JPH0160122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method for processing the end of an optical fiber for transmitting high-power laser light.

(1) Prior Art Generally, when transmitting high-power laser light through an optical fiber, it is important to reduce transmission loss not only by the material of the optical fiber but also by the optical condition of the end face of the optical fiber where the laser light enters. becomes important.
On the other hand, the input end of the optical fiber is provided with a base for connecting the input end to a laser oscillator or the like. The laser beam output from the laser oscillator is focused by a lens and enters the core of the optical fiber, but if the core and the end face of the base were flush, the slight deviation of the laser beam would cause As a result, the end face of the optical fiber is irradiated with the high-energy laser beam and melts, and the debris from this melts and adheres to the end face of the core, deteriorating the optical condition of this end face. It is made to protrude from the end face of the cap.

Conventionally, in order to perform such terminal processing on an optical fiber, the end face of the optical fiber was polished and then passed through a cap and held, or the optical fiber was passed through so that the end face was flush with the end face of the cap. After fixing these with adhesive and polishing their end faces together, the adhesive is removed to make the end of the optical fiber protrude from the adhesive, that is, to make it protrude inside the cap. was being carried out.

(2) Problems with conventional technology However, according to such conventional technology,
In the former case, when the optical fiber is passed through a hole that is slightly larger than the optical fiber drilled in the base, the polished end surface of the optical fiber often hits the base and is damaged. In addition, in the latter case, when removing the adhesive, not only the polished end face of the optical fiber is often damaged as in the former case, but also the disadvantage is that a great deal of labor is required to remove the adhesive. .

(3) Purpose of the Invention This invention provides a terminal treatment for an optical fiber that allows the end of the optical fiber to protrude inside a base without damaging the polished end face of the optical fiber. The purpose is to provide a method.

(4) Key Points of the Invention The end of the optical fiber from which at least the outer skin has been removed is inserted into a holding hole provided with a guide, and the end surface of the guide is flush with the opening surface of the holding hole. After the end face of the optical fiber passed through the drilled through hole is processed to be flush with the end face of the guide member, the guide member is removed or moved into the holding hole.

(5) First Embodiment of the Invention Figures 1 to 3 show a first embodiment of the invention. 1 in the figure is a cap. This cap 1 has a first holding hole 2 opened at one end surface in the axial direction of the cap 1.
and a second holding hole 3 opened at the other end surface, and these first and second holding holes 2 and 3 are connected to a communication hole 4.
communicated by. The second holding hole 3 is slightly larger than the outer diameter of the outer skin 5a of the optical fiber 5, and the communication hole 4 is slightly larger than the outer diameter of the cladding 5c covering the core 5b of the optical fiber 5. The first holding hole 2 is formed sufficiently larger than the second holding hole 3. A screw 6 is formed on the inner circumferential surface of the first holding hole 2, and a hollow cylindrical light shielding body 7 with one end closed and a guide body 8 are successively screwed onto the screw 6. The light shielding body 7 and the guide body 8
A first through hole 9 and a second through hole 10, which have approximately the same diameter as the communicating hole 4, that is, slightly larger than the outer diameter of the cladding 5c of the optical fiber 5, are formed in the . Furthermore, when the light shielding body 7 and the guide body 8 are screwed into the first holding hole 2, the length dimensions of these bodies are set so that the end surface of the guide body 8 is flush with the end surface of the first holding hole 2. ing. Note that a first holding hole 2 is formed on the end face of the light shielding body 7 and the guide body 8.
Engagement recesses 11 are respectively provided in which a tool (not shown) for attachment and detachment is engaged.

Further, on the other end side of the base 1 where the second holding hole 3 is provided, a stepped portion 13 having a screw 12 is formed on the outer peripheral surface, and a slot 14 is provided. A locking nut 15 is screwed onto the stepped portion 13, and the inner peripheral surface of the locking nut 15 and the tip of the stepped portion 13 are provided with corresponding tapered walls 15a, 13a. Therefore, by screwing in the locking nut 15, the peripheral wall of the second holding hole 3 is elastically deformed in the radial direction.

In order to attach the thus configured cap 1 to the end of the optical fiber 5, first remove the outer skin 5a of the end of the optical fiber 5 to a predetermined length as shown in FIG. is inserted from the second holding hole 3 into the first holding hole 2 via the communication hole 4. And the outer skin 5
The part where the outer skin 5a is removed is placed in the second holding hole 3, the part where the outer skin 5a is removed is placed in the first holding hole 2, and the tip is placed in the light shield 7.
The guide body 8 is made to protrude from the base 1 through the first and second through holes 9 and 10 of the guide body 8. And lock nut 1
5 to fix the optical fiber 5 to the base 1. A scattering section 16 for scattering light is formed in a portion of the optical fiber 5 located within the hollow portion of the light shielding body 7 by applying a satin finish to the outer peripheral surface of the cladding 5c in advance.

Next, the portion of the optical fiber 5 that protrudes from the guide body 8 is removed by polishing, and the end surface is replaced with a second one.
As shown in the figure, it is polished so that it is flush with the end surface of the guide body 8. In the final stage of this polishing process, this end surface and the end surface of the optical fiber 5 are polished together using the end surface of the guide body 8 as a guide surface. Then, since the end face of the optical fiber 5 is polished so as to become a part of the end face of the guide body 8, the parallelism and flatness of the optical fiber 5 become optically good. In addition, at this time, the locking nut 15
The optical fiber 5 may be fed out after being loosened, and the optical fiber 5 may be polished more than the end surface of the guide body 8.

