WO2008015386A2 - Câble de transmission de signaux - Google Patents

Câble de transmission de signaux Download PDF

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Publication number
WO2008015386A2
WO2008015386A2 PCT/GB2007/002802 GB2007002802W WO2008015386A2 WO 2008015386 A2 WO2008015386 A2 WO 2008015386A2 GB 2007002802 W GB2007002802 W GB 2007002802W WO 2008015386 A2 WO2008015386 A2 WO 2008015386A2
Authority
WO
WIPO (PCT)
Prior art keywords
signal transmitting
layer
cable
transmitting cable
optical fibre
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.)
Ceased
Application number
PCT/GB2007/002802
Other languages
English (en)
Other versions
WO2008015386A3 (fr
Inventor
David John Stockton
Jonathan Paul Taylor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Emtelle UK Ltd
Original Assignee
Emtelle UK Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from GB0615183A external-priority patent/GB0615183D0/en
Priority claimed from GB0700003A external-priority patent/GB0700003D0/en
Application filed by Emtelle UK Ltd filed Critical Emtelle UK Ltd
Publication of WO2008015386A2 publication Critical patent/WO2008015386A2/fr
Publication of WO2008015386A3 publication Critical patent/WO2008015386A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • G02B6/443—Protective covering
    • 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
    • G02B6/4402—Optical cables with one single optical waveguide

