JPH033204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making an improved optical fiber support for use in coupling devices for optical fibers, fiber optic cables, and the like.

Optical transmission lines used for testing and measurement of optical communication systems and optical circuits are made of optical glass or plastics with different refractive indexes and a predetermined refractive index, and are used as a core and cladding layer with a predetermined cross-sectional dimension. (hereinafter referred to as optical fiber), a protective coating layer made of synthetic resin such as silicone or urethane is formed on the outside, an intermediate layer consisting of a fiber layer such as polyimide resin (trade name nylon) as a reinforcing material, and further There are optical fiber cables whose exterior is made of a jacket layer integrally extruded from a material such as polyethylene or vinyl, and small-diameter optical fiber cords whose optical fibers are coated with resin.

When such an optical fiber such as an optical fiber cable or cord is coupled to a main part of a device or another optical fiber with its end faces facing each other, the optical fiber end is connected to an optical fiber coupling device.

When connecting optical fibers to an optical fiber coupling device, the optical fibers have a small diameter, so it is necessary to position them correctly and connect them so that there is no optical axis misalignment between them. The constituent members of an optical fiber coupling device, particularly the optical fiber support (core), are required to have very strict dimensional accuracy. Therefore, parts manufactured by conventional machining or the like are inevitably expensive due to yield issues and are not efficient.

For example, as shown in FIG. 1, an optical fiber is fixed to a jack body 11 constituting a jack 1 and a plug 2 as an optical fiber coupling device, and a plug body 21 having a bag nut 22 and a retaining ring 23 fitted to the outside. Optical fiber support (core) 3,
3' is inserted, and the clampers 4, 4' to which rubber boots 5, 5' are respectively attached are screwed and fixed by tightening from the back side of the large outer peripheral parts 30, 30' of the supports 3, 3'. There is.

The reference outer peripheral portion 31 of one optical fiber support 3 of this optical fiber coupling device is fitted into the reference hole 12 of the jack body 11 and positioned by a stepped portion 33, and the protrusion of the other optical fiber support 3' The end faces 34 and 34' of the optical fibers are fitted into the reference hole 12 of the jack body, and the end surfaces 34 and 34' of the optical fibers are brought into contact with each other, and the ends of the optical fibers located at the center of each are connected.

As shown in FIG. 2, the optical fiber support 3 conventionally has a hole into which the outer diameter of the optical fiber cable 6' can be inserted from the large-diameter end 30 of the support, and an outer diameter 31 on the coupling end side. A support made by cutting a hole 32 that is concentric with the optical fiber and that exactly fits the optical fiber, or a support that has an appropriate hole 32' in the center as shown in Figure 3. Insert the optical fiber cable 6'' with the optical fiber exposed at the end, adjust the position of the optical fiber so that it is concentric with the reference outer diameter 31 of the support, and fix with adhesive. etc. were hot.

In the former case, even though the drilling process was performed with high precision through cutting, only short lengths could be obtained at that part, so the outer diameter of the optical fiber 69 and the hole were changed as shown in FIG. Due to the difference in inner diameter of 32, it is impossible to prevent the axis B of the optical fiber from being tilted with respect to the axis A of the hole. The latter method is not suitable for connecting optical fibers quickly or in large quantities because the workability of centrally positioning the optical fibers is poor.

In view of the above points, an object of the present invention is to provide a method for manufacturing a support for an optical fiber coupling device, which is provided with a hole through which an optical fiber can be inserted and supported correctly in the center. A wire core material made of a hard circular cross-sectional material with a predetermined dimension so that the diameter of the cross section matches the diameter of the optical fiber and to form a desired hole diameter through which the optical fiber can be inserted is made of a metal having an appropriate wall thickness. inserted into the inside of the tubular member,
Next, the intermediate portion of the tubular member is compressively deformed from the outside in at least three directions equally spaced in the direction of the core material into a concave shape having a predetermined axial length, and the internal shape of the tubular member at the portion based on the deformation is changed to that of the core material. a step of cutting the compressively deformed portion of the tubular member along a plane perpendicular to the axial direction and making the portion where the inner diameter of the tubular member has the desired hole diameter dimension as an end face; With the small diameter hole of the hole as a reference, the outer diameter of the tubular member including the protrusion that can be deformed and protruded between the recesses due to the compressive deformation of the outer diameter of the tubular member is coaxial with the axis of the small diameter hole and has a circular outer diameter of a uniform predetermined dimension. a polishing process;
The above object is achieved by including the step of attaching a flange positioned in axial abutment to the other end side of the end face.

