JPS5859405A - Optical communication cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical communication cable comprising a cable core having an optical fiber and a synthetic resin sheath surrounding the cable core and having a tensile force absorbing glass fiber element.

It is known to provide glass fiber bundles to eliminate tensile stresses in the synthetic resin sheath of optical communication cables, especially overhead cables. Such structures have already been used for many years. In the case of cables with optical waveguides, it is known that shrinkage effects occur in the sheath of thermoplastic materials, such as polyethylene, so that in unfavorable conditions, the There is a risk that the optical waveguide will increase in size or be destroyed.

It is an object of the present invention to provide an optical communication cable of the kind described at the beginning of the present specification in which the shrinkage effect in the cable sheath does not increase the attenuation of the optical waveguide in the cable core or that the optical waveguide is The objective is to modify the optical communication cables so as not to damage the wave paths.

According to the invention, this object is achieved by forming the glass fiber elements into at least one uniform strand by means of a synthetic resin binder, and by forming the glass fiber elements into at least one uniform strand in the cable sheath. 10 volume and the proportion of these glass fiber elements in the strand to 70 volume.
shall be.

In particular, the present invention provides that the tensile and shear stresses in an overhead cable are reduced by glass fist fiber strands in the cable sheath such that the shear stress conditions in the sheath match the shear stresses of the optical waveguide in the cable core. This was done based on the recognition that the decision was made. In contrast to known cable constructions, the present invention provides that not only is there a pull up element in the cable sheath, but also that the glass fiber element present in the cable sheath is This is based on the fact that there is a need to influence the shear stress so that the contraction of the cable sheath is suitable for matching the contraction of the optical fiber in the cable core. Advantageously, the capacity of the glass fibers in the strand is 80 mm.

According to a preferred embodiment of the invention, the glass fiber strand may be configured as a tube that substantially forms the cable sheath and thus replaces the outer sheath. Alternatively, it may be advantageous to form the glass fiber strands according to the invention as rounded wires.

The wires may run parallel to the long axis of the cable or may be twisted.

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

As shown in FIG. 1, an optical communication cable consists of two optical waveguides 1 surrounded by a hard coating 1a of, for example, synthetic resin.

These optical waveguides l are entangled around a core strand δ having two strands of synthetic resin. The cable rope number obtained in this way is surrounded by a foil 6 of a highly conductive synthetic resin, which is further surrounded by a hose 7, as a result of which mechanical stresses of all kinds, e.g. bending stresses, vibrations, etc. It can provide optimal protection against stress and lateral forces. Preferably, the hose 1 is constructed from polyvinylidene fluoride.

This hose 7 seals the cable core.

The tube 9 consists of unidirectionally bonded glass -7 eyeglass fibers 10, each of which is reinforced with a binder 11, in particular of L-ester resin. This tube 9 essentially forms the outer sheath of the cable. The proportion of glass fiber IO in this tube is at least 70 volumes, t*.

Preferably, the capacity is 80%. Preferably, the diameter of the glass 7-iper lO is 28 μm and it is made of E° glass. E-glass lacks alkali and has O+ Na, O less than 1-. By using a glass with a higher E-module than E-glass, the elastic modulus of this tube can be improved. The coefficient of thermal expansion of this tube 9 is approximately No XJ O-6/°C. Also, the wall thickness of the tube is approximately 2 mm. A separating foil 8 is provided between this tube 9 and the cable core underneath. This tube 9 behaves in a manner compatible with the optical waveguide fiber in such a way that it absorbs the shear stresses occurring in the sheath, especially due to shrinkage and tensile stresses, and avoids an increase in attenuation in the optical waveguide due to shrinkage stresses. Surrounding the tube 9 is a cladding 18, preferably made of polypropylene and having a thickness of approximately 0.6 mm, which cladding is for protection from the atmosphere.

FIG. 2 is a sectional view showing another embodiment of the cable according to the invention, which cable includes, for example, two optical waveguides l.
These optical waveguides are entwined around a core strand with a synthetic resin strand 2 with a length of approximately 65 twists.

On top of this is a layer 14 of foamed foil approximately 0.9 mm thick. High-pressure polyethylene hose 15 with a thickness of 1.8
to form the outer seal of the cable core. The outer sheath is formed, like the tube 9 in FIG.
The long twist length is, for example, 4α01aI. The proportion of glass fibers per unit strand is in this case also at least 70 volumes, and the outer seal is provided with a cladding 17 corresponding to the outer seal of FIG.
formed by The cable shown in FIG. 2 has an overall diameter of approximately 140 mm. As with the cable shown in Figure 1, there is contrast in that there is no metal at all.

