JPS59116029A - Method for detecting disconnection during reinforcing connection part of optical fiber - Google Patents

Abstract

PURPOSE:To detect exactly and rapidly the disconnection of an optical fiber by setting together plural fiber cores to a photodetector. CONSTITUTION:Light is made incident to each fiber 8 separated from a light source end 13 of optical fiber core wires 6, 6'. Each fiber core 8 of the wires 6, 6' is connected together by melting at the connection point 10. Then both ends of a reinforcing tube 3 inserted previously to the part 10 are converted to the covers of the wires 6, 6', the light is made incident from a light source 9 to each fiber core 8, the core 8 is bundled at a distant end 11 of the wire 6 and set to the photodetector 12, and the total light output of each core 8 is measured. After the measurement, the tube 3 is heated to reinforce the part 10, and the total light output is measured again. The wire disconnection is detected from the light output ratio before and after this reinforcing treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for detecting optical fiber breakage when reinforcing optical fibers after multi-fiber fusion splicing.

[Background technology]

In order to make optical fiber cables more economical and smaller in diameter, a tape-shaped high-density optical fiber core 6 as shown in FIG. 1 has been developed and is now in the stage of practical use.

Therefore, it is necessary to connect all at once due to the cable structure.Currently, various studies are being carried out on this all-in-one fusion splicing and all-in-one reinforcing method, but the biggest problem is when reinforcing the connection part. Second, there is a method for detecting disconnection when an optical fiber is disconnected.

An example of a conventional method for reinforcing single-core optical fibers after fusion splicing will be explained with reference to FIG. A reinforcing tube 3, which shrinks when heated, is placed over the bare fiber portion 2, which has been fused and spliced after removing the secondary coating 1, so as to overlap with the secondary coating 1 on both sides, and then the reinforcing tube 3 is heated. to strengthen the connection. In this case, a certain tension is applied to the optical fiber line 5 before or during the reinforcement. Therefore, if a breakage occurs in the bare fiber core wire 2 before reinforcement, that is, before covering and heating the reinforcing tube 3, or during reinforcement, that is, heating the reinforcing tube 3, it is possible to detect all the breaks immediately. Can be done.

However, when performing bulk fusion splicing 7f as shown in FIG. 3 with tape-shaped high-density optical fiber core wire 6 as shown in FIG. For example, even if one of the five cores breaks before or during reinforcement, it cannot be detected. Of course, there is no problem if it can be confirmed visually from the outside of the reinforcing tube 3, but even if a transparent reinforcing tube is used, the presence or absence of a disconnection cannot be determined by this visual inspection. Further, as shown in FIG. 4, a light source 9 is coupled to each fiber core 8 to allow light to enter therein, and the optical output of each optical fiber core 8 is measured at the far end 11 of the connection point 10 to detect a disconnection. There is a method, but this method involves processing the ends of the optical fibers 6, that is, removing a long secondary coating 1 from the optical fibers 6, and setting each fiber core 8 one by one into the receiver 12. It is time consuming and highly inefficient.

[Disclosure of the invention]

Therefore, in order to eliminate the above-mentioned problems, the present invention, when reinforcing a joint of an optical fiber, receives the light transmitted to a plurality of optical fibers at once at the far end of the joint before and after the reinforcement, The purpose of this invention is to detect a break in a fiber from the optical output ratio before and after reinforcement, and to provide a very simple, yet accurate and quick method of detecting the presence or absence of a break in a connection.

The present invention will be explained in detail below with reference to FIG.

As shown in the figure, a light sound is made incident on each separated fiber core 8 from the light source end 13 of the two optical fiber cores 6, 6'. At the connection point 10, the fiber cores 8 of the optical fiber cores 6, 6' are collectively fused and spliced as shown in FIG. After that, the reinforcing tube 3 that was inserted into this connection part
Both ends of the fiber cores 6 and 6' are covered with an oat wrap, and light is incident on each fiber core 8 from a light source 9.
At the far end 11 of the optical fiber core 6, the fiber cores 8 are set together in a light receiver 12 without separating them one by one, and the total optical output of each fiber core 8 is measured.

After completing this measurement, as already explained, the reinforcing tube, which shrinks when heated, is heated to reinforce the connection part, and after the reinforcement due to this shrinkage is completed, each fiber core is again Measure the total light output and determine the light output ratio before and after reinforcement treatment. Then, a disconnection is detected from this optical output ratio. In this case, if, for example, one of the five fibers of the fiber breaks during reinforcement, the optical output ratio before and after reinforcement will be about 3, so the breakage can be easily detected.

[action, effect]

As explained above, according to the method of the present invention, the fiber cores 8 are loaded onto the receiver 12 all at once. ,
Since only one light receiver 12 is required, it is possible to save time and equipment, and the effect is particularly significant in multi-core cables with several hundred fibers.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a tape-shaped optical fiber core. FIG. 2 is an explanatory diagram of reinforcement. FIG. 3 is an explanatory diagram of batch fusion splicing. FIG. 4 is an explanatory diagram of a conventional optical output measuring method. FIG. 5 is an explanatory diagram of the implementation of the present invention. 1... Secondary coating, 2... Bare fiber, 3... Reinforcement tube, 4... Overlap, 5... Single fiber core wire, 6.6'... Tape type optical fiber Core wire, 7.
...Fusion splicing, 8...Fiber core, 9...Light source, 1
0... Connection point, 11... Far end, 12... Light receiver, 1
3...Light source end.

Claims (1)

[Claims] (1) When reinforcing an optical fiber connection, the light transmitted to multiple optical fibers is received all at once at the far end of the connection before and after the reinforcement; optical fiber breakage is detected based on the optical output ratio before and after reinforcement. A method for detecting disconnection when reinforcing an optical fiber connection, characterized by detecting.