Definitions

  • the present invention relates to signal transmitting cables, and relates particularly, but not exclusively, to optical fibre signal transmitting cables.
  • Optical fibre cables carry data at very high speeds and as the demand for 'Broadband' internet access grows, there is an increasing requirement for optical fibre cables providing high speed connection to be deployed directly into individual homes or business premises.
  • optical fibres which needs to be provided to each individual home or business premises is relatively small. In fact, it is often possible to provide adequate high speed services to an individual home using an optical fibre cable having just one optical fibre.
  • Typical applications of such optical fibre cables are, for example, providing optical fibre connections to individual premises to provide very high speed broadband internet connections, TV, video and telephony. This application is known as "Fibre to the Home” (FTTH).
  • FTTH Fiber to the Home
  • optical fibre networks are constructed by setting up a network of tubes, and then subsequently installing the optical fibre cables into the tube network, usually by means of a combination of blowing by means of compressed air, and pushing by means of rollers.
  • EP0108590 describes the basic process of using fluid drag to install optical fibre cables in tubes. The blowing process distributes the installation force along the entire length of the optical fibre cable, and it is desirable for optical fibre cables to have adequate stiffness to facilitate installation by means of blowing. Such stiffness is generally provided by means of reinforcement of the optical fibre cable.
  • EP 0157610 discloses an optical fibre cable comprising: one or more optical fibres; an inner sheath having an elastic modulus of 1000 MPa; and an outer sheath having an elastic modulus of less than 1000 MPa.
  • an inner sheath having a relatively high elastic modulus the optical fibre cable possesses the required stiffness to facilitate installation by means of blowing, without being too bulky.
  • the optical fibre cable of EP 0157610 suffers from the disadvantage that it is inflexible, which inhibits blowing performance particularly in the case where the optical fibre is to follow a curved installation path. This inflexibility potentially negates any positive effects of having the required stiffness to facilitate blowing.
  • EP 0296836 discloses an optical fibre cable comprising: one or more optical fibres; an inner sheath having an elastic modulus of less than 100 MPa; and an outer sheath.
  • an inner sheath having a relatively low elastic modulus any stresses arising within the cable are distributed in a reasonably uniform fashion, and a degree of flexibility is provided to the optical fibre cable.
  • the optical fibre cable of EP 0296836 suffers from the disadvantage that the inner layer, having a relatively low elastic modulus, offers little "crush" resistance. Moreover, since the stiffness is directly proportional to the elastic modulus, little additional stiffness is conferred by the inner layer, and it is left to the outer sheath to provide the additional stiffness required for installation by means of blowing. Preferred embodiments of the present invention seek to overcome or at least alleviate the above disadvantages of the prior art.
  • signal transmitting cable comprising a signal transmitting portion including at least one signal transmitting member, a first layer of at least one radiation curable material surrounding said signal transmitting portion, wherein said first layer has an elastic modulus greater than 100 MPa but less than 1000 MPa, and a second layer of at least one radiation curable material arranged outwardly of the first layer, wherein the second layer has an elastic modulus higher than that of the first layer
  • the present invention is based upon the discovery that cables having enough stiffness required to facilitate installation by means of blowing, yet enough flexibility so as not to prohibit installation by the same process, can be manufactured by providing a first layer having an elastic modulus within the range specified above.
  • This provides the advantage that the stiffness required to facilitate installation by means of blowing is provided, even in the case of a relatively thin first layer, whilst still allowing sufficient flexibility to facilitate installation by means of blowing, particularly in non-linear underground ducts where installation of an inflexible cable would be inhibited.
  • the use of radiation curable material provides good blowing and temperature performance, while also making it easy to strip the coatings from the cable when optical fibre connections are to be made.
  • the use of a second layer of higher elastic modulus than that of the first layer and arranged outwardly of the first layer provides the further advantage of giving further protection to the cable while enabling various additives to be used which further improve the blowing performance of the cable.
  • the second layer may have a thickness less than or equal to the thickness of the first layer.
  • Outer layers of optical fibre cables are sometimes modified to include a particle coating or inclusion which improves blowing performance.
  • This type of outer layer is expensive. In having a relatively tough first layer however, the thickness of the outer layer may be made to be thinner. This provides the advantage that the manufacturing costs of the optical fibre cable may be reduced. In having a thinner outer layer, this provides the further advantage that the outer layer may be stripped away from the first layer more easily, when required.
  • the second layer may have a thickness of approximately 10% of the thickness of the first layer.
  • the signal transmitting portion may include a single signal transmitting member.
  • the first layer may have an outer diameter of approximately 0.4 to lmm.
  • This provides the advantage of making the optical fibre cable more compact, which reduces congestion in already crowded underground ducts.
  • the second layer may include at least one anti-static agent.
  • At least one anti-static agent may comprise a quaternary ammonium compound containing methanol.
  • the coefficient of dynamic friction of the second layer is less than or equal to 0.25.
  • a signal transmitting cable comprising a signal transmitting portion including at least one signal transmitting member, and a first layer surrounding said signal transmitting portion, wherein said first layer includes undissolved particulate matter dispersed therethrough.
  • the particulate matter may comprise aluminium trihydrate and/or antimony trioxide and/or zinc hydroxystannate.
  • the coefficient of thermal expansion of the first layer is approximately 5 x 10 "5 /C below T g and 1.5 x 10 "4 /C above T g , whereTg is the glass transition temperature.
  • a signal transmitting cable comprising a signal transmitting portion including at least one signal transmitting member, and a first layer surrounding said signal transmitting portion, wherein the first layer is made from at least one filled, fire retardant material.
  • optical fibre cable is provided with improved resistance to fire.
  • a filled acrylate material has been found to be effective. The reason for this is as follows. Conventional acrylate materials frequently burn at room temperature when subjected to an ignition source. This is because conventional acrylates have a limiting oxygen content (LOI) of approximately 20, which means that they burn at an atmospheric level of 20% oxygen (as occurs naturally). However, filled acrylates have an LOI of typically about 30 and so resist burning under room temperature conditions. In view of this, optical fibre cables having a filled acrylate first layer are capable of passing fire tests such as UL 1581, UL 1666 and UL 1685.
  • LOI limiting oxygen content
  • Figure 1 is a schematic cross-sectional view of a cable of a first embodiment of the present invention
  • Figure 2 is a schematic cross-sectional view of a cable of a second embodiment of the present invention.
  • Figure 3 is a schematic cross-sectional view of a cable of a third embodiment of the present invention.
  • Figure 4 is a schematic cross-sectional view of a cable of a fourth embodiment of the present invention.
  • an optical fibre cable 2 comprises a single optical fibre 4, surrounded by a first layer 6, which itself is surrounded by a second layer in the form of an outer layer 8.
  • the outer layer 8 is formed from a UV-curable acrylate resin material having secant modulus of 250 to 500 Mpa, and is in touching contact with the first layer 6, and is arranged outwardly of the first layer 6.
  • the first layer 6 is made from material having an elastic modulus of greater than or equal to 100 MPa and less than 1000 MPa.
  • the thickness of the outer layer 8 is approximately 10 microns, and the thickness of the first layer 6 is approximately lmm.
  • the optical fibre cable of the present invention possesses the required stiffness to facilitate installation by blowing in underground ducts, yet is not so inflexible that its installation in non-linear underground ducts is impeded.
  • the outer layer 8 includes an anti-static agent in the form of a quaternary ammonium compound containing methanol. Moreover, the coefficient of friction of the outer layer 6 is approximately 0.25.
  • an optical fibre cable 2a comprises a single optical fibre 4, surrounded by a first layer 6a, which itself is surrounded by a second layer in the form of an outer layer 8a.
  • the outer layer 8a is arranged outwardly of the first layer 6a.
  • the first layer 6a has undissolved particulate matter 10 dispersed therethrough.
  • the particulate matter 10 serves to reduce the coefficient of thermal expansion of the first layer 6a, and in this way, the coefficient of expansion of the first layer 6a is approximately 5 x 10 ⁇ 5 /C below T g and 1.5 x 10 " /C above T g , where Tg is the glass transition temperature, as will be familiar to persons skilled in the art.
  • an optical fibre cable 2b comprises a single optical fibre 4, surrounded by a first layer 6b, which itself is surrounded by a second layer in the form of an outer layer 8b.
  • the outer layer 8b is arranged outwardly of the first layer 6b.
  • the first layer 6b is made from a filled acrylate material, and in this way, the first layer 6b resists burning under room temperature conditions.
  • an optical fibre cable 2c is similar to that shown in Figure 1 , but for the provision of a plurality of optical fibres 4.
  • figures 5 is similar to Figure 2 but for the provision of a plurality of optical fibres 4
  • figure 6 is similar to Figure 3 but for the provision of a plurality of optical fibres 4.
  • the signal transmitting cable may include additional layers other than the first and second layers discussed above.
  • the signal transmitting cable may include any number of optical fibres.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Communication Cables (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Surface Treatment Of Glass Fibres Or Filaments (AREA)

