JPH0565847B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for polishing the end face of a PC (Physical Contact) type optical fiber connector.

<Prior art> Various types of optical fibers have been considered for connecting optical fibers to each other, but the so-called PC (Physical Contact) type has a ferrule made of ceramics and a connector end surface polished into a convex curve. Optical fiber connectors are attracting attention because of their strength and characteristics. The end face of this PC type optical fiber connector, especially the end face of the optical fiber to be connected, needs to be shaped into a convex curved surface with high precision and high quality.

A flowchart of the conventional manufacturing process of this PC type optical fiber connector is shown in FIG. 4, and a cross-sectional view of the optical fiber connector in each process is shown in FIG. As shown in Figures 4 and 5, in the conventional manufacturing method of PC type optical fiber connector, first, the optical fiber 1 is
1, and has an insertion hole 13 for inserting the end face 15.
After preparing a flat ceramic ferrule 17 having a flat shape and injecting thermosetting adhesive 19 into its insertion hole 13, the optical fiber 11 is inserted into the insertion hole 13 and fixed (fifth Figure a). Next, using a knife edge such as saphire, the excess optical fiber 11 protruding from the adhesive 19 is cut off (the state shown in FIG. 5b). continue,
After the adhesive 19 is removed by grinding with a flat grindstone or lapping with a flat lapping plate to make the end surface 15 flat as shown in FIG. 5c, the end surface 1
5 to obtain a convex spherical end surface 21 (the state shown in FIG. 5d).

Some spherical processing involves a two-step process in which the shape is prepared in pre-processing and then finished.
In the meantime, intermediate finishing processing may be employed. In the pre-processing, a grindstone or lap plate with a convex spherical surface corresponding to the convex spherical surface of the connector end face 21 is used. Furthermore, for intermediate finishing and finishing, a soft metal plate shaped into a concave spherical shape is similarly used, and polishing is performed while supplying fine diamond particles mixed with a liquid. In order to obtain excellent optical transmission characteristics as an optical fiber connector, the ferrule end face 21 is finally made into a convex spherical shape whose apex coincides with the center of the optical fiber 11, as shown in FIG. The end face of the optical fiber 11 is made into a distortion-free mirror surface.

FIG. 6 is a conceptual diagram of this type of conventional spherical surface machining apparatus. Conventionally, as shown in FIG. 6, the surface of a surface plate (plate) 23 serving as a tool is formed into a predetermined concave spherical surface, and the ferrule 17 is attached to a holder 25 so that its central axis is aligned with the center of the spherical surface of the surface plate 23. The end face of the ferrule 17 is rotated and swung along the concave spherical surface of the surface plate 23 using the holder 25, which is a so-called grinding motion, and the ferrule 17 and the surface plate 23 are The polishing process is performed by supplying a working fluid containing diamond fine particles to the sliding surface from the nozzle 27.

<Problems to be Solved by the Invention> However, the above-mentioned conventional technology has the following problems.

(1) As explained in Figures 4 and 5, the process is extremely complicated, and cleaning is required after each process, resulting in poor work efficiency and the difficulty of finishing a single connector. I spent over 30 minutes on it. Furthermore, it is necessary to pay sufficient attention to the management of the surface plate 23 during the polishing process, and the surface plate 23 must be regularly
3 corrections had to be made, which was very complicated.

(2) Since connectors are made of different materials such as hard ceramics, soft quartz glass, and adhesives, there may be differences in the amount of processing for each material during final polishing due to the differences in the materials. This causes a step to occur at the boundary between the optical fiber 11 and the ceramic ferrule 17 at the end face 21. That is, since the optical fiber 11 is softer than the ceramic ferrule 17, a portion of the optical fiber 11 is shaved too much and is recessed by about 1 to 0.5 μm from the end face of the ceramic ferrule 17.
As an optical fiber connector, it has been a major obstacle in the transmission of optical signals.

The present invention solves these conventional problems, and is a method for polishing optical fiber connectors that simplifies the manufacturing process of optical fiber connectors and allows high-precision, high-quality optical fiber connectors to be obtained. The purpose is to provide a method.

<Means for Solving the Problems> A method for polishing an optical fiber connector according to the present invention that solves the above problems is a method for polishing the end face of a PC type optical fiber connector, in which a ceramic ferrule having an optical fiber insertion hole in the center is used. The end face of the ceramic ferrule is polished into a convexly curved surface in advance, and the optical fiber is inserted into the optical fiber insertion hole of the ceramic ferrule so that the end face slightly protrudes from the convexly curved end face. The ferrules are fixed to each other with adhesive, and then the end face of the ceramic ferrule from which the optical fiber protrudes is pressed against a polisher surface while holding the longitudinal axis perpendicular to the polisher surface to remove the optical fiber. The method is characterized in that the fiber end face is polished until it substantially coincides with the position of the convex curved end face of the ceramic ferrule.

