GB2085188A - An improved optical cable - Google Patents
An improved optical cable Download PDFInfo
- Publication number
- GB2085188A GB2085188A GB8129011A GB8129011A GB2085188A GB 2085188 A GB2085188 A GB 2085188A GB 8129011 A GB8129011 A GB 8129011A GB 8129011 A GB8129011 A GB 8129011A GB 2085188 A GB2085188 A GB 2085188A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tubes
- optical cable
- sheath
- optical
- cable
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 46
- 239000000463 material Substances 0.000 claims abstract description 27
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 18
- 239000004033 plastic Substances 0.000 claims abstract description 17
- 229920003023 plastic Polymers 0.000 claims abstract description 17
- 230000001681 protective effect Effects 0.000 claims abstract description 15
- 239000013307 optical fiber Substances 0.000 claims abstract description 14
- 230000002093 peripheral effect Effects 0.000 claims abstract description 5
- -1 polypropylene Polymers 0.000 claims description 8
- 239000004698 Polyethylene Substances 0.000 claims description 6
- 239000004020 conductor Substances 0.000 claims description 6
- 229920000573 polyethylene Polymers 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 229910001092 metal group alloy Inorganic materials 0.000 claims description 4
- 239000004743 Polypropylene Substances 0.000 claims description 2
- 239000004760 aramid Substances 0.000 claims description 2
- 229920003235 aromatic polyamide Polymers 0.000 claims description 2
- 230000004323 axial length Effects 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 239000007769 metal material Substances 0.000 claims description 2
- 229920001155 polypropylene Polymers 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- 238000000926 separation method Methods 0.000 claims 1
- 230000001413 cellular effect Effects 0.000 abstract description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229920000271 Kevlar® Polymers 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000004761 kevlar Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- PLZFHNWCKKPCMI-UHFFFAOYSA-N cadmium copper Chemical compound [Cu].[Cd] PLZFHNWCKKPCMI-UHFFFAOYSA-N 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000005304 optical glass Substances 0.000 description 1
- 235000019271 petrolatum Nutrition 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- KKEYFWRCBNTPAC-UHFFFAOYSA-L terephthalate(2-) Chemical compound [O-]C(=O)C1=CC=C(C([O-])=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-L 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/4429—Means specially adapted for strengthening or protecting the cables
- G02B6/4434—Central member to take up tensile loads
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4401—Optical cables
- G02B6/441—Optical cables built up from sub-bundles
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Communication Cables (AREA)
Abstract
An optical cable in which the optical fibres are protected against tensile forces comprises a central core 1 consisting of an elongate tensile-resistant reinforcing member 2 surrounded by an outer peripheral layer 3 of cellular plastics material; a plurality of plastics tubes 4 in each of at least some of which is loosely housed at least one optical fibre 5 and/or optical bundle; and an outer protective sheath 6 surrounding the tubes in such a way that the tubes are loose in the sheath. The tubes 4 are wound around the core 1 in such a way that the direction of lay of the tubes reverses at spaced positions along the cable, the deformability of the cellular plastics material and the looseness of the tubes in the sheath being such that, when the cable is stressed by a longitudinally applied tensile force, the angles of lay of the tubes are reduced to increase the effective lengths of the tubes and thereby reduce the strain that might otherwise be imparted to the optical fibre or fibres. <IMAGE>
Description
SPECIFICATION
An improved optical cable
This invention relates to optical cables for the transmission of the ultraviolet, visible and infra-red regions of the electromagnetic spectrum, which regions, for convenience, will hereinafter all be included in the generic term "light", and especially, but not exclusively, to optical cables for use in the communication field adapted for transmission of light having a wavelength within the range 0.8 to 1.9 micrometres.
The present invention provides an improved optical cable in which the optical fibres are protected against tensile forces.
