AU604296B2

AU604296B2 - An optical cable

Info

Publication number: AU604296B2
Application number: AU11715/88A
Authority: AU
Inventors: Ferdinand Grogl
Original assignee: Alcatel NV
Current assignee: Alcatel Lucent NV
Priority date: 1987-02-24
Filing date: 1988-02-15
Publication date: 1990-12-13
Anticipated expiration: 2008-02-15
Also published as: EP0280255A3; DE3705821A1; AU1171588A; EP0280255A2

Description

I

1.

I. t N N Thisn docuent ntains the rmenmits mnade Under Section 49 and is correct for Printing.

ORIGIN.1 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-1969 COMPLETE SPECIFICATION FOR THE INVENTION

ENTITLED

"AN OPTICAL

CABLE"

The ffollowing statement is a f'ull description of' this invention, including the best method of' per'forming it known to us:- This invention relates to an optical cable element cornprising at least two lengthwise members of which at least one is an optical waveguide, and to optical cables containiiig at least one such optical cable element.

An optical /electrical cable containing an optical cable element is known which consists of several optical waveguides attached to a holding component which is loosely carried inside a tube.

An object of the present invention is to provide an optical cable element which is universally applicable in dif- Sferent constructions of optical cables.

According to the present invention there is provided an Coptical cable element comprising at least two lengthwise members of which at least one is an optical waveguide, wherein said lengthwise members and cross-threads are woven together to form a ribbon.

The cable element of the present invention is tensionproof, resistant to axial compression, and flexible, so that, if such a cable element Is processed into or used in ~~optical cables, mechanical stress is kept away from the optical waveguides. By combining two or more cable elements, high packing densities can be achieved, so that correspondfi ingly thin optical cables can be produced.

b An embodiment of an optical ,,able element and several embodiments off optical cables will now be described with reference to the accompanying drawings, in which: Fig. 1 shows a novel optical cable element; Fig. 2 shows an optical cable with a first type of construction of an optical waveguide bundle; Fig. 3 shows a second type of construction of an optical waveguide bundle; Fig. 4 shows a third type of construction of an optical waveguide bundle, and Fig. 5 shows a flat cable.

Further embodiments are contained in the following description.

The optical cable element 10 of Fig. 1 contains ten optical waveguides 1, four cushion members 2, three tensionproof and axial-compression-resistant members 3, and S cross-threads 4, which are woven together to form a ribbon.

STwo of the tension-proof and axial-compression-resistant S members 3 are disposed at the edges of the ribbon, and one in the middle, and the cushion members 2 are disposed between the tension-proof and axial-compression-resistant members 3 and the optical waveguides 1. The ribbon is preferably woven in such a way that the optical waveguides are spaced a small distance apart. The cross-threads 4 may be spaced a few mm apart. They are bonded at least to the tension-proof and axial-compression-resistant members 3 located at the edge of the ribbon, which are coated for this purpose with a suitable thermosetting adhesive, such as TPX 20-030 of Henkel.

The tension-proof and axial-compression-resistant members 3 are made of aramid- or glass-fibre-reinforced plastic or a liquid-crystal polymer. The cushion members 2 are preferably flock yarns whose diameters may also be greater than those of the optical waveguides 1. The cross-threads are preferably narrow polyester tapes.

In other embodiments, 5n optical waveguides 1, n+l tension-proof and axi 1-compression-resistant members 3, and 2n cushion members 2 (where n is an integer) are arranged as described above, with groups of five optical waveguides 1 lying side by side. If less stringent requirements are placed on tensile strength and resistance to axial compression, the cushion members 2 and/or the tension-proof and axial-compression-resistant members 3 may be omitted, or the tension-proof and axial-compression-resistant members 3 may be replaced by either tension-proof or axial-compression- V. resistant members.

o0005 o 0 Several optical cable elements can be manufactured in a single weaving process by cutting through the cross-threads at predetermined points with cutting rolls following the bonding of the cross-threads to the thermo-setting-adhesive coated lengthwise members, so that several narrow optical cable elements will be obtained from one broad element.

