1、 Bs Y862591 0678835 549 m INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Construction, installation, jointing and protection of optical fibres cables (I 994 Edition) Geneva 1994 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION
2、 SECTOR OF ITU Construction, installation, jointing and protection of optical fibres cables (1 994 Edition) Geneva 1994 ISBN 92-61 -04901 -X 88 4862593 0678837 3LL R O ITU 1994 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or m
3、echanical, including photocopying and microfilm, without permission in writing from the ITU. Chapter I . Cable construction 1 General . 1.1 Purpose of cable construction for optical fibre . 1.2 Advantages of Optical Fibre Cables . 1.3 Cable application and design factors Mechanical and environmental
4、 characteristics . 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Residual fibre strain 2.1.1 Causes . 2.1.2 Effects . 2.1.3 Constructional Considerations Impulsive fibre strain 2.2.1 Causes . 2.2.2 Effects . 2.2.3 Constructional considerations . Fibre macrobending 2.3.1 Causes . 2.3.2 Effects . 2.3.3 Constr
5、uctional considerations . 2.4.1 Caus and afterwards a final A.3.2 A.3.3 A.3 Chapter VII . Cables inside buildings 1 Generai . 1.1 Purpose of Optical Fibre Cables Inside Buildings 1.2 Application of Optical Fibre Cables Mide Buildings 1.3 Extemal Factors 1.4 Types of Appmm . Environmental and Mechani
6、a Characteristics . 2.2 Appantus Cabinets, - climatic performance; 14 chap. I E 4862,493 0678857 T82 airtightness, moisture penetration resistance mechanical stability (bending, torsion, radiai pressure, tension, abrasion, etc.); chemical resistance; diameter; weight; fire resistance rodent resistan
7、ce GroaUe Coated fibre Gmd seconciary potectd fibre unii (1 to 10 fibres and 5b 10 sbis) sheathwrai strength- Fibre ribbon ctack to 18ribbons) (2to 12fbres andup Sbtted rod strenlmenber 2oFtwes (4 fibre ribbons x 5 ribbons) FIGURE 6/I Exampies of siqgle unit cable canstnxtions chap. I 15 4Bb259L Ob7
8、BBb0 iT4 sheaai opcal fire unit Optical fibre unit Cheath Tube coated Loose sacaidary protected fibre mit (2 to 12 fibres witti 1 to 20 tubes) fibre Ctrength member Groove FIGURE 7a/I Examples of dtiple unit cable cxmkwth 3.4.1 Cable Sheath Types Various kinds of cable sheath have been introduced fo
9、r opticai fibre cables applied to both external and internal installations. These are classified into the foliowing five types: - - plastic sheath only, - - - cable sheath with armour. metal/plastic sheath with metallic tapes or metallic layer, plastic sheath with strength members, plastic sheath wi
10、th embedded strength members with a metallic tape, Typical application of them is various environmental conditions is shown in Table 7/I. 16 chap. I I 4862591 Ob78861 b30 m FIGURE 7WI Examples of muiipe mit cable amsuc OIS 3.4.2 MeWplastic sheath with metallic tapes or metallic layer This type of ca
11、ble sheath has a metallic moisture barrier tape and in some of these constructions an impervious barrier is achieved. The metallic tape may be corrugated to improve the flexibility and crushing strength of the cable. 3.4.2.1 MetaVPlasic bonded sheath with coated duminium tape This type of sheath inc
12、orporates a tape of aluminium which is usually coated on one side with a thin film of polyolefin or copolymer. The coated aluminium tape is laid longitudinally over the cable core with the coated side outwards so as to form a tube with an overlap. A polyolefin sheath is then extruded over the tape a
13、nd the coating fuses to the extruded sheath to provide a firm bond between it and the aluminium tape. Aluminium tape coated on both sides may be used when it is necessary to seal the overlap to improve the moisture barrier or to avoid sheath circulating current. chap. I 17 W Y862591 0678862 577 W Ca
14、ble sheath types Metdplastic sheath with metallic tapes or metallic layer Plastic sheath only Plastic sheath with strength members Plastic sheath with embedded strength members with metallic tape 3.4.2.2 Metallplastic bonded sheath with coated steel tape This type of sheath incorporates a tape of st
15、eel coated on both sides with a thin film of copolymer. This tape is corrugated and laid longitudinally over the cable core as to fonn a tube with an overlap, along which the copolymer is fused to ensure a fixm bond. A plastic sheath such as polyethylene is then extruded over the tape. External cabl
16、es Aerial Buried Duct Tunnel A A A A A B A A A A A A A A A A TABLE 7A Typical application of cable sheath types in various environmental conditions Cable sheath with armour A A B B Underwater B B B B A Internal Building i AI i A = Typically applied type B = Rarely applied type 3.4.2.3 This type of s
17、heath includes a longitudinally applied aluminium tape formed into a tube over which is a similar tube of tinned-steel in contact with it. The edges of the tinned-steel tape are overlapped and soldered. For large cables both tapes are corrugated to improve flexibility. A layer of compound is applied
18、 over the tinned-steel tube before a plastic sheath is extruded over it for corrosion protection. This sheath forms an impervious moisture barrier. MetaYplastic sheath with aluminium tape and soldered hed-steel tape 3.4.2.4 This type of sheath includes a longitudinally applied steel tape formed into
19、 a tube with its edges continuously welded together. The tube is then corrugated down onto the cable core. A layer of compound is applied over the steel before a plastic sheath is extruded over it for corrosion protection. This sheath forms an impervious moisture barrier. Metallplastic sheath with a
