JPH0350243B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connection box for submarine optical cables.

Optical communication, which uses optical fiber as a transmission medium, has various advantages such as common band transmission of information, light weight, and noise resistance, so it is an effective means of communication, especially as wired communication between distant points. In recent years, there has been an increasing trend in the use of optical fiber cores.

FIG. 1 is a cross-sectional view of an example of an unarmored submarine optical cable for deep sea use, where 11 is an optical fiber unit in which optical fiber cores are assembled, 12 is a pressure-resistant layer,
13 is a tensile strength wire made of piano wire or the like for adding tensile strength to the cable; 14 is a metal tube layer; and 15 is an insulating layer.

Submarine optical cables with such a structure function as transmission lines connecting remote points, so they are made into long cables with tens to hundreds of connections at the time of shipment from the factory or onboard ships, and then placed on the seabed. It is laid down.

FIG. 2 is a cross-sectional view of a conventional example of a connection structure for a submarine optical cable. The cylindrical casing 17 is mechanically connected to a submarine optical cable (not shown) connected to the detention disk 16 on the opposite side, and the optical fiber The connection part of the unit 11 is connected to the cylindrical housing 17.
It is housed inside.

The connecting portion of the connection container of the submarine optical cable is constituted by a retaining disk 16, a molded portion 18 that molds the retaining disk 16 and the cylindrical casing 17, a boot 19, a taper pin 20, a flange 21, etc. Boots 19 formed on insulating layer 15
is fitted and fixed to the molded part 18 on the uneven surface, and
The submarine optical cable is fixed to the connection container by pressing a tapered pin 20 inserted into a conically expanded space of the tensile strength wire 13 against the retaining disk 16 by means of a flange 21.

However, the connection structure of this type is larger than the conventional connection structure of submarine cables with electric wires as core wires, and the structure is complicated, so the connection work requires skill. It is not suitable for joining light and fragile optical cables.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a submarine optical cable connection box that has a compact connection structure and facilitates connection work.

Hereinafter, the submarine optical cable connection box of the present invention will be explained based on FIG. 3.

In Figure 3 a, b, 11, 12, 13, 1
4 and 15 are the optical fiber unit, pressure-resistant layer, tensile strength wire, metal tube layer of the optical submarine cable described above,
and an insulating layer.

Reference numeral 31 denotes a coated optical fiber separated and exposed from the optical fiber unit 11, and the coated optical fibers 31 to be connected are optically joined by a coated fiber connecting portion 32 approximately at the center. 33 is a slightly thick metal pipe inserted so as to cover the joint portion of the optical fiber core wire 31; 34 has an inner diameter into which the thick metal pipe 33 is inserted;
And as shown in the sectional view taken along line A-A in Figure 3b,
The caulking sleeve 35 is an insulating layer made of synthetic resin that repairs the insulating layer 15 that has been peeled off for connection.

As shown in FIG. 3, the connection method of this invention first splices the optical fiber core wires 31 to be optically bonded to each other by a sleeve method or a gas discharge method, and then attaches a thick wall to the joint. A metal pipe 33 is placed over the metal pipe 33, and a caulking sleeve 34 is further inserted over the metal pipe 33. The caulking sleeve 34 is formed with through holes 34a whose diameter after compression is approximately equal to the outer diameter of the tensile strength members 13 and the same number as the tensile strength members 13. When inserted from the left and right sides and crimped by applying compressive force from the outside of the crimping sleeve 34, the tensile strength wire 13 is deformed together with the through hole 34a due to the crimping, and the two submarine optical cables are separated using the crimping sleeve 34 as an intermediate. tensile strength line 1
3 and 13 will be combined.

Since the tensile force lines 13, 13 oppose the tensile force of the cable, the internal optical fibers are sufficiently protected.

In addition, prior to this caulking work, a hardening agent 36 (thermosetting or natural hardening), which is a mixture of metal powder (for example, aluminum) and adhesive, is applied to the inner surface of the through hole 34a of the caulking sleeve 34 or the surface of the tensile strength wire 13. Applying a layer of adhesive will further strengthen the fixation by caulking.

The connection portion formed in this way is connected to the insulating layer 35.
In order to form the insulating layer 35, the insulating layer 35 is placed in a cylindrical mold, as is well known in injection molding, and is extruded from a synthetic resin.

When connected in the manner described above, the tensile strength wires of the submarine optical cables to be connected are firmly connected to each other by the caulking sleeve 34, and the work is simplified.
This method has the advantage that the finished outer diameter of the connecting portion can be made thinner because it does not use a wire such as 0 or the like. Further, since the thick metal pipe 33 protects the optical fiber 31, there is no risk of damage to the optical fiber 31 including the optical joint.

Also, due to the structure of the caulking sleeve 34, the tensile strength line 1
Since the contact area with the hole 3 is large, a strong bond can be achieved even when caulking is performed with a low compressive force.
If it is applied within the area a, the caulking prevention effect can be further enhanced. Furthermore, caulking sleeve 3
The outer periphery of 4 and the exposed tensile strength wire 13 are integrated by pressing with plastic or the like, and the insulating layer 3
5, it is possible to prevent the tensile strength wire 13 from collapsing, and at the same time, the effect of making the connection part watertight is exhibited. Further, by inserting an O-ring between the pressure layer 12 of the submarine optical cable and the metal pipe 33, watertightness can be further improved.

As explained above, the present invention covers the outer peripheral surface of a metal pipe that protects the connection part of optical fiber core wires with a caulking sleeve, and inserts the tensile strength wires of the cable core into the through holes of the caulking sleeve to compress them. Since the joint is caulked by applying force, it is possible to easily connect submarine optical cables, to reduce the outer diameter of the connecting part, and to simplify the connection configuration. Since the tensioning portion of the tensile strength wire is realized by one caulking sleeve, there is also the effect that the remaining length for connecting the optical fiber is reduced.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a submarine optical cable, Figure 2 is a cross-sectional view showing the connection part of a conventional submarine optical cable, and Figure 3 is a cross-sectional view of a conventional submarine optical cable.
Figures a and b are a cross-sectional view showing a connection box for a submarine optical cable according to the present invention, and a cross-sectional view taken along line A--A. In the figure, 11 is an optical fiber unit, 12 is a pressure-resistant layer, 13 is a tensile strength wire, 14 is a metal tube layer, 1
5 is an insulating layer, 31 is an optical fiber core, 32 is a fiber core connection part, 33 is a thick metal pipe, 34
indicates a crimped sleeve.

Claims (1)

[Claims] 1. The joints of the optical fibers of the submarine optical cables to be connected are inserted into a thick metal pipe, and a plurality of through holes through which the tensile strength wires of the submarine optical cables are inserted are formed in the outer peripheral surface of the metal pipe in the axial direction of the pipe. After fitting the caulking sleeve provided in the through hole and inserting the submarine optical cables into the through hole with the tensile strength wires of the submarine optical cables butting each other, compressive force is applied to the caulking sleeve from the outside to fix the caulking. The submarine optical cable connection box is further characterized in that the outer peripheral surface of the caulking sleeve and the outer surface of the exposed tensile strength wires of the cable are coated with a plastic insulating layer.