JPH06186435A - Method for removing coating material of optical fiber - Google Patents

Abstract

PURPOSE:To perform the processing in a short time without damaging an optical fiber by irradiating the optical fiber with a laser light over a prescribed length along which a coating material is to be removed and removing the coating material. CONSTITUTION:A laser light source LD1 5 for machining use is provided in the upper part of an optical fiber 1. The output power, the time interval of an irradiation pulse and the repeating period of the LD1 5 are set by means of a controller 6. In such a case, while the laser light source LD1 5 is made to continuously oscillate with a prescribed output and the sample being a machining object is gradually moved at a prescribed speed from a distant position far from the focus, by bringing the sample into the coverage 8 for laser beam irradiation and taking the sample out of the coverage 8 for irradiation after the termination of machining, the energy density is controlled. Namely, by irradiating the prescribed part of the optical fiber 1 with the laser light, the coating material 2 is removed over the length L without damaging the glass part (core 4 and clad 3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a material to be covered provided on an outer peripheral portion of an optical fiber.

[0002]

2. Description of the Related Art Generally, when processing an optical fiber and assembling an optical demultiplexer, the glass base material is exposed by removing the base material such as nylon or UV material covering the glass base material. The process of making it necessary.

Conventionally, the process for removing the covered cloth has been carried out by shaving off a predetermined portion using a knife or the like.

FIG. 1 shows a conceptual diagram of the structure of an optical fiber. The optical fiber 1 includes a glass part matrix composed of a core 4 and a clad 3 and a covered material 2 such as nylon or UV resin material.
Have been covered with.

FIG. 2 is a view showing a state in which the material to be covered has been removed. At approximately the center of the optical fiber 1 that has been cut to a predetermined length, the material to be covered 2 of the length L
Are removed. In the portion having the length L, the clad 3 constitutes the exposed portion 31. When the exposed portion 31 is formed, it is conventionally performed by hand such as cutting with a sharp blade such as a knife or a razor, and it requires a large amount of manpower, and force is applied during cutting, so the outer diameter When handling a thin optical fiber of about 125 μm, the clad 3 often breaks. Also, since it is a manual work, the work time is several minutes or more.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to prevent breakage of an optical fiber in the step of removing the covering material of the optical fiber, and to further speed up the work.

[0007]

That is, the present invention provides a method for removing a covered material of an optical fiber by irradiating an optical fiber with laser light for a predetermined length to remove the covered material, The present invention provides a method for removing an optical fiber covering material, which is characterized by removing the covering material.

The present invention takes advantage of the fact that there is a difference in the temperature of combustion of the material of the material to be covered 2, the evaporation temperature T ₁ , and the lower melting temperature T ₂ of the clad 3 and the core 4 of the optical fiber. Then, without mechanically applying a force to the optical fiber, laser light is applied to the portion to be covered by the removal to remove the material to be removed by burning and vaporizing the portion.

As described above, since the material to be covered is burned and vaporized by the irradiation of the laser beam, no mechanical stress is applied to the optical fiber, and the optical fiber is not broken and the processing is performed in a short time. Can be done. for that reason,
It is also effective for automating production and improving yield.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The constitutional concept of the principle of the present invention is shown in FIG. Processing laser light source LD ₁ 5 on top of the optical fiber 1 is provided. The controller 6 sets the output power of the LD ₁ , the irradiation pulse time width, and the repetition cycle. The spatial positional relationship between the LD ₁ and the optical fiber 1 is appropriately set depending on the melting point of the material to be covered 2, the processing accuracy required for the portion to be covered L to be removed, and the like. That is, generally, the laser light is focused by the lens 7 provided at the output part of the LD ₁ . At the focal point F, the energy density of the laser light becomes highest. Then, when viewed from the lens 7, the beam diameter of the laser light in the area closer to the focus F is LD ₁ at the maximum.
Up to the direct output beam width of. Therefore, when the output power of LD ₁ is constant, the optical fiber 1 is
As the focal point F is moved closer to the lens 7 of the LD ₁ , the irradiation energy density of the laser light gradually decreases and saturates at a certain value.

On the contrary, the case where the fiber 1 is set at a position farther than the focal point F in the beam irradiation cover area 8 will be described below. In this case, the irradiation energy density becomes maximum at the focal point F, and as the distance from the focal point increases,
It will decrease toward zero without limit.

It is necessary to properly use such characteristics in the positional relationship in the case of processing by laser light.

That is, there are roughly two ways of operating the laser light source during laser processing, and it is necessary to properly use the above-mentioned positional relationship depending on each case.

The first operation method is a method in which the laser light source is constantly oscillated (continuous operation) and the output thereof is adjusted to a desired energy density by using a shutter, a reducer or the like each time processing is performed.

In the second operation method, the laser light source is continuously oscillated at a predetermined output, and the sample to be processed is gradually moved at a predetermined speed from a position far from the focal point while the laser beam is emitted. This is a method of controlling the energy density by bringing the material into the irradiation cover area 8 and further bringing it out of the irradiation cover area after the processing is completed. Also in this case, if the means for adjusting the laser light output itself is also used, the processing performance is further improved.

The first method is to increase the cost of the device,
There are drawbacks such as deterioration of parts. From this point of view, the second method is economical.

By irradiating a predetermined portion of the optical fiber 1 with laser light by such a method, the covering material 2 is removed over the length L while leaving the glass portion (core 4 and clad 3) intact. You can

FIG. 4 shows an example of the system configuration when two laser light sources are used. A second laser light source LD ₂ 51 and its control device 61 are also provided.

In this case, the mutual positional relationship must be set so that the beam 9a of LD _{1 and} the beam 9b of LD ₂ do not irradiate other laser devices.

In the case of FIG. 4, when realizing the principle of the second operation method, the positional relationship between the laser output unit 5 and the same 51 with respect to the optical fiber 1 is adjusted by spatially moving each.

FIG. 5 shows an example of the configuration of a system when three laser light sources are used. Three laser light sources LD ₁ 5, LD ₂ 5
1, LD ₃ 511 are provided about the optical fiber 1 at an angle of approximately 120 °. By arranging the laser light source in this way,
It is possible to irradiate a laser beam having a more uniform energy density.

Also in this case, the irradiation energy density for the sample can be controlled by moving the position of the laser.

When the surface of the clad of the optical fiber from which the covering has been removed by the laser light is attached to the carbonaceous substance or other substance such as mottle, it should be washed with a solvent or the like. Can be easily removed by. Further, according to the experiment, the time required for removing the covered cloth up to a length of about 5 mm was within 1 second.

[0024]

As described above, the working time can be shortened because the coating material covered with the laser beam can be instantly removed combustively or evaporatively. In addition, since the method does not involve stress application, the production yield does not decrease due to fiber breakage, etc., which is effective in automating the process and reducing costs.

[Brief description of drawings]

FIG. 1 shows a model structure diagram of an optical fiber to be processed.

FIG. 2 is a model diagram of a sample after processing.

FIG. 3 is a conceptual diagram of a system of an apparatus for partially removing a covered portion by irradiating a laser.

FIG. 4 is an explanatory diagram of a system configured by using two laser light sources.

FIG. 5 is an example configured by using three laser light sources.

[Explanation of symbols]

 1: Optical fiber 2: Material to be shielded 3: Cladding 4: Core 31: Cladding of the portion where the material to be shielded is removed. 5: Laser 7: Lens 8: Beam F: Focus

Claims (1)

[Claims] 1. A method for removing a covered material of an optical fiber, characterized in that the covered material is removed by irradiating the optical fiber with laser light over a predetermined length to remove the covered material. Optical fiber material removal method.