JPS63764B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for supporting an optical fiber suitable for supporting an optical fiber held inside a repeater or a connection box.

[Conventional technology]

FIG. 4 is a sectional view showing an example of an optical submarine cable, in which 1 is an optical fiber unit in which a plurality of optical fiber cores 1b are gathered around a central tensile strength line (king wire) 1a, and 2 is the optical fiber unit. 1 is a protective metal pressure layer, 3 is a cable tensile strength member, 4 is a metal tube, and 5 is a plastic insulation layer.

FIG. 5 is a sectional view showing an example of a restraining device for connecting such an optical submarine cable to a repeater.
21 is an anchor disk flange fixed to the anchor disk 20 by a tightening bolt 22; 23 is fixed to the anchor disk 20 by a tightening screw 24. A through hole through which the optical fiber unit 1 passes is provided in the center of the first stay 23. A second stay 25 is fixed to one end of the first stay 23, and is provided with a number of holes through which the optical fiber core 1b and the central tensile strength line 1a are drawn out. A third stay 26 is connected to the second stay 25, and the third stay 26 holds an adjustment nut 29 which is screwed into a caulking sleeve 28 which caulks the central tensile strength line 1a. There is.

The optical fiber core wire 1b is drawn out through a plurality of passages 27, and its remaining length is supported by an elastic support member 30 made of sponge or rubber material, and is inserted into the repeater from the center hole of the curve protector 31. drawn out.

This kind of restraining device was developed by the applicant in a patent application filed earlier.
The application was filed as No. 59-145933, but as seen in this example, the extra length of the optical fiber housed in the tensioning device generally means that a tension above a certain value is applied to the cable. It is pulled into the cable, and when the tension is removed, it returns to almost its original length.

If a small curved portion or a tension concentrated portion is generated in the optical fiber due to a change in the extra length of the optical fiber, the transmission loss of the optical fiber increases or the reliability decreases.

Therefore, it is essential that the optical fiber surplus length holding section has a function of flexibly absorbing changes in the optical fiber surplus length and preventing the occurrence of abnormalities in the optical fiber as described above.

[Problem that the invention seeks to solve]

In order to absorb such changes in the length direction, the supporting elastic body 30 made of sponge or the like is provided in the embodiment shown in FIG. When the optical fiber is drawn in, the elastic body contracts in the radial direction to relieve the tension, but there is a problem in that the relaxation effect decreases as the drawn length increases.

On the other hand, when the retraction is restored, a soft elastic body that sufficiently relieves the tension at the time of retraction will have a weak restoring force, and a block-shaped elastic body will have a long contact length with the optical fiber, so it will return to its original shape. There is a problem in that it becomes difficult to return to the original position, the optical fiber becomes slack, and a small curvature portion occurs.

This invention was made to solve this problem, and the optical fiber is supported by an elastic plate made of thin plastic or rubber material, and the optical fiber can be supported by an elastic plate made of thin plastic or rubber. The present invention provides a method.

[Example] Figures 1a and 1b show a front view and a side view of an elastic support that can be used in the optical fiber support method of the present invention, and 40 is an elastic thin plate made of plastic, rubber, or the like. be. This elastic thin plate 4
0 corresponds to the number of optical fibers to be supported, for example, in the case of six optical fibers, radial arms 41, 41, . , 42... are formed. Note that a through hole 43 may be formed in the center.

FIG. 2a shows a method of supporting an optical fiber by such an elastic thin plate 40. thin plate 4
It is engaged with a guide groove 42 formed on the outer circumferential portion of 0, is supported with an extra length, and is inserted into, for example, a curve protector CP.

Then, even if tension is applied to the cable and the optical fiber core wire 1b is pulled into the retaining part PS of the optical fiber unit as shown by the dotted line, the elastic thin plate 40 is deformed as shown by the dotted line in FIG. 2a. This effectively relieves the tension.

At this time, since the arms 41 supporting the optical fibers of the elastic thin plate 40 are formed radially, even if there is a difference in the amount of pull-in of each optical fiber core 1b, each arm 41 is independently relaxed. It can be effective.

When the tension is removed, an extrusion force acts on the optical fiber core 1b, but at this time, the elastic thin plate 40 returns to its original shape, so the extruded optical fiber core It is possible to prevent the wire 1b from being bent.

According to such an optical fiber support method, even if the extra length section is set to be long, the
As shown in FIG.
By using 0c, there is an effect that correspondence can be achieved.

FIG. 3a is a front view showing another embodiment of the elastic thin plate 40, in which guide grooves 42, 42...
... are formed on the outer periphery of the elastic thin plate 40 formed into a disk shape.

Even in this case, by selecting the thickness and material of the elastic thin plate 40, it is possible to impart an appropriate relaxation effect and restoring force to the optical fiber core wire 1b. Note that openings 44, 44... are provided in the elastic thin plate 40,
The guide grooves 42, 42 may be individually movable. Further, the plurality of elastic thin plates 40 are
As shown in FIG. b, when they are used simultaneously, they may be connected to each other through the through holes 43.

FIG. 3b is a front view showing still another embodiment of the elastic thin plate 40, in which a plurality of guide grooves 42, 42, . . And these guide grooves 42, 42...
is divided by a slit 45 formed in the radial direction, and each guide groove 42, 42, . . . is formed to be easily movable individually.

〔Effect of the invention〕

As explained above, in the optical fiber supporting method of the present invention, the optical fiber is engaged with the guide groove of the elastic thin plate while the optical fiber is spread outward, so even when the optical fiber is stretched or contracted, The optical fiber can be supported flexibly by the deformation of the elastic thin plate and its return force, and in addition, the optical fiber can be supported in a manner that no tension concentration area or small curvature area occurs in the excess length.

[Brief explanation of the drawing]

FIGS. 1a and 1b are front and side views of an elastic thin plate used in the optical fiber support method of the present invention, and FIG.
Figures a and b are explanatory diagrams showing the shape of the elastic thin plate when the optical fiber is drawn in, Figures 3 a and b are front views showing other embodiments of the elastic thin plate, and Figure 4 is an example of an optical submarine cable. FIG. 5 is a cross-sectional view showing an example of a restraining structure for an optical submarine cable. In the figure, 40 is an elastic thin plate, 41 is an arm, 42 is a guide groove, and 43 is a through hole.

Claims (1)

[Claims] 1 A plurality of optical fibers pulled out from a retaining part are anchored in a state in which they are expanded outward by guide grooves formed on the outer periphery of one or more elastic thin plates formed in a circular or radial shape. When the optical fiber is held in a flange and pulled into the retaining portion, the elastic thin plate bends toward the retaining portion to relieve the tension of the optical fiber, and the pulling of the optical fiber is alleviated. 1. A method for supporting an optical fiber, wherein the optical fiber is supported so as to remove slack in the optical fiber by the return force of the elastic thin plate.