According to the invention, the improved optical cable comprises a central elongate core comprising an elongate tensile-resistant reinforcing member surrounded by an outer peripheral layer of highly deformable plastics material; a plurality of formed tubes of plastics material in each of some or all of which is or are loosely housed at least one separate optical fibre and/or at least one optical bundle as hereinafter defined, which tubes are wound in a layer around the central elongate core in such a way that the direction of lay of the tubes reverses at spaced positions along the length of the cable; and an outer protective sheath surrounding the tubes in such a way that the tubes are loose in the sheath, the deformability of the deformable material and the looseness of the tubes in the sheat being such that, when the cable is stressed by a longitudinally applied tensile force, the angles of lay of the tubes are reduced to increase the effective lengths of the tubes and thereby reduce the strain that might otherwise be imparted to the optical fibre or fibres.
Since the central elongate core includes an outer peripheral layer of highly deformable material, the core can be readily twisted in opposite directions at spaced positions along its length as the angles of lay of the tubes are reduced, the tensile-resistant reinforcing member of the core continuing to provide tensile strength.
By the expression "optical bundle" is meant a group of optical fibres or a group of fibres including at least one optical fibre and at least one non-optical reinforcing fibre or other reinforcing elongate member.
By virtue of being housed loosely in a tube, limited relative movement between the or each separate optical fibre and/orthe or each optical bundle and the tube can take place when the cable is flexed.
Preferably, the tubes are laid-up around the central core in such a way that, at each separate direction of lay along the length of the cable, the tubes do not make more than one complete turn around the central core,
Preferably, each tube is of an extruded polymeric material whose molecules have been orientated to lie longitudinally with respect to the axis of the tube.
Polymeric materials of which the tubes may be made include polypropylene, polyethylene and polyethylene and terephthalate.
The or each separate optical fibre and/or the or each optical bundle preferably has a length that is not shorter than the axial length of the tube in which it is loosely housed.
The tensile-resistant reinforcing member of the central core is preferably of a non-metallic material, a plurality of fibres of aromatic polyamide sold under the Trade Mark 'Kevlar' or of non-optical glass, that may or may not be bonded with resin, being preferred. Alternatively, it may be a solid wire or a strand of wires which has been die-formed; that is to say, a strand that has been passed through a die which effects a reduction in the overall diameter of the strand. Such a compacted strand has the advantage over non-compacted strands of a higher effective Young's Modulus at low strain. The wire or strand is preferably of steel but, in some circumstances, the wire or at least one of the wires of the strand may be of a metal or metal alloy of high electrical conductivity.For example, in a die-formed strand consisting of six wires stranded around a central wire, the central wire may be of steel and the surrounding six wires of copper or, in an alternative construction, all of the wires of the strand may be of hard drawn copper or cadmium copper.
In addition to the tensile-resistant reinforcing member of the central core, elongate tensileresistant reinforcing members may be laid-up with the tubes and/or may be embedded in the sheath at spaced positions, preferably uniformly spaced positions, around the sheath. Where reinforcing members are embedded in the sheath, as described and claimed in the Complete Specification of our Patent No. 1582851 each reinforcing member may have undulations, preferably radially extending undulations, that serve to improve the mechanical bonding of the member within the sheath and the flexibility of the cable.
One or more than one elongate bare or insulated electric conductor may be laid-up with the tubes and/or may be loosely housed in one or more than one of the tubes.
The outer protective sheath of the optical cable is preferably an extruded tube of rubber or plastics material and may be provided with an oversheath, for example an oversheath of a material having a low friction coefficient, such as nylon. An undersheath may be provided around the assembly of tubes and under the outer protective sheath. Where an oversheath and/or undersheath is provided, the outer protective sheath and the oversheath and/or the outer protective sheath and the undersheath may be separated by an armouring layer or by a layer of metallic tape having on its major surfaces coatings of plastics material that may be bonded to the materials of the outer protective sheath and of the oversheath or undersheath, as the case may be.