<Function> The polishing operation only needs to be performed on the optical fiber protruding from the ceramic ferrule, and this can be easily done by pressing the optical fiber perpendicularly to the polishing surface and bringing it into sliding contact. Further, the convex curved end surface of the ceramic ferrule, which is harder than the optical fiber, acts as a stopper for the progress of processing when polishing the protruding portion of the optical fiber.

<Examples> Examples of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a sectional view of an optical fiber connector at each step of a polishing method according to an embodiment of the present invention. As shown in FIG. 1, in this method, first, a ceramic ferrule 33 is prepared, the end surface 29 of which has been polished into a convex curved surface, for example, a spherical shape, and in which an optical fiber insertion hole 31 is bored in the center. Then, the adhesive 19 is injected into the optical fiber insertion hole 31 of the ceramic ferrule 33 and the optical fiber 11 is inserted. 11 and the ceramic ferrule 33 are fixed to each other (the state shown in FIG. 1a).

Next, the end face 29 of the ceramic ferrule 33
Extra optical fiber 11 and adhesive 1 protruding from
Rough processing is performed to scrape off the optical fiber 11, leaving the optical fiber 11 slightly protruding from the end face 29 (Fig. 1b).
condition). This rough processing can be performed by grinding, lapping, polishing, or the like. Note that this rough processing step can be omitted if the initial protrusion amount of the optical fiber 11 and the amount of adhesive buildup are small, and the next final polishing step can be performed without going through the rough processing step. good.

Next, from the state shown in FIG. 1b, the end surface 29 of the ceramic ferrule 33 is pressed against the polisher surface so that its longitudinal axis is perpendicular to the polisher surface, so that the end surface of the optical fiber 11 is aligned with the ceramic ferrule 33. The polishing is performed until it coincides with the end surface 29 of , and the polishing is completed (the state shown in FIG. 1c).

FIG. 2 is a conceptual diagram showing an example of a specific polishing apparatus for carrying out the method of the present invention. As shown in FIG. 2, a rough machining rotary surface plate 37 and a finishing machining rotary surface plate 39 are arranged adjacent to each other in the device casing 35 so as to be freely driven and rotatable. and rotating surface plate 39 for finishing processing
A fine diamond grindstone 41 and a relatively hard polisher 43 for finishing are attached to the upper surface of each of the wheels. Further, above the rough machining rotary surface plate 37 and the finishing machining rotary surface plate 39, a grinding fluid supply nozzle 45 and a processing agent (polishing agent) supply nozzle 47 in which fine abrasive grains are dispersed in pure water are provided, respectively. It will be done. Furthermore, a chuck 49 for holding the ceramic ferrule 33 is disposed above both rotating surface plates 37, 39. The check 49 holds the ceramic ferrule 33 so that its longitudinal axis is perpendicular to the upper surface of the fine diamond grinding wheel 41 and the polisher 43 on the upper surfaces of the rotating surface plates 37 and 39, and the chuck 49 itself rotates around its longitudinal axis. It is freely rotatable and movable in the lateral direction parallel to the upper surface of the fine diamond grindstone 41 and the upper surface of the polisher 43 on the upper surfaces of the rotary surface plates 37 and 39.

To use this device, first hold the ceramic ferrule 33 to which the optical fiber 11 is fixed in the chuck 49 as described above, position it on the fine diamond grinding wheel 41, and place the ceramic ferrule 33 on the end face 29.
The optical fiber 11 protruding from the surface is pressed against the fine diamond grindstone 41 with a predetermined pressing force. At the same time, while supplying grinding fluid from the grinding fluid supply nozzle 45, the rotary surface plate 37 and the chuck 49 are rotated, and the chuck 49 is connected to the fine diamond grinding wheel 4.
The optical fiber 11 is reciprocated in the lateral direction within a range of 1, and rough processing is performed to remove protruding optical fibers 11 and bulges of adhesive 19. In this rough machining, as mentioned above,
The optical fiber 11 and adhesive 19 are left slightly protruding from the end face 29 of the ceramic ferrule 33, for example, by about 5 μm.

