JPS59228618A - Connecting method of optical cable - Google Patents

Abstract

PURPOSE:To connect optical cores easily without the need for an operator and facilities at a photodetection point by returning and connecting adjacent optical cores of two optical cables to be connected together at external terminals (opposite to connection terminal). CONSTITUTION:Optical cores 12A of the optical cables 10A and 10B are inserted into a fusion connecting machine 18, and an LED light source 20 is connected to the external terminal of the optical core 12A of the optical cable 10A to make light incident; and the light passes through the abutting part of the optical cores 12A of the optical cables 10A and 10B and is fed back through the return point 13D of the optical cable 10B. Its light output is inputted to an output meter 22. When those two corresponding optical cores 12A are aligned to each other, the light output has a maximum level, so the fusion connecting machine 18 aligns and connects the optical cores 12A at the optimum abutting position. Similarly, fusion connections are made. Consequently, special return connecting operation is unnecessary and the need for an operator and special facilities at the return point is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for connecting an optical cable consisting of a plurality of optical fibers.

Normally, when connecting optical cables, it is necessary to eliminate minute misalignment caused by eccentricity of the core of the optical fiber and deviation of the outer diameter of the core. In the prior art, fusion splicing devices for connecting optical cables are equipped with precision axis alignment means.

This alignment means converts the optical output of the connection part received at the end of the cable into an electrical signal, feeds back this optical output through a copper wire, and aligns the axis while monitoring this optical output.
The position at which the maximum output is achieved without core axis deviation is detected. The fusion splicer fusion splices the optical fibers at this maximum output position. However, although this connection method can be applied when the optical cable has a copper wire interposed therebetween, in the case of a non-metallic link cable, it is necessary to lay a copper wire at the time of connection. This makes the work difficult or impossible depending on the installation environment. Also.

When connecting, an operator is required to switch and connect the optical core line to the receiving point of the optical cable, and an output meter and modem (optical-electrical interface) are installed at both the receiving point and the connecting point.
The equipment cost was high and it was uneconomical.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical cable connection method that allows optical fibers to be easily connected without requiring a worker or equipment at a light receiving point.

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an optical cable 1 to be connected by the method of the present invention.
0, and this optical cable 10 consists of a plurality of single mode optical core wires 12A to 12F (collectively referred to as 12) twisted around a tensile strength member 11, and an outer sheath 16 is placed on the twisted combination. It is provided. This optical cable 1
0 further includes at least one spare optical fiber 14 twisted together with the single mode optical core 12, and considering the coupling efficiency with the single mode optical fiber 12, this preliminary optical fiber 14 is a multimode optical fiber. It is preferable that Incidentally, as shown in FIG. 2, the tensile strength member 14 may be omitted from this optical cable lo.

Next, a method for connecting optical cables according to the present invention will be explained with reference to FIG. 3. FIG. 3 shows a case where a second optical cable IOB is connected to a first optical cable IOA. As can be seen from FIG. 3, the optical fibers 1 adjacent to each other at the outer end (end opposite to the connection end) of the optical fiber 12 of the first optical cable IOA
2B and 12c, 12D and 12E, and 12F and the spare optical fiber line 14 are connected back at the turning points 13A to 13C, and the outer end of the optical fiber line 12 of the second optical cable IOB (the end opposite to the connection end) Adjacent optical core lines 12A and 12B, 12
c and 12D, and 12E and 12F are connected back at turn points 13D to 13F. Therefore, as shown in the fourth factor, the optical fibers 12A of the optical cables IOA and IOB are inserted into the fusion splicer 18, and the outer end (input end) of the optical fiber 12A of the power end cable IOA is connected to an LED. When the light source 20 is connected and light is input, the output of the light passing through the abutting portion of the optical fibers 12A of the optical cables IOA and IOB is fed back through the turning point 13D of the optical cable 10B. This optical output is input to the fusion splicer 18 via the output meter 22. Therefore, if the corresponding optical fibers 12A of the first and second optical cables are eccentric, the optical output fed back through the turning point 13D will be at a low level, and the fusion splicer 1
The centering means within 8 corrects eccentricity. In this way, 2
When the two corresponding optical fibers 12A are aligned, the optical output has a maximum level and the fusion splicer 18 will align and splice the optical fibers 12A at this optimal butt position. After connecting one optical fiber 12A, the optical cable IOA
Other optical fibers such as 12B and 10B are fusion spliced in a similar manner. In this way, the final optical fiber 12F is connected to the turning point 13C of the optical cable IOA and the preliminary optical fiber 14.
It can be seen that the light output is fed-punctured through the .

Incidentally, for the connection at the turning point, fusion splicing is preferred from the viewpoint of reliability, but groove splicing or other suitable methods may also be used.

Figure 5 shows three optical cables IOA and IOB.

Indicates the case where 10G corresponding optical fiber lines are connected at the same time,
In this case, folding points 13A to 13F similar to the folding points 13A to 13F at the outer ends of the first and second optical cables in the embodiment of FIG. 13F, no turning point is formed in the intermediate optical cable IOH, and the optical core wires of this intermediate optical cable IOB are matched with the corresponding optical core wires of the optical cables IOA and 10C on both sides. Therefore, when connecting the optical fibers 12A of these optical cables, the monitor light is connected to the optical fiber 12A.
It passes through the abutting point, is turned back at the turning point 130, and is fed back to each connection portion through the optical core wire 12B of the optical cables IOC and IOB.

In the above embodiment, the toe core wire 12 is a single mode optical core wire, but the toe core wire 12 is not limited to a single mode optical core wire, but may be a multimode optical core wire.

According to the present invention, as described above, since the optical cable is provided in advance with a turning point for feedback during fusion splicing, there is no need for special turning connection work, and the operator and special It is economical because it does not require any equipment.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of different examples of optical cables used in the method of the present invention, FIG. 3 is a schematic diagram of the optical cable connection method of the present invention, and FIG. 4 is a schematic diagram of the main parts of the present invention. Explanatory diagram,
FIG. 5 is a schematic diagram of another embodiment of the invention. 10, IOA to 10C --- optical cable, 12,
12A to 12F---m=multiple tip lines, 13A to 13F---turning point. 14-----One-piece core wire, 18--Fusion splicer, 20--m-Output meter.

Claims (3)

[Claims] (1) The optical outputs passing through the abutting portions of the corresponding optical fibers to be connected in a plurality of optical cables consisting of a plurality of optical fibers are fed back, and the above-mentioned action is taken at the optimal butting position when the optical output level is the maximum. In an optical cable connection method in which optical fibers to be connected are sequentially fused and spliced, adjacent optical fibers are folded back and connected at the outer ends of a plurality of optical fibers in the outermost optical cable, and the butt portion of the optical fibers to be connected is 1. A connecting force method for an optical cable, characterized in that the optimum abutting position is detected by feeding back light passing through the abutting portion to the abutting portion via an adjacent optical core line. (2) The optical cable includes at least one spare toe core wire, and the final optical core wire detects the optimal abutting position based on the optical output fed back through the preliminary toe core wire. A method for connecting an optical cable according to paragraph 1. (3) The optical cable connection method according to claim 1 or 2, wherein the spare lead wire is a multimode optical core wire.