Abstract

L'invention concerne un câble (2) de fibre optique qui comprend une fibre optique (4), une première couche (6) d'au moins un matériau durcissable par rayonnement ayant un module élastique supérieur à 100 MPa mais inférieur à 1000 MPa, et une seconde couche (8) faite d'au moins un matériau durcissable par rayonnement, disposée à l'extérieur de la première couche et ayant un module élastique supérieur à celui de la première couche.
PCT/GB2007/002802 2006-07-29 2007-07-24 Câble de transmission de signaux Ceased WO2008015386A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB0615183A GB0615183D0 (en) 2006-07-29 2006-07-29 Signal transmitting cable
GB0615183.1 2006-07-29
GB0700003A GB0700003D0 (en) 2007-01-02 2007-01-02 Signal transmitting cable
GB0700003.7 2007-01-02

Publications (2)

Publication Number Publication Date
WO2008015386A2 true WO2008015386A2 (fr) 2008-02-07
WO2008015386A3 WO2008015386A3 (fr) 2008-03-27

Family

ID=38657195

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2007/002802 Ceased WO2008015386A2 (fr) 2006-07-29 2007-07-24 Câble de transmission de signaux

Country Status (1)

Country Link
WO (1) WO2008015386A2 (fr)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2149802B (en) * 1983-11-16 1987-03-18 Standard Telephones Cables Ltd Oil resistant flame retardent ethylene polymer compositions
NL8702395A (nl) * 1987-10-08 1989-05-01 Philips Nv Optische vezel voorzien van een kunststofbedekking.
GB8911959D0 (en) * 1988-05-28 1989-07-12 Ici Plc Coated optical fibres
FR2793320B1 (fr) * 1999-05-06 2002-07-05 Cit Alcatel Cable a fibre optique a proprietes ameliorees
US6630242B1 (en) * 1999-07-30 2003-10-07 Dsm N.V. Radiation-curable composition with simultaneous color formation during cure
DE60032944T2 (de) * 1999-12-30 2007-10-18 Corning Inc. Sekundärbeschichtung für lichtleitfasern
JP2003322775A (ja) * 2002-04-30 2003-11-14 Furukawa Electric Co Ltd:The 光ファイバ素線
US6973245B2 (en) * 2003-12-30 2005-12-06 Furukawa Electric North America Optical fiber cables

Also Published As

Publication number Publication date
WO2008015386A3 (fr) 2008-03-27

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