Next, while holding the rough-processed ceramic ferrule 33, the chuck 49 is moved onto the adjacent polisher 43, and it is similarly pressed against the polisher 43, and a processing agent is supplied from the processing agent supply nozzle 47. While applying rotation and reciprocating motion similar to rough processing, the protruding portions of the optical fiber 11 and adhesive 19 left in the rough processing are removed by polishing.
The end face is the end face 2 of the ceramic ferrule 33.
Match position 9. In this case, since the ceramic ferrule 33 is harder than the optical fiber 11, by appropriately selecting a processing agent, the end surface 29 of the ceramic ferrule 33 can be made into the optical fiber 11.
It can also function as a stopper for the progress of processing (polishing) of the adhesive pair 19. That is, by using a processing agent that can be polished to a large extent for the optical fiber 11 and the adhesive 19 but hardly for the hard ceramic ferrule 33, the end faces of the optical fiber 11 and the ceramic ferrule 33 can be aligned by simply pressing them against the polisher 43. It is possible to do so. Here, examples of this type of processing agent include SiO ₂ , CeO ₂ ,
Fine particles such as Fe ₂ O ₃ , TiO ₂ , ZrO ₂ are preferable.

FIG. 3 is an example of a cross-sectional view of the tip of an optical fiber connector finished in this manner.As shown in FIG.
1 and the ceramic ferrule 33 can be polished with almost no step. According to experiments, the optical fiber 11 has a convex shape of 0.01 μm or less or 0.05 μm with respect to the ceramic ferrule 33.
It has been found that polishing can be performed within the following concave precision range, and the processing time per piece was able to be shortened to about 5 to 10 minutes.

In addition, the above-mentioned fine-grain diamond grinding wheel 4 for rough processing
1 is preferably a resin-bonded or metal-bonded diamond grindstone, and a relatively hard polisher 43 for finishing is suitable, such as cloth, polyurethane-impregnated nonwoven fabric, plastic (polyethylene fluoride, acrylic, vinyl chloride, etc.).
Nylon, etc.) are good.

Further, in the above example, the polisher 43 is attached to the upper surface of the rotary surface plate 39, but a sheet-like polisher formed into a flat sheet and held in a diaphragm shape may also be used. moreover,
In the above-mentioned apparatus, since the rotary surface plate 37 for rough machining and the rotary surface plate 39 for finishing machining are arranged adjacently,
Although there is an advantage that rough machining and finishing machining can be performed continuously in a single device, it goes without saying that these can be provided separately depending on the case.

Here, as mentioned earlier, it is also possible to perform finishing processing (polishing) immediately without rough processing, and in this case also, the difference in level between the optical fiber 11 and the ceramic ferrule 33 is extremely small. In addition, no scratches or other flaws were observed on the optical fiber 11 portion. It has been confirmed that a high-quality polished surface can be obtained. However, in this case, depending on the amount of protrusion of the optical fiber 11, it goes without saying that the polishing time will be longer than when rough machining is performed.

In the above embodiment, the end face 29 of the ceramic ferrule 33 was previously processed into a convex spherical shape, but the end face may also be polished into a conical shape.

<Effects of the Invention> As described above in detail with reference to examples, according to the present invention, a ceramic ferrule whose end face has been previously processed into a convex curved shape is used, and an optical fiber protruding from the end face is polished. This simplifies the manufacturing process of the optical fiber connector and improves efficiency, and since the end face of the ceramic ferrule functions as a stopper for the progress of processing the optical fiber, there is no difference in level between the optical fiber and the ceramic ferrule. It becomes possible to easily manufacture optical fiber connectors with high precision and high quality.

[Brief explanation of the drawing]

1A to 1C are cross-sectional views of an optical fiber connector in each step of a polishing method according to an embodiment of the present invention, and FIG. 2 is an example of a specific polishing apparatus for carrying out the method of the present invention. Conceptual diagram, 3rd
The figure is a sectional view of the tip of an example of an optical fiber connector processed by the method of the present invention, and Figure 4 is a flowchart showing the conventional manufacturing process of a PC type optical fiber connector.
5A to 5D are cross-sectional views of the optical fiber connector in each step, and FIG. 6 is a conceptual diagram of a conventional spherical surface processing apparatus. In the drawing, 11 is an optical fiber, 19 is an adhesive, and 2
9 is an end face, 31 is an optical fiber insertion hole, 33 is a ceramic ferrule, and 43 is a polisher.

Claims (1)

[Claims] 1 In the method of polishing the end face of a PC type optical fiber connector, the end face of a ceramic ferrule having an optical fiber insertion hole in the center is polished into a convex curved surface in advance, and the optical fiber is inserted into the optical fiber insertion hole of the ceramic ferrule. Then, the optical fiber and the ceramic ferrule are fixed to each other with an adhesive with the end face slightly protruding from the convex curved end face, and then the end face of the ceramic ferrule from which the optical fiber protrudes is polished. The optical fiber is polished by pressing the optical fiber while holding it so that its longitudinal axis is perpendicular to the polisher surface until the end surface of the optical fiber substantially coincides with the position of the convex curved end surface of the ceramic ferrule. How to polish fiber connectors.