JP2000171672A - Optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable having excellent bending tension characteristics in a structure for housing coated optical fiber ribbons 4 into a pipe. SOLUTION: Intervening tapes 3a and 3b are arranged on both sides of the laminated coated optical fiber ribbons 4 when the coated optical fiber ribbons 4 are laminated and housed into the aluminum pipe 2, by which buffer layers to compressive force from the plane in the thickness direction of the ribbons are obtained and the bending tension characteristic is improved. The buffer effect to respective layers of the coated optical fiber ribbons 4 may be expected by setting the height of the intervening tapes 3a and 3b to be arranged equal to or higher than the lamination height of the coated optical fiber ribbons 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical fiber cable.

[0002]

2. Description of the Related Art A conventional optical fiber cable is mainly of a so-called tape spacer type in which tape cores are laminated and housed in a groove of a spacer made of polyethylene or the like. The structure of this type of optical fiber cable is small in diameter, light in weight, and has excellent performance.

[0003]

However, in order to meet the recent demand for cost reduction, a simpler structure is required, and this structure is inferior in that respect.

In the conventional optical fiber cable, since the optical fiber ribbon is laminated in the groove of the spacer, it is necessary to manufacture the spacer in advance.

[0005] Furthermore, the process of accommodating the tape core wire in the spacer groove and the sheathing process are inconvenient in terms of lowering the cost because tandem manufacturing is difficult.

In the tandem manufacturing of the step of housing the tape core and the step of sheathing, a structure in which the tape core is stacked and housed in a pipe or the like without using a spacer or the like is desirable. When such a force is applied, a compressive force is applied to the surface in the thickness direction of the tape core wire, which may cause an increase in loss.

[0007] In particular, the air core type in which the waterproof mixture such as jelly is not filled in the pipe has a problem that the tendency is strong.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide an optical fiber cable having a structure in which an optical fiber ribbon is accommodated in a pipe and having excellent bending and tensile characteristics.

[0009]

In order to achieve the above object, an optical fiber cable according to the present invention comprises a plurality of optical fiber ribbons laminated and housed in a pipe. Interposition is arranged on both sides of the cord.

In addition to the above configuration, the optical fiber cable of the present invention is preferably such that a plurality of optical fiber ribbons are laminated, twisted at a predetermined pitch, and stored in a pipe.

In addition to the above configuration, the optical fiber cable of the present invention is preferably provided with a cushion layer in the gap between the pipe and the optical fiber ribbon.

In addition to the above configuration, in the optical fiber cable of the present invention, the height of the interposition is preferably equal to or more than the lamination height of the optical fiber ribbon.

[0013] In addition to the above configuration, in the optical fiber cable of the present invention, the material of the pipe is preferably plastic or metal.

According to the present invention, when the optical fiber ribbons are stacked and housed in the pipe, the interposition is disposed on both sides of the laminated optical fiber ribbons, so that the interposition is made from the surface in the tape thickness direction. It serves as a buffer layer against compressive force and improves bending and tensile properties. By setting the height of the interposition to be equal to or more than the lamination height of the optical fiber ribbon, a buffering effect can be expected for the optical fiber ribbon of each layer.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the optical fiber cable of the present invention.

The optical fiber cable shown in FIG. 1 includes a plurality of (but not limited to, six in the figure) laminated optical fiber ribbons 4 and a laminated optical fiber ribbon 4.
(Interposition tape) 3a, 3b arranged on both sides of
A holding tape 5 wound around the outer periphery of the optical fiber tape 4 and the intervening tapes 3a and 3b, an aluminum pipe 2 in which a tape unit in which the optical fiber tape 4 is laminated, and an outer periphery of the aluminum pipe 2 Provided PE sheath 1
It is composed of

The optical fiber cable in which the optical fiber tape cores 4 are stacked and housed in the aluminum pipe 2 is subjected to bending or tensile force during laying, construction or actual use.
In this case, depending on the bending direction, a state occurs in which the individual optical fiber tape cores 4 are pressed against the tube wall of the aluminum pipe 2 from the surface in the thickness direction.

In the optical fiber ribbon, when the compressive force is applied to the surface in the width direction and when the compressive force is applied to the surface in the thickness direction, the loss increase amount is applied in the thickness direction even with the same compressive force. Is larger.