With a view to preventing water that may enter the optical cable through a damaged sheath from travelling along the cable in interstices between the tubes and between the tubes and the sheath, these interstices may be filled throughout the length of the cable with a water-impermeable medium of a grease-like nature, a medium consisting of, or comprising as a major constituent, petroleum jelly being preferred.In this case, the sheath may be lined by at least one longitudinally extending tape of metal or metal alloy which has been transversely folded or otherwise arranged to form a tube lining the sheath and which may have on its outer face a layer of plastics material that is bonded to the material of the sheath; alternatively, the assembly of tubes with the interstices filled with the medium of a grease-like nature may be surrounded by helically applied tape or tapes of a plastics material that is impermeable to the medium of a grease-like nature.
Each tube loosely housing at least one separately formed optical fibre and/or at least one optical bundle and/or at least one elongate electric conductor may be substantially filled throughout its length with a water-impermeable medium of a grease-like or gell-like nature, provided that the desired limited relative movement between the or each separate optical fibre and/or the or each optical bundle and/or the or each electric conductor and the tube is not affected to a detrimental extent.
The invention is further illustrated by a description, by way of example, of a preferred form of optical cable with reference to the accompanying diagrammatic drawing which shows a transverse cross-sectional view of the cable, drawn on an enlarged scale.
Referring to the drawing, the cable comprises a central elongate core 1 comprising a tensile-resistant reinforcing member 2 of "Kevlar" surrounded by an outer peripheral layer 3 of cellular plastics material.
A plurality of tubes 4 of extruded polyethylene surround the core 1, the molecules of the polyethylene of each tube having been orientated to lie longitudinally with respect to the axis of the tube.
The tubes 4 are arranged helically around the core 1 in such a way that the direction of lay of the tubes reverses at spaced positions along the length of cable. In each tube is loosely housed an optical fibre 5. The tubes 4 are held together by a helically applied binder tape (not shown). An outer protective plastics sheath 6 surrounds the tubes 4 in such a way that the tubes are loose in the sheath. The deformability of the layer 3 of cellular plastics material and the looseness of the tubes 4 in the sheath 6 are such that, when the cable is stressed by a longitudinally applied tensile force, the angles of lay of the tubes are reduced so that the tubes 4 follow a more direct path and remain substantially unchanged in length despite the extension of the cable, thereby reducing the strain that might otherwise be imparted to the optical fibres.
Claims (21)
1. An optical cable comprising a central elongate core comprising an elongate tensile-resistant reinforcing member surrounded by an outer peripheral layer of highly deformable plastics material; a plurality of separately formed tubes of plastics material in each of some or all of which is or are loosely housed at least one separate optical fibre and/or at least one optical bundle as hereinbefore defined, which tubes are wound in a layer around the central elongate core in such a way that the direction of lay of the tubes reverses at spaced positions along the length of the cable; and an outer protective sheath surrounding the tubes in such a way that the tubes are loose in the sheath, the deformability of the deformable material and the looseness of the tubes in the sheath being such that, when the cable is stressed by a longitudinally applied tensile force, the angles of lay of the tubes are reduced to increase the effective lengths of the tubes and thereby reduce the strain that might otherwise be imparted to the optical fibre or fibres.
2. An optical cable as claimed in Claim 1, wherein the tubes are laid-up around the central core in such a way that, at each separate direction of lay along the length of the cable, the tubes do not make more than one complete turn around the central core.
3. An optical cable as claimed in Claim 1 or 2, wherein each tube is of an extruded polymeric material whose molecules have been orientated to lie longitudinally with respect to the axis of the tube.
4. An optical cable as claimed in Claim 3, wherein the tubes are made of polypropylene polyethylene or polyethylene terephalate.
5. An optical cable as claimed in any one of the preceding Claims, wherein the or each separation optical fibre and/or the or each optical bundle has a length that is not shorter than the axial length of the tube in which it is loosely housed.
6. An optical cable as claimed in any one of the preceding Claims, wherein the tensile-resistant reinforcing member of the central core is of anon- metallic material.
7. An optical cable as claimed in Claim 6, wherein the tensile-resistant reinforcing member of the central core comprises a plurality of fibres of aromatic polyamide.
8. An optical cable as claimed in any one of
Claims 1 to 5, wherein the tensile-resistant reinforcing member of the central core is a solid wire or a strand of wires which has been die-formed.