The cables shown in FIGS. 1 and 2 are both configured for relatively high tensile loads, so that the cable
The large volume of material of the glass fiber strands in the sheath is explained.

FIG. 8 is a cross-sectional view of another embodiment of a cable according to the invention, which also absorbs tensile and shear stresses (
(take up) A reinforcing strand 80 is constructed with glass fibers 10 reinforced with a binder 11 according to the streak strand of FIG. These reinforced strands IAO, cable core 8! embedded in a cladding 21 for sealing.

In this case also, the reinforcing strands per strand 2
0 glass fiber has at least 0 capacitance.

The proportion of strands 20 in the cladding may be, for example, 10 volumes. In this case, the cable according to the invention is configured not only for tensile loads, but also for shear stresses to be absorbed by the strands, since the strands essentially serve as a corset of the sheath and determine their behavior.

FIG. 4 is a sectional view showing still another structure according to the present invention. In this case, a core winding portion 28 is provided around the cable core 22 as an open coil. Again, the reinforcing strands 20 correspond structurally to the strands shown in FIG. 8, and these strands are in the form of wires. These strands 20 are provided above the core winding portion 28. The open structure of this core winding 28 allows these reinforcing strands 20 to be at least partially surrounded by the cladding 21. Again, the proportion of glass fibers in the reinforcing strands 20 bonded by the binder is at least 70%.

The cable according to the invention can be used as a self-supporting overhead cable or, in some applications, as an underground cable. These cables are characterized by the high capacity and wide span width of the glass fiber strands, and in addition, the sheath of these cables
Since the leading waveguide in the core behaves in a temperature-compensated manner, even if there is a temperature-dependent shrinkage stress, the attenuation in the optical waveguide will not increase, and there is no risk of breaking the optical waveguide.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of the optical communication cable according to the present invention, FIG. 2 is a schematic cross-sectional view showing another embodiment of the optical communication cable according to the present invention, and FIG. 8 is a schematic cross-sectional view showing another embodiment of the optical communication cable according to the present invention. Schematic sectional view for explaining the principle of the cable. FIG. 1 is a schematic sectional view for explaining the principle of another embodiment of the cable according to the present invention. l... Optical waveguide 1a... Coating 2.1
6... Strand 8... Core strand 4...-Cable rope b... Foil 7.15.1. Hose 8...
Separation foil 9◆...Tube 10...Glass fiber 11...Binding agent 1j! , 17.21... Clad 14... Layer 20... Reinforced strand 22
... Cable core 28 ... Core winding part. Patent Applicant N.B.Philips Fluiran Penfapriken

Claims (1)

[Scope of Claims] 1. An optical communication cable consisting of a cable core having an optical fiber and a synthetic resin sheath having a glass fiber element surrounding them and absorbing tensile force, wherein the glass fiber element ( io) formed into at least one uniform strand (9, 16, 20) by means of an e-plastic binder (11), the glass fiber elements being at least 10% by volume in the glass sheath and An optical communication cable, characterized in that the proportion of these i 5 -s fiber elements in the strand is at least F00 capacity. Optical communication cable according to claim 1, characterized in that said glass fiber element (10) has at least 80 capacitance arcs in said strand (9, 16, 20). 3. The optical communication cable according to claim 1, wherein the glass fiber element (10) is composed of glass fibers coupled in one direction. 9. The optical communication cable according to claim 1, wherein the glass fiber (10) is made of E glass. 5. An optical communication cable according to any one of claims 1 to 4, characterized in that the strand (#1) is constituted by a tube (9) substantially forming a cable sheath. a. Any one of claims 1 to 4, characterized in that several strands (16e'; Optical communication cable described in . 7. The optical communication cable according to claim 6, characterized in that the strand (16) extends parallel to or is intertwined with the long axis of the cable. & Optical communication cable according to any one of claims 5 to 7, characterized in that the front pipe (9) and the strand (16°20) are each surrounded by an outer cladding (17°21) of synthetic resin. . 9. Optical communication cable according to claim 6 or 7, characterized in that the m strands (20) are at least partially embedded in the cladding (21). lα The optical communication cable according to any one of claims 1 to 9, characterized in that the cable is temperature compensated. Optical communication cable according to any one of claims 1 to IO, characterized in that IL polyester is used as a binder.