JPS63143514A - Optical cable connecting method for electric power and optical composite cable - Google Patents

Abstract

PURPOSE:To make handling advantageous by connecting optical fiber cores of connection parts without any extra length, cutting them by specific length if the connection is a failure and interposing an intervenient core of corresponding length for reconnection, and equalizing the connection part and a cable in outer-diameter to each other. CONSTITUTION:Exposed end parts of optical fiber cores 1A and 1B to be connected are welded at a connection part 2. If the connection is a failure, parts I and I are cut, the intervenient core corresponding to the removal length is interposed, and connections are made again at connection parts 4A and 4B. If the connections are further a failure, parts II and II are cut, intervenient cores 5 of corresponding length are interposed, and connections are made again at connection parts 6A and 6B. This operation is repeated until successful connections are made, and a connection having no extra length can be made by up to three-time connecting operation. The part between metallic sheets 8 of core bundles 7 are sheathed with a connection protection pipe 9. Thus the connection part and cables are equalized in outer diameter and the cables are laid advantageously in a device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for connecting optical cables housed in a power/optical composite cable.

[Prior art and its problems]

Figure 3 shows an example of a conventional submarine power/optical composite cable. #11 is three electric cable cores, 12 is an optical cable,
13 is an interposition, 14 is a pressure tape winding, 15 is a tensilan member, and 16 is an exterior sheath. As shown in the figure, the optical cable 12 is thinner than the electrical cable cores 11, and therefore is usually disposed in a groove, so-called shoulder, between adjacent electrical cable cores 11.

By the way, due to the length of such submarine power/optical composite cables, it is necessary to provide a connection part for the electric cable core and a connection part for the optical cable in the middle, but in the case of such cables, each connection It is desirable that the outer diameter of the composite cable be approximately the same as the outer diameter of the power cable core or the optical cable so that the outer diameter of the composite cable as a whole does not change in the longitudinal direction.

Same-diameter connection of electric cable cores has been done for a long time.
Although it is not particularly difficult, when connecting optical cables, it is necessary to provide extra length at the connection part in order to redo the connection in the event of a mistake in connecting the optical fibers. Therefore, the outer diameter of the connection part becomes considerably larger than the outer diameter of the optical cable.As a result, the outer diameter of the composite cable in the part that contains the optical cable connection part becomes locally large, which only makes the installation work more troublesome. This causes problems such as the part containing the optical cable connection part becomes a mechanical weak point and is easily damaged.

[Means for solving problems and their effects]

In order to solve the problems of the prior art as described above, the present invention provides a method for connecting optical cables in a power/optical composite cable, in which the sheath at the end of the optical cable to be connected is stripped to expose the optical fiber core wire. and connect the corresponding optical fibers with no extra length necessary for reconnection in the event of a connection failure, and if the connection fails, cut the optical fibers including the spliced part to a specified length. In the meantime, insert a split optical fiber core corresponding to the removed length,
Both ends of the optical fiber are connected to the above-mentioned optical fiber, and if the connection fails, the optical fiber including both connections is cut to a predetermined length and removed. Insert the split optical fiber,
Repeat this process of connecting both ends of the optical fibers to the optical fibers, respectively, until the connection is successful, and after connecting the optical fibers in this way without excess length, connect the optical fibers between the sheaths of the optical cables. It is characterized by being covered with a protective tube.

In this way, there is no need to provide an extra length for the optical fiber core at the connection section for reconnection in the event of a connection failure, so the outer diameter of the optical cable connection section can be reduced, and the optical fiber It is possible to make the diameter almost the same as the outer diameter.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

Optical cables housed in power/optical composite cables generally have a structure in which a required number of optical fiber cores and tensitane members are housed within a metal sheath made of aluminum or the like.

The metal sheath may also be filled with sherry or the like.

When connecting such optical cables, the metal sheaths at the ends of both optical cables are first peeled off to expose the optical fibers.Then, the corresponding optical fibers are connected. The connections are made as shown in FIG.

That is, first, as shown in (al), the optical fiber core wires IA-IB to be spliced are fusion-spliced by butting their ends together without any extra length necessary for re-splicing in the event of a splicing failure. This is the termination connection section.If a good connection state is obtained in this connection, the connection of the optical fiber cores IA and IB is completed.

If 1. If a good connection cannot be obtained with this connection, connect the optical fiber cores IA and IB including the connection part 2!・Cut at point I and remove.

Next, as shown in (bl), a split optical fiber core 3 corresponding to the removed length is inserted between the ends of the optical fiber cores IA and IB, and both ends of the optical fiber core wire 3 are inserted between the ends of the optical fiber cores IA and IB.
Fusion splice each to B. 4A and 4B are the fusion spliced parts. If a good connection state is obtained with this connection, the connection of the optical fiber cores &il IA/IB is then completed.

If a good connection condition cannot be obtained even with this connection, connect the optical fiber core IA including the connection parts 4A and 4B.
・Cut IB at ■・H and remove it from the 0th order (C
As shown in 1, between the ends of the optical fiber core wires IA-IB,
A split optical fiber core 5 corresponding to the removed length is inserted, and both ends thereof are fusion-spliced to the optical fiber cores LA and IB, respectively. 6A and 6B are the fusion splicing parts. If a good connection state is obtained through this connection, the connection of the optical fiber cores IA and IB is then completed.

If this connection also fails, repeat the connection process as described above until the connection is successful.The probability that the connection will fail is about 30% at most, so it is better to connect successfully in one attempt. In most cases, if you reconnect one optical fiber at most three times, the connection will most likely be successful. That's how you connect.

After the connection of each optical fiber core wire is completed, as shown in Fig. 2, a connecting protection tube 9 made of the same material is placed between the metal sheaths 8A and 8B of the optical cables 7A and 7B, and both ends of the tube are soldered. Seal. In FIG. 2, II to 1. is the connected optical fiber core wire, 2, 4A, 4B, 6A, 6B
is a fusion splice, and in this example, the optical fiber core 11
is the second connection, 1□ is the first connection, 1. indicates the third connection, and 1#.1 indicates the first connection, and each indicates a successful connection. Note that the connection protection tube 9 is filled with sherry or the like as required.

By the way, in the connection method of the present invention, the number of connection parts of the optical fiber core increases, which may increase transmission loss, for example, 0.5
When configuring a 50 km line with dB/Km optical fiber cores, if one connection is required every 10 km due to constraints such as manufacturing equipment, there will be 4 connection points, all of which will be connected at the first time. Loss in case of success is 25.4dB
On the other hand, if all connections are successful from the second time onwards, the loss will be 25.8 dB.

In other words, the difference is at most 0.4 dB, and an increase in loss due to an increase in the number of connections is hardly a problem.

〔Effect of the invention〕

As explained above, according to the present invention, optical fiber cores can be connected without extra length, so the outer diameter of the optical cable connecting portion can be made equal to the outer diameter of the optical cable.

Therefore, the outer diameter of the power/optical composite cable does not increase in the portion containing the optical cable connection portion, and there is an advantage that installation is easy and the power/optical composite cable can be constructed without mechanical weaknesses.

[Brief explanation of the drawing]

FIG. 1 (al to tc+ is an explanatory diagram showing a method of connecting optical fiber core wires in an optical cable connection method according to an embodiment of the present invention, and FIG. 2 shows an optical cable connection section obtained by the same connection method. The vertical cross-sectional view and Figure 3 are cross-sectional views of the submarine power/optical composite cable.
6B - Optical fiber core wire connection section, 3.5 - Split optical fiber core wire, 7A.7B - Optical cable, 8A.8B - Metal sheath, 9 - Connection section protection tube. Figure 1 Figure 2 Figure 3 1j 14

Claims (1)

[Claims] In the method of connecting optical cables in power/optical composite cables, the sheaths at the ends of the optical cables to be connected are stripped to expose the optical fiber cores, and the corresponding optical fiber cores are connected as required for reconnection in the event of a connection failure. Connect with no excess length,
If the connection fails, cut the optical fiber containing the spliced part to a specified length and remove it. In the meantime, insert a split optical fiber corresponding to the removed length and connect both ends. When the optical fibers are connected to each of the above optical fibers, and the connection fails, the optical fibers including both connections are cut to a predetermined length and removed, and during that time, a cut is made corresponding to the removed length. Insert the optical fiber and connect both ends to the above-mentioned optical fiber, repeating this until the connection is successful, and after connecting the optical fiber in this way without excess length. , A method for connecting an optical cable in a power/optical composite cable, characterized in that a connection protection tube is placed between the sheaths of the optical cable.