9. An optical cable as claimed in Claim 8, wherein the wire or at least one of the wires of the strand is of a metal or metal alloy of high electrical conductivity.
10. An optical cable as claimed in any one of the preceding Claims, wherein elongate tensile-resistant reinforcing members are laid up with the tubes.
11. An optical cable as claimed in any one of the preceding Claims, wherein elongate tensil-resistant reinforcing members are embedded in the sheath at spaced positions around the sheath.
12. An optical cable as claimed in Claim 11, wherein each reinforcing member embedded in the sheath has undulations that serve to improve the mechanical bonding of the member within the sheath and the flexibility of the cable.
13. An optical cable as claimed in any one of the preceding Claims, wherein one or more than one elongate bare or insulated electric conductor is or are laid up with the tubes.
14. An optical cable as claimed in any one of the preceding Claims, wherein one or more than one elongate bare or insulated electric conductor is or are loosely housed in one or more than one of the tubes.
15. An optical cable as claimed in any one of the preceding Claims, wherein the outer protective sheath is an extruded tube of rubber or plastics material and is provided with an oversheath of a material having a low friction coefficient.
16. An optical cable as claimed in any one ofthe preceding Claims, wherein an undersheath is provided around the assembly of tubes and under the quter protective sheath.
17. An optical cable as claimed in Claim 15 or 16, wherein the outer protective sheath and the oversheath and/or the outer protective sheath and the undersheath are separated by an armouring layer or by a layer of metallic tape having on its major surfaces coatings of plastics material that are bonded to the materials of the outer protective sheath and of the oversheath or undersheath, as the case may be.
18. An optical cable as claimed in any one of the preceding Claims, wherein interstices between the tubes and between the tubes and the outer protective sheath are filled throughout the length of the cable with a water-impermeable medium of a grease-like nature.
19. An optical cable as claimed in Claim 18, wherein the sheath is lined by at least one longitudinally extending tape of metal or metal alloy which has been transversely folded or otherwise arranged to form a tube lining the sheath and which has on its outer surface a layer of plastics material that is bonded to the material of the sheath.
20. An optical cable as claimed in any one of the preceding Claims, wherein each tube loosely housing at least one separate optical fibre and/or at least one optical bundle and/or at least one elongate electric conductor is substantially filled throughout its length with a water-impermeable medium of a grease-like or gell-like nature.
21. An optical cable substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8129011A GB2085188B (en) | 1980-09-26 | 1981-09-25 | An improved optical cable |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8031256 | 1980-09-26 | ||
| GB8129011A GB2085188B (en) | 1980-09-26 | 1981-09-25 | An improved optical cable |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2085188A true GB2085188A (en) | 1982-04-21 |
| GB2085188B GB2085188B (en) | 1984-05-23 |
Family
ID=26277015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8129011A Expired GB2085188B (en) | 1980-09-26 | 1981-09-25 | An improved optical cable |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2085188B (en) |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2152235A (en) * | 1981-07-20 | 1985-07-31 | Chevron Res | Armoured optical fibre cable for use in an optical communication system for drill hole logging |
| GB2156094A (en) * | 1984-03-14 | 1985-10-02 | Bicc Plc | Optical fibre element comprising resiliently set flexible tube |
| US4550976A (en) * | 1984-09-10 | 1985-11-05 | Siecor Corporation | Fiber optic cable with foamed plastic dummy members |