An embodiment of the method for manufacturing a support for an optical fiber coupling device according to the present invention will be described below with reference to the drawings.

FIG. 5 shows an example of the manufacturing process of an optical fiber support according to the method of the present invention, shown in a to e. In the figure, a is a hard metal core material 50 with a circular cross section, such as a piano wire or tungsten wire that has been hardened and polished so that its outer diameter is equal to the diameter of a predetermined optical fiber, and is shaped into a tubular shape with an appropriate wall thickness. The member 51 is inserted into, for example, a stainless steel pipe having an inner diameter 52 larger than the outer diameter of the core material 50, and the parts protruding on both sides are gripped and pulled and fixed in the directions of arrows A and A'.

Next, the intermediate part 53 of the tubular member 51 shown in figure b is
A predetermined length 53 is set in the axial direction from the outer periphery of the core material 50 from the three directions of arrows C, C, and C at equal intervals as shown in Figure c using a three-direction movable type press (not shown). It has compression plastic deformation. Then, the outer shape of the tube 51 bulges outward at the portion where the inner shape is equal to the outer diameter of the core material 50 and the adjacent pressed boundary portion, and the inner shape of this portion is exactly the same as the crack-shaped portion 5.
4 parts are formed, and most of the part corresponding to the core material 50 is circular.

The core material 50 is extracted from the deformed pipe member 51, and its outer shape (indicated by imaginary lines) is oriented as shown in Figure d, and the left inner diameter portion 55 is inserted into the small diameter hole 56 by the core material 50. It is cut at the position where the formed part is formed, and the outer diameter is coaxial with the axis of the small diameter hole 56 as a reference, and a circular polished surface 57 is formed to have an outer diameter of a uniformly precise desired size.

Regarding the above-mentioned polishing finish, although not shown, the pipe member 51 is conveyed between the conical non-rotating centers facing each other on the same axis of the polishing device, and the small diameter hole 56
and large-diameter hole 52, the center is brought close to insert the conical tip of the center, and the tube member 51 is positioned so as not to move in the axial direction.

By rotating the face plate of the polishing device, which has passed through one end of the tube member 51, as the automatic centrifugal chuck provided on the face plate rotates, the chuck grips and holds one end of the tube member 51. Rotate. As the tube member 51 rotates, a rotary grindstone is applied to the outside of the tube member 51 to perform polishing.

The small diameter hole 56 and the large diameter hole 52 are coaxial, and both centers are coaxial and non-rotatable, so there is no cause for misalignment. By performing external polishing with the central axes of the small-diameter hole 56 and large-diameter hole 52 as a reference as described above, the hole 56 and the outer surface 57 are polished.
It is possible to obtain a precision product with extremely high concentricity of both axes. Of course, rough polishing and final polishing can be performed depending on the process. These processes can be carried out by automated equipment, such as robotic equipment, which does not require human labor.

The core material 50 is extracted from the deformed pipe member 51, and as shown in FIG. At the same time, the small diameter 56 is used as a reference, and the outer diameter is coaxially and uniformly polished to a desired size with a circular polishing finish 57.

A flange 35 is press-fitted into the outer diameter end of the tubular member thus obtained, that is, the optical fiber support 58, as shown in Fig. Alternatively, if they are fixed by adhesive or the like, a small optical fiber coupling device can be constructed as the optical fiber support 3 by attaching an optical fiber (not shown). Of course in this case 57
is the reference outer diameter. In addition, a step portion with a small diameter is formed in advance on the end side of the optical fiber support 58,
A flange with a straight inner diameter may be press-fitted into this stepped portion, and this can be selected and implemented as appropriate in terms of design.

In any of the above cases, the bare optical fiber portion is inserted into the small diameter hole 56, and the coated portion of the optical fiber is inserted into the portion of the hole 52 that is not compressed, and the optical fiber (not shown) and the optical fiber support 58 are bonded and fixed. The end face of the optical fiber is polished to make the end of the optical fiber optically flat.

The small diameter hole 56 is several μm different from the outer diameter of the optical fiber.
It is easy to obtain an inner diameter dimension that allows accurate insertion into a gap of less than 100 degrees. This can be done by selecting and determining the diameter of the core material 50 in advance to a predetermined size so that the inner diameter of the small diameter hole 56 formed when the tube member 51 is compressed and deformed has the desired size. That's true.