Fig. 2 shows an optical cable with a first type of construction of an optical waveguide bundle consisting of an 2C extruded tube 12, which is lined with a wound swellable tape K3313 of Freudenberg) 11, and a helical optical cable element 10 carried in the extruded tube. The latter is surrounded by a longitudinal swellable tape 13. The swellable tape 11, too, may be applied longitudinally and with an overlap. The tape 13 is surrounded by two oppositely wound layers 15 consisting of aramid or other threads of high tensile-strength material which are coated with a thermosetting adhesive. During the manufacture of the cable, these threads are bonded together and to an aluminium 4 i tape 16 applied over the layer 15 and surrounded by a plastic jacket 17.

A second type of construction of an op ,cal waveguide bundle, shown in Fig. 3, includes an extruded tube 12 lined with a swellable tape 11, like the optical waveguide bundle in Fig. 2. The cube 12 lined with the tape 11 contains two optical cable elements 10 which are wound in opposite directions with a gap by the hollow-tube-lapping technique.

so "o The interior of the optical waveguide bundle may be filled "°oo with a filling component and/or contain a central swellable 00 0oo cord. The optical waveguide bundle may be surrounded by the o9 0 o same tension-proof cable jacket as that shcwn in Fig. 2 or o by another type of cable jacket.

In a third type of construction of the optical 0 00 0° waveguide bundle, shown in Fig. 4, a stack of ten optical O B I 0 0 cable elements is loosely carried in an extruded plastic tube 12. The stack may be twisted to increase the flexibility of the cable core. The optical waveguide bundle may be covered jy the same tension-proof cable jacket as that shown in Fig. 2 or by another type of cable jacket.

The optical waveguide bundles described with the aid of Figs. 2 to 4 may also be regarded as optical subunits, several of which may be united into a main unit and surrounded by a common cable jacket.

Fig. 5 shows a flat optical cable consisting of an optical cable element surrounded by a wrap 18, a polyester foam sheet, and a plastic Jacket 19.

In further embodiments of optical cables, one or more optical cable elements are arranged in hollow spaces of the cable (such as an open-channel cable).

Claims

1. An optical cable element comprising at least two lengthwise members of which at least one is an optical waveguide, wherein said lengthwise members and cross-threads are woven together to form a ribbon.

2. An optical cable element as claimed in claim 1, com- prising a plurality of lengthwise members at least one of which is a tension-proof and/or axial-compression-resistant thread and another being a cushion member.

3. An optical cable element as claimed in claim 1 or 2, C C: wherein at least at the edges of the ribbon, there are j} lengthwise members which are joined to the cross-threads with adhesive.

14. An optical cable element as claimed in claim 3, wherein the ribbon contains two tension-proof and/or axial- compression-proof lengthwise threads at its edges, one cush- ion member beside each of said lengthwise threads and two or more optical waveguideQ between said cushion members. An optical cable element as claimed in claim 4, wherein at least one tension-proof and/or axial-compression- r'esistant lengthwise thread is disposed between the optical waveguides and that a cushion member is disposed on both sides of the lengthwise thread(s). NA6,. An optical cable containing at least one optical ca- ble element 4s claimed in any one of the preceding claims. An optical cable as claimed in claim 6, wherein said at least one optical cable element Is loosely carried in a hollow space. 6 8. An optical cable as claimed in claim 6 or 7, wherein said at least one optical cable element is helical and is carried inside a tube, S9. An optical cable as claimed in claim 6, 7 or 8, wherein several of said optical cable elements are united into a ribbon stack. A method of manufacturing optical cable members as claimed in any one of claims 1 to 5, wherein first a broad cable element is made in a weaving process, and several nar- rower cable elements are then formed from said broad cable S element by cutting through the cross-threads at predeter- mined points. 11. An optical cable element substantially as herein de- scribed with reference to Fig. 1 of the accompanying drawings. 12. An optical cable, substantially as herein described with reference to Figs. 3 to 5 of the accompanying drawings. DATED THIS THIRD DAY OF SEPTEMBER, 1990 ALCATEL N.V. <7 -i j