20、 welded-steel tape 3.4.2.5 This type of sheath includes as the impervious layer an extruded lead sheath. To protect the cable core from the lead extrusion temperature, a suitable heat barrier layer between core and lead sheath is necessary. MeWpIastic sheath with an extruded lead sheath 3.43 Plastic
21、 sheath only This type of sheath is extruded from plastic matenal (PE or PVC etc.) and is not moisture resistant. 3.4.4 This sheath design contains longitudinal or crossply strength members which may be metallic or non-metallic. Plastic sheath with strengb members 3.4.4.1 This type of sheath has hel
22、ically wound strength members in two torsionally balanced layers in opposite directions with a plastic sheath extruded over them. The strength members can be made of either steel of fibreglass reinforced Plasc sheath with cM)GspIy strength members plastic (FRP). 18 chap. I 3.4.4.2 This type of sheat
23、h has generally aramid strength members and may also include glass fibre srrength members bonded to the cable sheath. With aramid strength members in the sheath construction it may be necessary to inoduce an antibuckling central strength member. The sheath may contain a moisture barrier as described
24、 in 5 3.4.4.1. Plastic sheath with bonded strength members 3.4.5 This type of cable sheath has two parallel, steel strength members embedded in the plastic sheath which is extruded over a corrugated steel tape. The steel tape is placed over the core and provides a moisture barrier as discussed above
25、 in 9 3.4.2.2. Plastic sheath with embedded strength members with a metallic tape 3.4.6 Cable sheath with amour A number of armour oversheahs are used for added protection to the optical cable to meet particular environmental conditions. An example of where additional protection is applied to the ca
26、ble sheath is for lake and river crossings to resist water current and snagging. One or more helically applied layers of zinc coated steel or stainless steel wires may be applied to the sheath and protected with layers of compound, twine bedding and wrapping or layers of compound and an extruded pla
27、stic sheath. Caution: generation of hydrogen due to corrosion must be considered when selecting the armour wires. A copper tape may be applied as anti-teredo protection. A lead oversheath may be applied over the plastic sheath in areas of severe or extensive exposure to petrochemicals. As a protecti
28、on against rodents a meWplastic bonded sheath with a corrugated steel or stainless steel tape coated on both sides may be applied over the sheath. 4 Fibre and Cable Tests 4.1 Optical transmission characteristics and test methods for multimode fibres are given in lTlJ-T Recommendation G.65 1. Optical
29、 transmission characteristics for single-mode fibres are given in ITU-T Recommendations G.652, G.653 and G.654, and the test methods are given in iT-T Recommendation G.650. Optical Transmission Characteristics of Fibres 4.2 The dimensional characteristics and test methods for multimode fibres are gi
30、ven in ITU-T Recommendation G.651. The dimensional characteristics for single-mode fibres are given in ITU-T Recommendations G.652, G.653, and G.654, and the test methods are given in ITU-T Recommendation G.650. Methods for measuring the dimensions of optical fibre cables are given in 0 2 of EC Publ
31、ication 794-1. Dimensional Characteristics of Fibres and Optical Cables 4.3 Methds for measuring the mechanical charactenstics of optical cables are given in Q 3 of IEC Publication 794- 1. Mechanical Characteristics of Optical Cables References Griffin A. A. “The phenomena of rupture and flaws in so
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33、D. “Curvature loss formula for optical fibres”. J. Opt. Soc. Am. 66 No. 3, pp. 216-220, 1976. Uesugi N. et. al. “Infrared optical loss increase for silica fibre in cable filled with water.” Electronic Letters, September 15, 1983. Kalish D., Tariyal B. K., Chandan H. C. “Effect of moisture on the str
34、ength of optical fibres”. Proceedings of the 27th International Wire and Cable Symposium. Cherry Hill, p. 331, November, 1986. Gardner W.B. “Microbending loss in optical fibres”. Bell Syst. Tech. Jour. 54 No. 2, pp. 457465, 1975. Chp. I 19 m 4862593 0678864 34T 171 181 191 Beaies K. J. e?. al. “Incr
35、eased attenuation in optical fibres caused by difision of molecular hydrogen at room temperature”. Electronic Letters Vol. 19, pp. 917-919. 1983. Itoh H. e?. al. “Chemical change from diffused hydrogen gas to hydroxyl ion in silica glass optical fibres”. Electronic Letters Vol. 20, pp. 140-142,1984.
36、 Pitt N. J., Marshall A. “Long term loss stability of single-mode optical fibres exposed to hydrogen”. Electronic Letters Vol. 20, pp. 512-514, 1984. Wang T.T., Zupko H.M., “Long term mechanical behaviour of optical fibres coated with UV curable epoxy acrylate”. Jour Material Science 13, p. 2241,197
37、8. Yamanishi T. er. al. “Modified silicon as new type of primary coat for optical fibre”. Electronic Letters 16, p. 100,1980. Haag H. G. er. al. “High density opticai fibre cables for the local network”. Proc. of the 30th International Wire and Cable Symposium pp. 259-269 198 1. Gartside C. H. et.al
38、. A single-mode lightguide cable design for long haul transmission”. 9th European Conf. on ptical Communication, pp. 223-226.1983. DeVecchis M Hulin J. P., Le Noane G. “Experimental results of cylindrical V-groove structure optical cables laid in duct and spliced”. 4th Conf. Eur., Genoa, 1978. Ishih
39、ar K. et. al. Determimiion of optimum structure in coated optical fibre and cable unit”. 5th Eur. Conf. on Opt. Communication 7.3, 1979. Nakahara T., Uchida N. “Optical cable design and characterization in Japan”. Proc. EEE Vol. 68, pp. 1220-1226, 1980. Szentest Otto 1. “Reliability of optical fibres, cables, and splices”. IEEE Journal on Selected Areas in Communication Vol. SAC-4 No. 9, December, 1986. 20 chap. I