Once the end face of the optical fiber 5 has been finished in this way, the guide body 8 is removed from the first holding hole 2 using a tool (not shown), and the tip of the optical fiber 5 is shown in FIG. It can be made to protrude from the light shielding body 7 as shown in FIG. That is, the tip of the optical fiber 5 can be made to protrude within the first holding hole 2. Moreover, when the guide body 8 is removed, the polished end face of the optical fiber 5 is not damaged.

As shown in FIG. 3, the laser beam L focused by the lens 17 is incident on the optical fiber 5 to which the base 1 is attached in this manner. And laser light L
If the optical axis of the optical fiber 5 were misaligned with the axis of the optical fiber 5, a part of the laser beam L would irradiate and melt the end face of the light shielding body 7, but the end of the optical fiber 5 would not be exposed to light. Since it protrudes from the end face of the optical fiber 5, melted and scattered objects from the light shielding member 7 will not adhere to the end face of the optical fiber 5. In addition, since the laser beam L that deviates from the end surface of the optical fiber 5 is blocked by the end surface of the light shielding body 7, the outer skin 5a made of a combustible material that covers the cladding 5c of the optical fiber 5 is not damaged. . Furthermore, since the tip of the optical fiber 5 protrudes from the end surface of the light shielding body 7 within the first holding hole 2, the periphery of the tip is covered with the peripheral wall of the first holding hole 2, making it easy to handle. There is no possibility that the tip of the optical fiber 5 will be damaged by being hit by an object.

(6) Other embodiments of the invention FIGS. 4 to 6 show second to fourth embodiments of the invention.

First, in the second embodiment shown in FIG.
The core 5b is also removed to expose the core 5b, and the other configurations are the same as in the first embodiment.

The third embodiment shown in FIG.
Only the guide body 18 was provided. The length of this guide body 18 is shorter than the depth of the first holding hole 2, and a groove 19 is formed on the outer peripheral surface of the guide body 18.
9 is a screw 2 screwed into the peripheral wall of the first holding hole 2.
0 is engaged. That is, by loosening this screw 20, the guide body 18 becomes movable in the axial direction of the first holding hole 2.

When polishing the tip end surface of the optical fiber 5, the guide body 18 is fixed so that the end surface is flush with or protrudes from the opening surface of the first holding hole 2, and when the polishing process is completed, The guide body 18 is moved into the first holding hole 2 as shown by the chain line in the figure, so that the tip of the optical fiber 5 projects from the end surface of the guide body 18.

According to the cap 1 having such a structure, the guide body 18 can be used also as the light shielding body 7 shown in the first embodiment, and the end surface of the guide body 18 is polished. It becomes a mirror surface and the reflectance to the laser beam L improves, so the laser beam L
Even if it is irradiated with water, it will not melt easily.

In the fourth embodiment shown in FIG. 6, a holding hole 21 having approximately the same diameter as the outer skin 5a of the optical fiber 5 is bored over the entire axial length of the base 1, and a core 5 is inserted into the holding hole 21.
A guide body 23 having a through hole 22 slightly larger than b is provided so as to be freely movable. Further, a first screw 24 capable of fixing the guide body 23 and a second screw 25 capable of fixing the outer skin 5a of the optical fiber 5 are screwed into the peripheral wall of the base 1.

According to such a configuration, the end surface of the guide body 23 is made flush with or protrudes from the opening surface of the holding hole 21 and the optical fiber 5 is polished, as in the third embodiment shown in FIG. The body 23 may be moved into the holding hole 21.

(7) Effects of the Invention As described above, the present invention is capable of inserting at least the end of an optical fiber from which the outer skin has been removed into a guide hole provided with a guide body, and inserting the end portion of an optical fiber from which the outer skin has been removed into a guide hole provided with a guide body. After processing the end face of the optical fiber passed through so that it is flush with the end face of the guide body, the guide body is removed or moved into the holding hole. A cap can be attached to an optical fiber without performing work that may damage the end face.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a cross-sectional view of an optical fiber inserted into the base, FIG. 2 is a cross-sectional view of the optical fiber protruding from the base, and polished. FIG. 3 is a sectional view showing the tip of the optical fiber protruding into the holding hole, and FIGS. 4 to 6 are sectional views of a base showing second to fourth embodiments of the present invention, respectively. 1...cap, 2,3,21...retaining hole, 5...
Optical fiber, 5a...outer skin, 5c...cladding,
5b... Core, 8, 18, 23... Guide body, 9,
22...Through hole.

Claims (1)

[Claims] 1. At least the end of the optical fiber from which the outer skin has been removed is inserted into a holding hole opened in the end face of the base, and a guide is provided in which a through hole slightly larger than the end of the optical fiber is bored in the holding hole. Set up your body,
A method for processing the end of an optical fiber, which comprises processing the optical fiber passed through the through hole so that its end surface is flush with the end surface of a guide, and then removing or moving the guide into the holding hole.