JP2000105326A - Ferrule for optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an optical fiber from being damaged when inserting an optical fiber by arranging a small tapered part between a ferrule pore and a guide hole. SOLUTION: This is a ferrule having a pore 6 for inserting and fixing an optical fiber in the center. Here, a tapered guide hole 3 communicating with the pore 6 is formed at one end part, and a small tapered part 5 having an angle larger than 0 deg. and not exceeding 5 deg. is formed on the boundary part between the guide hole 3 and the pore 6, and further a curved surface part 4 is formed on the boundary part between the small tapered part 5 and the guide hole 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical fiber ferrule for holding an end of an optical fiber.

[0002]

2. Description of the Related Art In recent years, information transmission by optical signals using optical fibers has been widely performed. At this time, an optical connector is used to connect the optical fibers. An optical fiber ferrule is used for the optical connector. The ferrule is formed with a fine hole for inserting and fixing the optical fiber and a guide port for facilitating insertion of the optical fiber.

[0003] The boundary between the above-mentioned pore and the above-mentioned guide port is a place where stress on the optical fiber is concentrated and needs to be connected smoothly. Therefore, as shown in FIG. A curved surface portion 4 is formed so that the boundary between the tapered guide port 3 formed on one end surface 2 and the fine hole 6 is connected by a smooth curved surface.

The ferrule 1 is made of a ceramic such as zirconia, and the pores 6, the guide port 3 and the curved surface 4 are formed at the time of molding. Further, after forming, the pores 6 are processed to have a desired size.

[0005]

However, as described above, since the pores 6 are processed into desired dimensions after molding, the curved surface portions 4 formed at the time of molding are shaved, and the pores 6 and the guide holes 3 are formed. There is a disadvantage that an edge is generated at the boundary.

There is a problem that the edge scratches the optical fiber when the optical fiber is inserted or after the optical fiber is fixed, which adversely affects the reliability when the optical fiber is inserted and after the optical fiber is fixed.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an optical fiber ferrule having a fine taper portion having a taper angle of 5 ° or less at a boundary between the fine hole and the curved surface portion. The curved surface portion was not shaved even when processing was performed, and the adverse effect on the optical fiber was eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of an optical fiber ferrule 1.
2 shows an enlarged view of the vicinity of the guide opening 3. Ferrule 1
A tapered guide port 3 having a taper angle β is formed on the side of the end face 2. A curved surface portion 4 is formed continuously from the guide opening 3. A minute taper portion 5 having a minute taper angle α is formed continuously from the curved surface portion 4.
The pores 6 are formed continuously.

Then, the tip of an optical fiber (not shown) is inserted from the guide port 3 side and fixed with an adhesive or the like. At this time, the optical fiber is smoothly inserted by the guide port 3 and the curved surface 4. it can.

In the method of manufacturing the ferrule 1, a ferrule 1 as shown in FIGS. 1 and 2 is first formed using a predetermined raw material, and then the pores 6 are expanded by processing to obtain a desired size.
At this time, due to the presence of the tapered portion 5, the curved surface portion 4 is not processed, and the space between the fine hole 6 and the tapered portion 5 is smoothly continued with the small taper angle α.

The taper angle α of the small taper portion 5 is 0 °
It is desirable that the angle be larger than 5 °. This is because if the taper angle α is 0 °, the above-described effects cannot be obtained, while if it exceeds 5 °, an edge is likely to be formed at the boundary between the tapered portion 5 and the pores 6. Further, it is desirable that the length L of the minute tapered portion 5 is 0.2 to 3 mm. This is because if it is out of this range, it is difficult to obtain the above-described effects.

Further, the radius of curvature R of the curved surface portion 4 is 0.0
It is desirable that it is 5 to 2.05 mm. Guideway 3
Is usually 30 to 45 °.

The material of the ferrule 1 can be zirconia, alumina, other ceramics, glass, plastic, resin, or the like. As a molding method, injection molding, injection compression molding, press molding, and transfer molding can be considered.