As described above, according to the method of the present invention, a highly accurate optical fiber support can be produced with great precision and ease. The core material 50 may be used repeatedly or only once, and due to the hardness of the material, it will not deform when compressed. Then the inner diameter is 56
The length portion 53 can be arbitrarily determined by the core material 50, and when the diameter of the optical fiber is about 100 μm, a length of 1 mm or less can be obtained by conventional drilling, but by the method of the present invention, a length of 1 mm or less can be obtained. Since it can be easily manufactured with a length of just a few millimeters and a precise inner diameter, the end of the optical fiber can be supported stably with little inclination.

The core material 50 may be extracted after being cut at a portion that is to become an end surface in the process shown in Figure d, and in such a case, deformation of the inner diameter is prevented.

In addition, in the case shown in figure e, especially d
In the drawing process, the outer diameter is first roughly finished, then barrel processing is performed to smooth the corners of the outer shape and remove burrs, etc., then a slight finishing polishing process is performed, and the final barrel processing is performed again. These barrel processing steps deburr and smooth the external surface, round the corners, and harden the surface.

In addition, suitably heat-treating the tubular member before compression deformation, during the compression process, after deformation, etc. brings good results in terms of improving the dimensional stability of the tubular member.

As shown in FIG. 6, if an adapter 37 is used which has screws 36, 36' formed at both ends of a flange 61 in the middle of the outer periphery, the optical fiber supports 3, 3' can be inserted facing each other from both sides, and then tightened with a suitable bag-shaped nut. If tightened, it can be configured as an optical coupling device.

It goes without saying that in any of the above-mentioned cases, the method of the present invention may be such that the deformation stage of the tubular member is not set at the desired inner diameter from the beginning, but is deformed and formed step by step, and the desired diameter is achieved at the final stage. There is no such thing.

As described above, the method of the present invention involves inserting a hard metal core having a circular cross section into a softer tubular member, compressing the tubular member from the outer periphery in the direction of the core, and plastically deforming the tubular member. A hole is obtained in which the inner diameter of the member is set to a desired size depending on the outer diameter of the core material, and the formed inner diameter portion forms one end surface, and the shape and size of the outer shape are formed. A precise and long hole can be manufactured by compression means such as a press, the outer shape can be accurately positioned relative to the inner diameter hole appearing on the end surface, and a flange can be provided integrally. Therefore, it can be used in optical fiber coupling devices with excellent effects.

[Brief explanation of drawings]

FIG. 1 shows an example of a pair of optical fiber coupling devices in sectional side views of the jack side and the plug side, respectively.
2 and 3 are side sectional views of a conventional optical fiber support, FIG. 4 is a sectional view of a main part illustrating the insertion state of a conventional optical fiber, and FIG. 5 is a manufacturing method of the support according to the method of the present invention. An example in which processes are shown in a to e, and FIG. 6 is a side sectional view of the adapter. In the figure, 1 is a jack, 2 is a plug, 3 is an optical fiber support, 6 is an optical fiber cable, 69 is an optical fiber, 11 is a jack body, 12 is a reference hole,
Reference numeral 31 designates a reference outer peripheral portion, 50 a core material, 51 a tubular member, 53 a compressed portion, and 58 an optical fiber support.

Claims (1)

[Claims] 1. A linear core material made of a hard circular cross-sectional material with a predetermined size and an appropriate wall thickness so that the cross-sectional diameter matches the diameter of the optical fiber and to form a desired hole diameter through which the optical fiber can be inserted. It is inserted into the inside of a metal tubular member, and then the intermediate part of the tubular member is compressively deformed from the outside in at least three directions equally spaced in the direction of the core material into a concave shape having a predetermined axial length to prevent the deformation. a step of making the internal shape of the tubular member match the external dimension of the core material; and a step of cutting the compressively deformed portion of the tubular member along a plane perpendicular to the axial direction so that the inner diameter of the tubular member is the desired hole size. is the end face, and the outer diameter including the protruding part that can be deformed and protruded between the recesses by the compressive deformation of the outer diameter of the tubular member is coaxial with the axis of the small diameter hole, with the small diameter hole of the desired hole diameter part of the end face as a reference. and a step of circularly polishing the outer diameter to a uniform predetermined size, and a step of attaching a flange positioned in axial abutment to the other end side of the end face. Method for manufacturing a support.