JPH05142456A - Tape unit type optical cable and production thereof - Google Patents

Abstract

PURPOSE:To obtain the tape unit type optical cable which does not allow twist strains to remain and the process for production thereof. CONSTITUTION:The process for production of the tape unit type optical cable consisting of plural sheets of tape type optical fibers 4 housed into grooves 3 of a spacer 2 consists in imparting twists to optical fibers 5 at approximately the same pitch as the twist pitch at the time of twisting the fibers to the spacer 2 in the direction opposite from the twist direction thereof to produce the tape type optical fibers 4 at the time of producing the tape type optical fibers 4 or in the stage before this production stage and twisting and housing these tape type optical fibers 4 into the grooves 3 of the spacer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape unit type optical cable in which a tape type optical fiber is housed in a groove of a spacer and a method for manufacturing the same.

[0002]

2. Description of the Related Art A plurality of tape-type optical fibers in which a plurality of optical fiber wires having primary and secondary coatings are arranged side by side in a row in a transverse direction and are collectively covered are housed in a spacer having a spiral groove, and are wound and coated. It becomes a tape unit type optical cable. FIG. 2 shows a cross section of this optical cable 1 and a spacer 2
A tape type optical fiber 4 is housed in the spiral groove 3.
FIG. 3 shows a cross section of the four-core tape type optical fiber 4, which is formed by covering the optical fiber element wire 5 of four cores with a jacket 6.

FIG. 3 shows a tape type optical fiber 4 with a spacer 2
FIG. 3 is a schematic view of the most common take-up rotary type twisting machine, which is a twisting machine when it is accommodated in the spiral groove 3.

The spacer 2 is rotatably fed out from the spacer feeding machine 7, and the plurality of tape type optical fibers 4 supplied from the tape feeding bobbin 9 are fed to the spacer 2 by the gathering die 8.
It is twisted and accommodated along the spiral groove 3, and although not shown in the figure, it is wound up and wound up by the rotary winder 10 that rotates in synchronization with the delivery.

[0005]

At this time, since the tape fiber 4 has a structure in which the tape fiber 4 is laminated in the groove 3, the tape fiber 4 is delivered without being twisted.

Generally, an optical fiber is required to have a small residual strain in view of its life design, and since twisting strain is not given at the time of twisting, the fiber is generally fed with twisting. There is. However, since this tape fiber cable cannot be twisted due to its structure, twist distortion remains.

Quantitatively, this torsional strain ε is

[0008]

[Equation 1]

Where ε: twist strain r: fiber radius a: twisted core radius P: twisted pitch In a normal cable, 1> 4π ² a ² / P ² ,
(1) is ε = 2πr / P (2)

That is, it can be seen that ε is proportional to 1 / P because 2πr is constant. That is, P can be increased to reduce ε. However, if P (pitch) is increased, the characteristics as a cable, for example, the bending characteristics deteriorate.

Therefore, in a normal communication cable, it is customary to adjust the ratio of the pitch to the twisted core diameter, that is, P / 2a to 30 to 50. For example, 2a = 10mmφ, P / 2a
= 40, P = 400 mm. At this time, the twisting strain of the fiber is

[0012]

[Equation 2]

[0013]

This value is a strain that cannot be ignored in terms of fiber transmission characteristics and service life design, and requires sufficient caution during manufacture and construction in order to prevent increase in transmission loss and breakage. It was In particular, in designing the life, the strain remains in the entire length as a twist strain, so that it is necessary to increase the screening level at the time of manufacturing, which is a factor of lowering the fiber yield.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a tape unit type optical cable in which twist distortion does not remain and a method for manufacturing the same.

[0016]

In order to achieve the above object, the present invention provides a tape unit type optical cable in which a plurality of tape type optical fibers are accommodated in a groove of a spacer. In a tape unit type optical cable manufacturing method of a tape unit type optical fiber in which a tape unit type optical cable is provided with a twist and a plurality of tape type optical fibers are accommodated in a groove of a spacer, To produce a tape-type optical fiber by applying a twist in the direction opposite to the twisting direction, which is approximately the same as the twisting pitch at the time of twisting to the spacer, and manufacturing the tape-type optical fiber. It is a method of manufacturing a tape unit type optical cable which is twisted and accommodated in a groove.