[0015]

Here, as an embodiment of the present invention, as shown in FIG. 3, the taper angle α of the minute taper portion 5 is 2 °, its length L is 0.75 mm, and the initial inner diameter of the pore 6 is φ0.1m
m, the radius of curvature R of the curved surface portion 4 is 1.8 mm, the taper angle β of the guide port 3 is 30 °, and the inner diameter of the pore 6 is φ0.126 m.
m.

In this case, as shown in FIG. 3, it can be seen that even after processing, the contact point between the pore 6 and the fine taper portion 5 has an angle of 2 ° and is almost smoothly connected.

On the other hand, as a comparative example, as shown in FIG.
When the other conditions are the same as in FIG. 3 without the minute taper portion 5, when the inner diameter of the pore 6 is expanded to 0.126 mm by processing, the boundary 7 between the pore 6 and the curved surface portion 6 becomes 6.89.
Therefore, the optical fiber has a low degree of reliability, such as being damaged when the optical fiber is inserted.

Next, Table 1 shows the results of a test on the effect of the taper angle α of the minute taper portion 5 on the optical fiber. The test method is as follows. A taper angle α of the minute taper portion 5 is set at 0 ° to 8 ° in increments of 1 °, and 100 samples are prepared. After inserting and bonding the optical fiber, a heat cycle test (−40 to +
(75 °, 500 cycles), and the number of fiber breaks thereafter was investigated.

From these results, it can be seen that the taper angle α of the minute taper portion 5 should be larger than 0 ° and 5 ° or less.

[0020]

[Table 1]

Next, Table 2 shows the results of investigation on the radius of curvature R of the curved surface portion 4 and the hooking at the time of fiber insertion.
The test method is such that the radius of curvature R of the curved surface portion 4 is 0.02 mm or more.
100 samples were prepared in steps of 0.02 mm up to 0.18 mm, and the number of those that were caught when inserting an optical fiber was investigated.

From this result, the radius of curvature R is 0.05 mm
It is desirable to make the above. Further, the maximum value of the radius of curvature is when the curved surface portion 4 and the taper of the guide port 3 are in contact at the end face, and when the diameter of the guide port 3 is φ1.2 mm and the taper angle β of the guide port 3 is 45 °, As shown in FIG. 5, it is 2.05 mm.

To summarize the above, the radius of curvature R of the curved surface portion 4
It can be seen that the thickness should be 0.05 to 2.05 mm.

[0024]

[Table 2]

[0025]

As described above, according to the present invention, by providing a minute taper portion between the fine hole of the ferrule and the guide port,
It is possible to prevent the occurrence of scratches or the like at the time of inserting the optical fiber and improve the reliability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical fiber ferrule of the present invention.

FIG. 2 is an enlarged sectional view of the vicinity of a guide port of the ferrule for an optical fiber of the present invention.

FIG. 3 is a comparison diagram of a ferrule for an optical fiber according to the present invention before and after processing near a guide opening.

FIG. 4 is a comparison diagram of a conventional optical fiber ferrule before and after processing near a guide opening.

FIG. 5 is a diagram for examining a maximum radius of curvature of a curved surface portion of an optical fiber ferrule.

FIG. 6 is a cross-sectional view of a conventional optical fiber ferrule.

[Explanation of symbols]

 1. Ferrule 2. End face 3. Guideway 4. Curved surface 5. Micro taper part 6. pore

Claims (2)

[Claims] 1. A ferrule having a hole at the center for inserting and fixing an optical fiber, wherein a tapered guide port communicating with the hole is formed at one end, and the guide port is connected to the fine port. A minute taper portion having a taper angle larger than 0 ° and 5 ° or less is formed at a boundary portion with the hole, and a curved surface portion is formed at a boundary portion between the minute taper portion and the guide port. Ferrule for optical fiber. 2. A curvature radius of the curved portion is 0.05 to 2.0.
An optical fiber ferrule having a length of 5 mm.