Therefore, on both sides of the tape unit in which the optical fiber ribbon 4 is laminated in the thickness direction, the intervening tapes 3a, 3a
b, the optical fiber ribbon 4
Of the optical fiber ribbon 4 can be reduced and the compressive force applied to the surface in the thickness direction of the optical fiber ribbon 4 can be reduced, and an optical fiber cable having excellent bending and tensile characteristics can be provided.

[0021]

The present invention will be described with reference to specific numerical values, but the present invention is not limited thereto.

Six eight-core optical fiber tapes 4 each having a thickness of 0.3 mm and a width of 2.1 mm are laminated, and interposed tapes 3 a and 3 b each having a thickness of 0.3 mm and a width of 2 mm made of a polyamide resin are laminated on both sides thereof. An optical unit obtained by arranging, twisting at a pitch of 300 mm, and applying a polyester tape as the holding tape 5 was housed in the aluminum laminate sheath 1 to obtain an optical fiber cable.

The space between the optical fiber tape cores 4 is not filled with resin or the like, but can be freely moved, so that distortion due to bending or the like can be reduced. Further, the laminated optical fiber ribbons 4 are twisted at a predetermined pitch so that the bending strain can be similarly reduced.

By arranging the intervening tapes 3a and 3b on both sides of the laminated optical fiber ribbon 4, the arrangement of the laminated optical fiber ribbon 4 is adjusted and the thickness of the optical fiber ribbon 4 is adjusted. Acts as a buffer layer for directional compression.

Here, the purpose of the present optical fiber cable is to suppress the lateral pressure from the surface in the tape thickness direction, and the optical fiber cable need not be an interposed tape as long as it has the effect (for example, a fiber-like yarn). May be something). Similar effects can be expected if the material of the interposed tape is a plastic such as a fluororesin or polyethylene other than the polyamide resin described in the embodiment.

By using the present optical fiber cable, the cost can be reduced and the demand for the optical fiber cable can be expected to increase. Further, it is expected that a small diameter and light weight can be achieved, and that the time of laying and construction can be improved.

FIG. 2 is a diagram showing ironing test results when the interposed tape is arranged on both sides of the laminated optical tape core wire and when it is not arranged. In FIG. 2, the horizontal axis indicates the ironing tension and the vertical axis indicates the ironing tension. Indicates an increase in light loss.

In the test, a change in light loss was measured when tension was applied to an R250 wheel at an angle of 135 ° and the wheel was passed therethrough. From the figure, it can be seen that, by arranging the interposition on both sides, good characteristics are exhibited also in the tensile bending test (ironing test).

[0029]

In summary, according to the present invention, the following excellent effects are exhibited.

In a structure in which an optical fiber ribbon is accommodated in a pipe, it is possible to provide an optical fiber cable having excellent bending and tensile properties.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of an optical fiber cable according to the present invention.

FIG. 2 is a diagram showing ironing test results when an interposed tape is arranged on both sides of a laminated optical fiber ribbon and when not arranged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PE sheath 2 Pipe (aluminum pipe) 3a, 3b Interposition (interposition tape) 4 Optical fiber tape core wire 5 Holding tape

Continuation of the front page (72) Inventor Osamu Arai 5-1-1, Hidaka-cho, Hitachi-shi, Ibaraki F-term in the Hidaka Plant of Hitachi Cable, Ltd. (Reference) 2H001 BB16 BB23 DD14 KK22 MM06

Claims (5)

[Claims] Claims: 1. A plurality of optical fiber ribbons are laminated,
An optical fiber cable housed in a pipe, wherein an interposition is disposed on both sides of the laminated optical fiber tape. 2. A plurality of optical fiber ribbons are laminated,
The optical fiber cable according to claim 1, wherein the optical fiber cable is twisted at a predetermined pitch and housed in the pipe. 3. The optical fiber cable according to claim 1, wherein a cushion layer is provided in a gap between the pipe and the optical fiber ribbon. 4. The optical fiber cable according to claim 1, wherein the height of the interposition is equal to or greater than the lamination height of the optical fiber ribbon. 5. The optical fiber cable according to claim 1, wherein the material of the pipe is plastic or metal.