JPH02216107A - Method for fixing terminal of optical fiber - Google Patents

Abstract

PURPOSE:To surely prevent the crack and rupture of a fiber by a difference in thermal expansion by injecting the gel of silica glass into an optical fiber holding member and subjecting the gel to dehydration condensation to vitrify the gel, thereby fixing the holding member and the fiber. CONSTITUTION:The gel 8a of the silica glass 8 of a low viscosity is injected into the hollow hole 6a of the optical fiber holding member 6 and the optical fiber 7 and a capillary 9 are inserted in the directions of arrows A, B from the left side and the right side. The gel 8a is subjected to the dehydration condensation to vitrify. The optical fiber holding member 6, the optical fiber 7 and the capillary 9 are eventually fixed by the silica glass 8 having the coefft. of expansion equal to the coefft. of expansion of the fiber 7 or approximate thereto. The crack and failure of the optical fiber 7 arising from the difference in the coefft. of expansion by a temp. change is, therefore, prevented surely.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to optical connectors and terminals for optical modules used in optical communications, and particularly to optical fiber holding members that are parts of optical connectors and terminals for optical modules. The present invention relates to a method of fixing the optical fiber to the bare optical fiber.

[Conventional technology]

Conventionally, this type of optical fiber terminal fixing method involves fixing an optical fiber 4 and an optical fiber holding member 1 via an adhesive 3 filled in a hollow hole 2 of an optical fiber holding member 1, as shown in FIG. Capillary 5 was fixed with adhesive.

[Problem to be solved by the invention]

However, in the above-described conventional optical fiber terminal fixing method, after the adhesive 3 has hardened, the optical fiber strand may be damaged due to temperature changes due to the difference in expansion coefficient between the adhesive 3 and the optical fiber strand 4. There is a drawback that stress is applied to the optical fiber 4 and the optical fiber 4 is likely to crack or break.

An object of the present invention was made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide an optical fiber terminal fixing method that can prevent cracks and breakage of optical fiber strands caused by differences in expansion coefficient due to temperature changes.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a method for fixing a hollow cylindrical optical fiber holding member constituting an optical fiber terminal member and an optical fiber strand inserted into this optical fiber holding member. After a silica-based glass gel is injected into the fiber holding member, the gel is dehydrated and condensed and vitrified to fix the optical fiber holding member and the optical fiber strand.

[Effect]

In this way, in the method of the present invention, the optical fiber holding member, the optical fiber strand, and the capillary are fixed with silica-based glass whose expansion coefficient is equal to or close to that of the optical fiber strand. It is possible to prevent cracks and breaks in the optical fiber that would otherwise occur due to differences in expansion coefficients.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Fig. 1 is a vertical cross-sectional view of an optical fiber terminal structure employing the fixing method of the present invention, and Figs. 2 (A>, (B) are assembly explanatory diagrams of the fixing method of the present invention. The hollow hole 6a of this optical fiber holding member 6 is filled with silica-based glass 8 whose expansion coefficient is equal to or close to that of the optical fiber strand 7. The optical fiber wire 7 and the capillary 9 are inserted and fixed in the hollow hole 6a.The hollow hole 6a is formed of a large diameter hole 6b and a small diameter hole 6C, and the large diameter hole 6b is filled with nylon. A capillary 9 is arranged on the right end side of the small diameter hole 6c where the core wire 10 is arranged.

Now, to explain the method of fixing the optical fiber inside the optical fiber terminal, first, as shown in FIG. After that, the optical fiber 7 and capillary 9 are inserted into the hollow hole 6a from the left and right sides as shown by arrows A and B, respectively. Then, this gel 8a is dehydrated and condensed, vitrified, and this silica-based glass 8
The optical fiber wire 7 and the capillary 9 are fixed in the hollow hole 6a of the optical fiber holding member 6 (see FIG. 2(B)). Further, even if this gel 8a is left at room temperature, vitrification due to dehydration condensation will proceed, but if treatment such as heating is applied, the reaction will proceed more quickly. In addition, the chemical formula of the gel 8a of the silica-based glass 8 and the chemical formula of the silica-based glass 8 are shown in FIG.

Further, the method for preparing the gel 8a of the silica-based glass 8 and the method for rapidly proceeding with the dehydration condensation are disclosed in the following documents.

(i) Treat on Mate
Rials 5science and Techno
logy, VQI, 22. Academic P
ress, (ii) Sumio 5akka, 1
9g2. PP 129-167, (How to make gel), (iii) 11. S, Pat, No, 4,76
7.429 (How to make gel), (iv) U, S, P
at, No, 4,477.580 (How to make gel +
dehydration condensation), (V) U, S, Pat, No, 3.9
54431 (How to make gel + dehydration condensation) (■) Mouth,
S.

Pat, No. 4,419,115 (How to make gel +
dehydration condensation) [Effects of the Invention] As explained above, according to the optical fiber terminal fixing method according to the present invention, an optical fiber holding member, an optical fiber strand,
By fixing the capillary with silica-based glass whose expansion coefficient is equal to or close to that of the optical fiber, cracks and breakage of the optical fiber, which conventionally occur due to differences in expansion coefficient due to temperature changes, can be avoided. This has the effect of reliably preventing this.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of an optical fiber terminal structure employing the fixing method of the present invention, Figs. 2 (A) and (B) are assembly explanatory diagrams of the fixing method of the present invention, and Fig. 3 is a silica-based glass gel. FIG. 4, which is a diagram showing the chemical formula of silica-based glass, is a longitudinal sectional view of an optical fiber terminal structure employing a conventional fixing method. 6... Optical fiber holding member, 6a...
Hollow hole, 7... Optical fiber wire, 8... Silica glass, 8a... Gel, 9... Capillary. Applicant NEC Co., Ltd. Agent Patent attorney Atsushi Yamauchi Umeo 20 (A) (B) Figure 3

Claims (1)

[Claims] In a method for fixing a hollow cylindrical optical fiber holding member constituting an optical fiber terminal member and an optical fiber strand inserted into this optical fiber holding member, silica-based glass gel is injected into the optical fiber holding member. After that, the gel is dehydrated and condensed and vitrified to fix the optical fiber holding member and the optical fiber strand.