| GB2163895A (en) * | 1984-09-01 | 1986-03-05 | Fothergill Cables Limited | A cable and a method of producing same |
| GB2168824A (en) * | 1984-11-05 | 1986-06-25 | Telephone Cables Ltd | Optical fibre cables containing an electrical conductor |
| US4652323A (en) * | 1984-01-09 | 1987-03-24 | Olin Corporation | Plasma deposition applications for communication cables |
| GB2184863A (en) * | 1985-12-18 | 1987-07-01 | Telephone Cables Ltd | Optical fibre cable |
| GB2185334A (en) * | 1986-01-07 | 1987-07-15 | Bicc Plc | Elongate flexible core for optical cable |
| EP0255848A1 (en) * | 1986-08-08 | 1988-02-17 | KABEL- und DRAHTWERKE Aktiengesellschaft | Optical cable |
| US4741684A (en) * | 1984-12-31 | 1988-05-03 | Ericsson, Inc. | Optical cable with filling compound and parallel fibers |
| GB2213952A (en) * | 1987-12-18 | 1989-08-23 | Focas Ltd | Optical fibre cable helically wound on electrical conductor |
| EP0321788A3 (en) * | 1987-12-21 | 1989-10-11 | kabelmetal electro GmbH | Optical cable |
| EP0112163B1 (en) * | 1982-12-13 | 1991-07-17 | Focas Limited | Fibre optic cable arrangements |
| US10120152B1 (en) * | 2018-02-13 | 2018-11-06 | Superior Essex International LP | All dielectric self-supporting fiber optic cable |
-
1981
- 1981-09-25 GB GB8129011A patent/GB2085188B/en not_active Expired
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2152235A (en) * | 1981-07-20 | 1985-07-31 | Chevron Res | Armoured optical fibre cable for use in an optical communication system for drill hole logging |
| EP0112163B1 (en) * | 1982-12-13 | 1991-07-17 | Focas Limited | Fibre optic cable arrangements |
| US4652323A (en) * | 1984-01-09 | 1987-03-24 | Olin Corporation | Plasma deposition applications for communication cables |
| GB2156094A (en) * | 1984-03-14 | 1985-10-02 | Bicc Plc | Optical fibre element comprising resiliently set flexible tube |
| US4690499A (en) * | 1984-03-14 | 1987-09-01 | Bicc Public Limited Company | Optical fibre element housed in a tube resiliently set in a form such that its longitudinal axis follows a path greater than the rectilinear distance between points to be connected |
| EP0157516A3 (en) * | 1984-03-14 | 1987-11-25 | Bicc Public Limited Company | An improved optical fibre element |
| GB2163895A (en) * | 1984-09-01 | 1986-03-05 | Fothergill Cables Limited | A cable and a method of producing same |
| US4550976A (en) * | 1984-09-10 | 1985-11-05 | Siecor Corporation | Fiber optic cable with foamed plastic dummy members |
| GB2168824A (en) * | 1984-11-05 | 1986-06-25 | Telephone Cables Ltd | Optical fibre cables containing an electrical conductor |
| US4741684A (en) * | 1984-12-31 | 1988-05-03 | Ericsson, Inc. | Optical cable with filling compound and parallel fibers |
| GB2184863A (en) * | 1985-12-18 | 1987-07-01 | Telephone Cables Ltd | Optical fibre cable |
| GB2185334B (en) * | 1986-01-07 | 1989-10-25 | Bicc Plc | Elongate flexible core for optical cable |
| US4793685A (en) * | 1986-01-07 | 1988-12-27 | Bicc Plc | Optical cable with nonmetallic reinforcing elements |
| GB2185334A (en) * | 1986-01-07 | 1987-07-15 | Bicc Plc | Elongate flexible core for optical cable |
| EP0255848A1 (en) * | 1986-08-08 | 1988-02-17 | KABEL- und DRAHTWERKE Aktiengesellschaft | Optical cable |
| GB2213952A (en) * | 1987-12-18 | 1989-08-23 | Focas Ltd | Optical fibre cable helically wound on electrical conductor |
| EP0321788A3 (en) * | 1987-12-21 | 1989-10-11 | kabelmetal electro GmbH | Optical cable |
| US4909593A (en) * | 1987-12-21 | 1990-03-20 | Alcatel N.V. | Optical cable having at least two separate multiple-fiber units each having its own soft plastic envelope |
| US10120152B1 (en) * | 2018-02-13 | 2018-11-06 | Superior Essex International LP | All dielectric self-supporting fiber optic cable |
| US10591691B1 (en) | 2018-02-13 | 2020-03-17 | Superior Essex International LP | All-dielectric self-supporting fiber optic cable |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2085188B (en) | 1984-05-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |