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
  • G02B6/24—Coupling light guides
  • G02B6/36—Mechanical coupling means
  • G02B6/38—Mechanical coupling means having fibre to fibre mating means
  • G02B6/3801—Permanent connections, i.e. wherein fibres are kept aligned by mechanical means
• • 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
  • G02B6/4407—Optical cables with internal fluted support member

Definitions

• the present invention relates to a method and to a device for splicing together one or more optical-fibre cables.
• the splicing and branching of an optical-fibre cable requires the use of special devices to ensure satisfactory handling of the fibres, for instance to ensure that the optical-fibres are not bent excessively, are not pinched or subjected to load in any other way. It is particularly important that the optical-fibre is not curved to a radius that exceeds a specified smallest bending radius. Bending of an optical- fibre induces in the fibre stresses that have a negative effect on the useful life of the fibre, while excessive bending of the fibre will cause the light to be transmitted out of the fibre and result in undesired attenuation.
• Splicing of optical-fibres also requires the ability to store optical-fibre slack in the splicing box. This is necessary primarily because welding equipment is often used to splice optical-fibres and because correct use of the equipment requires the presence of sufficient fibre slack in the splicing box.
• the ends of two optical-fibres to be spliced together are placed in the welding device and subsequent to splicing the fibres the spliced optical-fibre is coiled-up or folded in a controlled manner such as to ensure that the fibre will not be bent or curved excessively.
• the boxes contain variants of systems that use fibre cassettes in which fibre slack is wound up and in which a weld splice and its protective sleeve can be mounted.
• a plurality of cassettes are normally required when fibre cables that contain a large number of optical-fibres are to be spliced together, which results in large and expensive splicing boxes.
• a cable splice takes a relatively long time to make.
• an object of the present invention is to provide a cheaper and simpler fibre splicing device in which fibre slack can be handled more easily and bending radii controlled more readily and with which it is ensured that the optical- fibre is subjected to no load.
• a cable splice is made with the aid of a cylindrical body having, for instance, two narrowing ends each of which includes one or a number of holes.
• Two optical-fibre cables are spliced together by first placing a tension-relieving core from each optical-fibre cable in a respective hole in the body and then securing the cores by means of a screw or like fastener.
• the cable splice is therewith relieved of tension by means of the cylindrical body.
• the optical-fibres in the cables are joined together to provide a fibre splice, which is protected by a sleeve.
• the cylindrical body includes a section that has one or more grooves.
• each groove is adapted to the size of the sleeve and the grooves are used to fixate the sleeve and its fibre splice.
• the problem of producing a splice in which the smallest bending radius is ensured and the problem of correct handling of excess fibre and relieving the cable of tension forces at the same time is solved by means of the present invention in a simple and inexpensive manner.
• the splice is straight and compact and can also be placed within a tubular duct, for instance.
• Figure 1 is a perspective view of a typical optical-fibre cable.
• Figure 2 illustrates an inventive splicing device.
• Figure 3 illustrates an inventive splicing device on which a protective sleeve is fitted.
• Figure 4a is a cross-sectional view taken on the line A-A in Figure 3.
• Figure 4b is a cross-sectional view taken on the line B-B in Figure 3.
• Figure 5 illustrates an alternative embodiment of the invention and shows both splicing and branching.
• Figure 6a is a cross-sectional view taken on the line C-C in Figure 5.
• Figure 6b is a cross-sectional view taken on the line D-D in Figure 5.
• Figure 7 illustrates an alternative embodiment of a cylindrical body in accordance with the invention.
• Figure 1 is a perspective view of a typical optical-fibre cable 1 that includes a casing for protecting one or more embedded optical-fibres 2 against external forces.
• the optical-fibres may be placed singly or may be grouped in an optical ribbon.
• the optical-fibre cable may also include a tension-relieving element 3, which in the illustrated case is placed as a cylindrical core in the centre of the optical- fibre cable.
• FIG 2 illustrates an inventive splicing device in which two optical-fibres cables 1, 1' are fitted, and shows the tension-relieving cores 3, 3' of the cables fastened to a cylindrical body 4 by means of a respective screw 5, 5' provided on a respective side of the body. It will be understood that the tension-relieving core may also be secured in some other way, for instance glued.
• Each optical- fibre cable includes one or more optical-fibres 2, 2' . In the illustrated case, these fibres are represented by two single fibres from each optical-fibre cable, for the sake of simplicity.
• An optical-fibre 2 from one optical-fibre cable 1 is spliced to an optical-fibre 2' from the other optical- fibre cable 1' and the splice protected by a sleeve 6.