[0017]

According to the above construction, by imparting to the optical fiber element wire a twisting strain which is substantially the same as the twisting strain generated at the time of twisting but in the opposite direction, in the tape forming step which is the preceding step or before that, At the time of twisting, the twist distortion is canceled, and thereafter the distortion does not remain.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an example of a tape forming machine for tape type optical fibers according to the present invention.

The optical fiber strands 5 fed from the respective feeding bobbins 11 are made parallel by the assembly die 12, and the molding portion 13 is formed.
The tape-shaped optical fiber 4 is formed into a tape shape by and is wound on the winding bobbin 9.

Each feeding bobbin 11 has a cradle 1
4 is rotatably supported, its cradle 14 is rotatably supported in a direction orthogonal to the bobbin axis, and its rotating shaft 15 is attached with a pulley 16 while the motor 1
7, a drive pulley 18 is connected to these pulleys 16, 1
8 are connected by a chain 19 so that each feeding bobbin 11 can be rotated in the direction of the arrow shown. Further, the optical fiber element wires 5 from the respective feeding bobbins 11 are turned by 90 degrees by the rollers 20 and supplied to the collecting die 12.

In the above, the optical fiber strand 5 from each feeding bobbin 11 is fed to the collecting die 12 by the winding of the winding bobbin 9, and at the same time, the feeding bobbin 11 is rotated by the rotation of the motor 17 so that the feeding bobbin 11 is shown by the arrow in the figure. Is applied to the optical fiber 5 that is rotated and fed out,
In this state, after being formed into the tape type optical fiber 4 by the molding unit 13, the tape type optical fiber 4 is wound on the winding bobbin 9.

The rotation speed of the pay-out bobbin 11 in the twisting direction is one rotation with respect to the running amount of the fiber wire 5 of 400 mm, and the rotation direction is the right direction opposite to the twisting. That is, the tape is formed in a state in which the pitch is the same as that at the time of twisting, but is twisted in the opposite direction beforehand.

The tape-type optical fiber 4 in which the strands 5 are twisted is stored in the groove of the spacer after being twisted by the winding rotary type twisting machine described with reference to FIG. The twisting strain does not remain in the wire.

In the above-mentioned embodiment, a tape type optical fiber in which a strand is twisted is manufactured, and then a payout bobbin wound with the tape type optical fiber is used in a winding rotary type twisting machine. Although the example of manufacturing the optical cable has been described above, the manufacturing of the tape type optical fiber and the manufacturing of the optical cable may be simultaneously performed on the same line.

[0026]

In summary, according to the present invention, since the twisting strain does not remain in the optical fiber strand of the cable, the transmission characteristics (particularly the transmission loss) can be stabilized and the breaking life of the fiber can be extended. Further, since it is not necessary to consider the twist distortion in designing the life of the fiber, the screening level can be lowered accordingly and the yield can be improved.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a tape unit type optical cable.

FIG. 3 is an enlarged cross-sectional view of a tape type optical fiber.

FIG. 4 is a schematic view of a winding rotary type twisting machine for manufacturing a tape unit type optical cable.

[Explanation of symbols]

 1 Tape unit type optical cable 2 Spacer 3 Groove 4 Tape type optical fiber 5 Optical fiber element wire 11 Feeding bobbin 13 Molding part

Claims (2)

[Claims] 1. A tape unit type optical cable in which a plurality of tape type optical fibers are accommodated in a groove of a spacer,
A tape unit type optical cable in which twisting is applied to an optical fiber element of a tape type optical fiber. 2. A method of manufacturing a tape unit type optical cable in which a plurality of tape type optical fibers are accommodated in a groove of a spacer, wherein the optical fiber strand is formed on the optical fiber strand at the time of manufacturing the tape type optical fiber or before the step. A tape-type optical fiber is manufactured by applying a twist in a direction opposite to the twisting direction, which is approximately the same as the twisting pitch at the time of twisting, and the tape-type optical fiber is twisted and accommodated in the groove of the spacer. A method of manufacturing a tape unit type optical cable.