reinforced fiber, compressive residual stress exists on the fiber surface. Therefore, there is a problem that even if a tensile stress is generated after a minute scratch is given to the surface of the fiber as described above, the fiber does not break, or it is difficult to form a perfect mirror surface even after the break.

[0005]

[Means for Solving the Problems] (1) Before the step of making the minute scratches, a method of removing the residual compressive stress of the optical fiber by heat treatment is adopted.

(2) As shown in FIG. 1, the cutting device is provided with a pair of electrodes 30 facing each other with the optical fiber 14 sandwiched therebetween, makes the electrodes 30 movable in the y direction, and presses the pressing member 24. The structure is such that it can be retracted from the moving range of the electrodes.

[0007]

[Operation] (1) By removing the residual compressive stress on the surface of the optical fiber, when a tensile stress is generated after giving a small scratch, the fiber is fractured and completely removed, just like a normal optical fiber. A mirror surface is obtained.

(2) By making the electrode 30 movable in the y direction, the electrode 30 does not interfere with the movement of the blade 22 and the pressing member 24. (3) By making the pressing member 24 retractable from the moving range of the electrode, the pressing member 24 does not hinder the movement of the electrode 30.

[0009]

[Explanation of cutting method] Releasing residual stress is similar to annealing in metal and annealing in plastic.
By heat treatment. Any heat source may be used for the heat treatment, but spark discharge (however, weak discharge) can be used as in the case of fusion of optical fibers.

Only the portion of the optical fiber to be cut needs to be heated by the weak discharge. The current (power) value of the weak discharge is set to a level that can give heat to the extent that the optical fiber does not melt and become thin. It may be the same level as the fiber cleaning performed prior to fusion bonding, but it differs depending on the magnitude of residual stress. The discharge time is about 0.2 seconds, for example. The discharge is
Depending on the magnitude of the residual stress, it may be performed not only once but also a plurality of times.

After the residual compressive stress is released, the blade 22 is moved to cause a minute scratch on the optical fiber 14 as in the conventional case, the pressing member 24 is pushed down in the y direction, and the portion where the minute scratch is given is bent to pull the tensile stress. To cut the optical fiber.

The condition of the weak discharge capable of releasing the residual compressive stress varies depending on the type of the optical fiber. Therefore, by experiments, the discharge power of weak discharge, discharge time, interval, number of times, etc. are properly selected.

[0013]

[Explanation of cutting device]

[Structure] (FIG. 1) Reference numeral 30 denotes a pair of electrodes for weak discharge, which are provided to face each other in the x direction with the optical fiber 14 interposed therebetween. 2 electrodes 3
0 is held in one electrode holder 32. The electrode holder 32 is configured to be movable in the y direction (the mechanism therefor is not shown). Reference numeral 34 is a discharge high voltage generator. When the electrode 30 moves in the y direction, the pressing member 24 can be retracted so as not to get in the way. For saving, the pressing member 24 may be movable in the x-direction (in addition to the y-direction), or the pressing member 24 may be attached to the tip of the arm to bend the optical fiber 14 when it falls. In addition, when standing up, the electrode holder 3
You may make it go out of the movement range of 2.

[Cutting Procedure] The optical fiber core wire 10 is set. The electrode holder 32 is lowered and moved to the fiber position (FIG. 2), and the residual stress is released by electric discharge. The electrode holder 32 is retracted upward (FIG. 3), and the blade 22 is moved to give a slight scratch to the optical fiber 14. The pressing member 24 is moved to the fiber portion (FIG. 4), and the optical fiber 14 is pressed and cut. Take out the cut optical fiber.

[0015]

Since the residual compressive stress of the optical fiber is released by the heat treatment, it is difficult to cut the fiber in the conventional case.
Even in a special fiber such as an i-doped fiber which has residual stress on the surface, it is possible to obtain a good cut surface of the conventional level. Further, since the coating material on the surface of the optical fiber can be evaporated by the electric discharge, it is also effective for cutting the optical fiber coated so as to stain or damage the cutting blade.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an embodiment of the present invention,
(A) is a plan view, (b) is a side view, and the C cross section is shown in (c).

FIG. 2 is an explanatory view of a state where the electrode holder 32 is moved to a predetermined position for weak discharge in the cutting procedure by the device of the present invention.

FIG. 3 is an explanatory view of a state where the optical fiber 14 is scratched by the blade 22 in the cutting procedure by the device of the present invention.

FIG. 4 is an explanatory view of a state where the pressing member 24 is moved to a predetermined position for pressing in the cutting procedure by the device of the present invention.

FIG. 5 is an explanatory view schematically showing a conventional cutting device,
(A) is a plan view, (b) is a side view, and the C cross section is shown in (c).

[Explanation of symbols]

10 Optical fiber core 12 Covered part 14 Optical fiber 16 coating clamp 18,20 Fiber clamp 22 blades 24 Pressing member 30 electrodes 32 electrode holder 34 High voltage generator for discharge

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mikio Yoshinuma             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Electric Wire Co., Ltd.             Company Sakura Factory

Claims (2)

[Claims] 1. A residual compressive stress of the optical fiber is obtained by heat treatment before cutting the optical fiber when a tensile stress is applied to the surface of the optical fiber after the surface is microscopically scratched to cut the optical fiber. How to cut an optical fiber so that 2. A plurality of clamps for fixing the ends of the optical fiber cores placed in the z direction, and between the two adjacent clamps, the clamps are movable in the x direction, and are attached to the optical fiber during the movement. An optical fiber cutting device comprising: a blade that gives a minute scratch; and a pressing member that is movable in at least the y direction and that applies tensile stress to the optical fiber by bending the optical fiber during movement. A pair of electrodes facing each other sandwiched between,
An optical fiber cutting device capable of moving the electrode in the y direction and retracting the pressing member from the moving range of the electrode.