• the splice, or join may be a welded or mechanical splice, e.g. effected with the aid of so-called optical contacts in the latter case.
• the remaining optical-fibres are mutually joined in a similar way and protected by a sleeve that functions as a mechanical guard.
• the cylindrical body also includes a grooved section 7 that has one or more grooves 8.
• the grooves are adapted to the shape of the protective sleeves 6 and function to secure the sleeves.
• the grooves 8 preferably extend along the cylindrical body.
• the grooved section is located in the vicinity of the centre of the cylindrical body 4.
• Figure 3 illustrates the same device as that illustrated in Figure 2 and shows the optical-fibres 2, 2' wound around the cylindrical body 4 and the protective sleeves 6 placed in appropriate grooves 8.
• the splicing device is placed inside a protective casing 9.
• the casing may have the form of a tube provided with connections at both ends, and may consist of two moulded halves or may be an integral moulded structure. In the latter case, the casing 9 surrounds the two optical- fibre cables 1, 1' and has bevelled edges 10.
• Appropriately labelled sleeves enable individual optical-fibres and splices to be easily identified.
• Figure 4a is a cross-sectional view taken on the line A-A in Figure 3.
• the cross-section cuts through the cylindrical body 4 and the protective sleeve 9 at the attachment of the first optical-fibre cable 1.
• the tension-relieving core 3 of the optical-fibre cable is secured with the aid of a screw 5 and the two optical-fibres 2 lie around the cylindrical body 4.
• the optical-fibres need not lie in abutment with the cylindrical body 4, but may be located in the region between the cylindrical body 4 and the protective casing 9.
• Figure 4b is a cross-sectional view taken on the line B-B in Figure 3.
• the cross-section cuts through the cylindrical body 4 and the protective casing 9 at the grooved section 7.
• a plurality of grooves 8 are disposed around the periphery of the cylindrical body so as to hold the protective sleeves 6 and their spliced optical-fibres 2 in place.
• Figure 5 illustrates an alternative embodiment of an inventive splicing device, in which two optical-fibre cables 14, 15 are fastened to a first end of a cylindrical body 11 having partially planar sides and two optical-fibre cables 14', 15' are fastened to a second end of said body.
• this embodiment also enables optical-fibres to be branched.
• One optical-fibre 12 is spliced with an optical-fibre 12' , which are both wound around the body 11.
• the splice is protected by a sleeve 6 placed in a groove 8. This describes a splice in the absence of a branch.
• An optical-fibre 13 is spliced to an optical- fibre 13' and the optical-fibres are also wound around the body 11.
• the splice is similarly protected by a sleeve 6 and placed in a groove 8.
• the splicing device is constructed in the same way as that described earlier with reference to Figure 3.
• FIG. 6a is a cross-sectional view taken on the line C-C in Figure 5, in which the cylindrical body 11 has partially planar sides 23 and has four optical-fibres 12, 13, 16, 17 disposed therearound.
• the tension-relieving cores 18, 19 from respective incoming optical-fibre cables 14, 15 are secured by means of a respective groove 20, 21.
• the embodiment includes the externally mounted protective casing 22.
• Figure 6b is a cross-sectional view taken on the line D-D in Figure 5 and shows the grooved section of the cylindrical body 11 having partially planar sides.
• the grooved section includes a plurality of grooves 8 in which the protective splice sleeves 6 are placed.
• Figure 7 illustrates an alternative embodiment of a cylindrical body 24 of an inventive splicing device.
• the body is curved so that its ends point in one and the same direction.
• Each end 25 includes a recess 26 for accommodating an element that functions to relieve the tension in the cable and which is secured by means of a fastener device 27.
• the spliced optical-fibres and the splices are disposed around the curved cylindrical body, with the splices protected by a sleeve placed in a groove 28.
• the optical-fibre is unable to bend about a radius that is smaller than the radius of the cylinder.
• the cylinder body may, alternatively, be given a radius that is smaller than the smallest permitted bending radius of the optical-fibre, provided that the fibre is wound as a toroid around the cylindrical body.
• All embodiments include a grooved section disposed around the periphery of the cylindrical body, although this grooved section is not necessary with respect to the function of the device. However, the grooves in the grooved section simplify handling of the optical-fibres. It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof and that modifications can be made within the scope of the following Claims.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Mechanical Coupling Of Light Guides (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20402032

Family Applications (1)

Country Status (3)

Cited By (3)

Citations (2)

• 1996
  • 1996-03-29 SE SE9601240A patent/SE507117C2/sv not_active IP Right Cessation
• 1997
  • 1997-03-25 WO PCT/SE1997/000516 patent/WO1997037263A1/en active Application Filing
  • 1997-03-25 AU AU25248/97A patent/AU2524897A/en not_active Abandoned

Patent Citations (2)

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