JPS6039603A - Construction of sealing part for optical fiber - Google Patents

Abstract

PURPOSE:To prevent peeling owing to shrinkage on curing of an adhesive agent by taking an adhering surface on the direction where the resin adhesive agent shrinks on curing as well as to enable increase in resistance to moisture permeation by sealing at two points on both high and low pressure side. CONSTITUTION:A structure of a sealing part for an optical fiber is provided with a metallic block 13 which is attached to the wall 10 of a case while maintaining airtightness with an O-ring 14, etc. and has a through-hole for insertion of an optical fiber 16 and collars 13a, 13'a in the outlets on both sides of said hole and a core metal 17 which can be inserted together with the optical fiber into the hole of said block 13. The fiber 16 is plced along the metal 17 and is held inserted together with the core metal into the hole of the block 13. A resin adhesive agent 18 is built up in this state on the outside surface of the collars 13a, 13'a at both ends of the hole and the outside circumference of the metal 17. The fiber 16 is embedded into said agent 18 and is thus fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a sealing structure for introducing an optical fiber into a container under high pressure such as an optical submarine repeater.

PRIOR ART AND PROBLEMS fs1 Figure is a diagram for explaining the structure of a conventional optical fiber sealing part, C'a is a cross-sectional view of an optical submarine repeater, and b is a cross-sectional view of the sealing part. In the same figure, 1.1' is an optical cable,
2 is a submarine repeater, 3 is its bulkhead, 4 is an optical fiber, 5-wire optical fiber introduction part, 6 is an amplifier, 7 is a metal block, 8
indicate resin adhesives.

Since the optical submarine repeater 1 shown in Fig. a is installed on the seabed, a very high pressure is applied to the cable 1.1'. Therefore, if the cable is damaged, pressure is applied to the partition wall 3 and seawater attempts to enter the repeater chamber from the optical fiber introduction section 5. In order to prevent this, the optical fiber introduction part 5 is often constructed so that a through hole is made in the metal block 7 as shown in Figure b, the optical fiber 4 is inserted through the hole, and the inside of the hole is sealed with a resin adhesive 8. .

However, in such a sealing structure, stress in the peeling direction occurs on the adhesive interface on the inner surface of the through hole due to shrinkage during resin curing, etc., and even if the initial properties are good, it may deteriorate after a long period of time or due to temperature changes. There is a risk of peeling due to repeated use. In addition, the adhesive resin has permeability to water vapor, so to reduce this it is necessary to lengthen the moisture permeation path and reduce the cross-sectional area of the resin part. It had many drawbacks, such as poor injection workability and incomplete filling, making it difficult to guarantee reliability.

Purpose of the Invention In view of the above-mentioned conventional drawbacks, it is an object of the present invention to provide an optical fiber sealing structure in which there is no fear of peeling of the resin adhesive and the resin part moisture permeable g path is lengthened. be.

According to the present invention, the structure and object of the invention is to provide an optical fiber sealing unit for introducing an original fiber into a device with a pressure difference between the outside and the outside, by penetrating the container wall. A cylindrical metal block through which the Optical 7 Eyeper can be pushed is provided, and the outer peripheral surface of the metal block and the optical fiber inserted through the metal block are connected at two locations on the high-pressure side and low-pressure side of the metal block. This is achieved by providing an optical fiber sealing part t characterized in that it is adhesively fixed with a resin adhesive.

Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a diagram for explaining the structure of the optical fiber sealing part according to the present invention. In the figure, 10 is the wall of the container, 11
is the high pressure side, 12 is the low pressure side, 13 is the metal block, 14 is the 0 ring, 15 is the presser nut, 16 is the light 7 eyeball, 17
18 indicates a core metal, and 18 indicates a resin adhesive, respectively.

This embodiment is a metal plate that is attached to the wall 10 of the container while maintaining airtightness with an O-ring 14, etc., and has a through hole through which the optical fiber is pushed through, and cans 13a and 13'a at both exits of the through hole. A block 13 and a core metal 17 that can be inserted into the through hole of the metal block together with the optical fiber are provided. In this state, resin adhesive 1B is applied on the outer surface of the collars 13a, 13'a at both ends of the through hole and the outer periphery of the core bar 17, and the optical fiber 16 is embedded and fixed in the adhesive. Dechiru.

In this embodiment configured in this way, (1) the adhesive with the metal block for introducing the optical fiber is not on the inner surface of the hole, but on the outer periphery of the metal; and (2) the adhesive surface is set in the direction of curing and shrinkage of the resin. It prevents peeling due to shrinkage and provides airtightness by constantly compressing the adhesive surface.

(2) Also, since the metal block is sealed with a resin adhesive at two locations on the high-pressure side and the low-pressure side, the moisture permeation resistance of the resin portion is increased and airtightness is improved. In this case, higher airtightness can be ensured than on the low pressure side, which is subject to high water pressure.

(2) Note that the resin sealing portions are not limited to two locations, one on the high pressure side and one on the low pressure side, and may connect both.

Effects of the Invention As described in detail above, the optical fiber sealing structure of the present invention prevents peeling due to curing shrinkage of the adhesive by having the adhesive surface in the direction of curing shrinkage of the resin adhesive, and also prevents peeling due to curing shrinkage of the resin adhesive. By sealing at two locations, the side and the low pressure side, the effect of increasing moisture permeation resistance is significant.

[Brief explanation of the drawing]

FIG. 1 is a rounded diagram for explaining the conventional optical fiber sealing structure, and FIG. 2 is a diagram for explaining the optical fiber sealing structure according to the present invention. In the drawings, 10 is the wall of the container. , 11 is a high pressure side, 12 is a low pressure side, 13 is a metal block, 14 is an O ring, 15 is a holding nut, 16 is an optical fiber (, 17 is a core bar, and 18 is a resin adhesive. Patent applicant Fujitsu Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Yukio Uchida Akira Yamaguchi Figure 1 (a) (b) Figure 2

Claims (1)

[Claims] 1. An optical fiber sealing structure for introducing an optical fiber into a container with a pressure difference from the outside, which includes a cylindrical metal block through which the optical fiber can be inserted through the container wall; An optical fiber sealing part characterized in that the outer peripheral surface of the metal block and the optical fiber inserted through the metal block are adhesively fixed at two locations on the high-pressure side and low-pressure side of the metal block using resin adhesive. structure.