1、 IEC/TR 62221 Edition 2.0 2012-12 TECHNICAL REPORT Optical fibres Measurement methods Microbending sensitivity IEC/TR 62221:2012(E) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2012 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publicati
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9、ECTROTECHNICAL COMMISSION T ICS 33.180.10 PRICE CODE ISBN 978-2-83220-500-6 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. colour inside 2 TR 62221 IEC:2012(E) CONTENTS FOREWORD . 4 1 Scope .
10、 6 2 Normative references . 6 3 General properties of microbending loss . 7 4 General considerations . 7 Launch condition for multimode fibres . 7 4.1Sample lengths . 7 4.2Winding tension . 7 4.3Relaxation time . 8 4.4Material used for fixed roughness 8 4.5Drum materials 8 4.6Drum material for tempe
11、rature cycling . 8 4.7 5 Test procedures . 8 Method A: expandable drum 8 5.1General . 8 5.1.1Apparatus 8 5.1.2Procedure 9 5.1.3Calculations . 9 5.1.4Method B: fixed diameter drum 10 5.2General . 10 5.2.1Apparatus 10 5.2.2Procedure 12 5.2.3Calculations . 12 5.2.4Method C: plate test 13 5.3General . 1
12、3 5.3.1Apparatus 13 5.3.2Procedure 14 5.3.3Calculations . 14 5.3.4Method D: basketweave 15 5.4General . 15 5.4.1Apparatus 15 5.4.2Procedure 16 5.4.3Calculations or interpretation of results 17 5.4.4 6 Results . 17 Annex A (informative) Representative results with method B 19 Bibliography 24 Figure 1
13、 Set-up for expandable drum method used in an optical fibre testing facility . 9 Figure 2 Standard winding/prooftester can be used for preparing the sample . 11 Figure 3 Example of a possible set-up in temperature cycling . 11 Figure 4 Alternative wire mesh set-up used in an optical fibre testing fa
14、cility 12 Figure 5 Microbend-inducing equipment . 13 Figure 6 Quartz drum with basketwoven fibre . 15 TR 62221 IEC:2012(E) 3 Figure 7 Basketweave example as used in an optical fibre testing facility 16 Figure 8 Example of temperature cycle inside chamber 17 Figure A.1 Example of temperature cycling
15、of 10 different unshifted single-mode fibres (wavelength 1 310 nm) 20 Figure A.2 Example of temperature cycling of 10 different unshifted single-mode fibres (wavelength 1 550 nm) 20 Figure A.3 Microbending repeatability for fibre N 1 with winding tension 1 N . 21 Figure A.4 Ribbon set-up . 21 Figure
16、 A.5 Losses at 1 310 nm for different ribbons . 22 Figure A.6 Losses at 1 625 nm for different ribbons . 22 Table A.1 Used instrument and values for single-mode fibres 19 Table A.2 Multimode fibre test results 23 4 TR 62221 IEC:2012(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ OPTICAL FIBRES MEASU
17、REMENT METHODS MICROBENDING SENSITIVITY FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all que
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28、r, a technical committee may propose the publication of a technical report when it has collected data of a different kind from that which is normally published as an International Standard, for example “state of the art“. IEC 62221, which is a technical report, has been prepared by subcommittee 86A:
29、 Fibres and cables, of IEC technical committee 86: Fibre optics. This second edition cancels and replaces the first edition published in 2001, and constitutes a technical and editorial revision. The main changes with respect to the previous edition are listed below: a) updates related to B6 (bend-in
30、sensitive) category single-mode fibres; b) inclusion of a definition for microbending and general properties; c) expansion of general considerations; TR 62221 IEC:2012(E) 5 d) more details given for each method; e) addition of an Annex A. The text of this technical report is based on the following d
31、ocuments: Enquiry draft Report on voting 86A/1460/DTR 86A/1470/RVC Full information on the voting for the approval of this technical report can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The comm
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34、int this document using a colour printer. 6 TR 62221 IEC:2012(E) OPTICAL FIBRES MEASUREMENT METHODS MICROBENDING SENSITIVITY 1 Scope IEC 62221, which is a technical report, describes four methods (A, B, C and D) for the measurement of microbending sensitivity of optical fibres. These four methods ar
35、e distinguished by the equipment being used for measurements and their applications: method A using an expandable drum and applies to category A1 and class B fibres; method B using a fixed diameter drum and applies to category A1 and class B fibres; method C using a plate and applied loads and appli
36、es to category A1 and class B fibres; method D using a “basketweave“ wrap on a fixed diameter drum, and applies to category A1 and class B fibres Methods A and B may also be used to measure the microbending sensitivity of optical fibre ribbons. Methods A and C offer the capability to measure the mic
37、robending sensitivity over a wide range of applied linear pressure or loads. Method B may be used to determine the microbending sensitivity for a fixed linear pressure. Methods A, B and D can also be used at different temperatures (temperature cycling) provided special low thermal expansion material
38、s (e.g. quartz drums) are used. The results from the four methods can only be compared qualitatively. These methods are considered characterization type tests. It shall be understood that the microbend results from any method, could have significant variation between laboratories. These methods do n
39、ot constitute a routine test used in the general evaluation of optical fibre. This parameter is not generally specified within a detail specification. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its applic
40、ation. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60793-1-1:2008, Optical fibres Part 1-1: Measurement methods and test procedures General and guidance IEC 60793-1-22:2001, Optica
41、l fibres Part 1-22: Measurement methods and test procedures Length measurement IEC 60793-1-40:2001, Optical fibres Part 1-40: Measurement methods and test procedures Attenuation TR 62221 IEC:2012(E) 7 IEC 60793-1-46:2001, Optical fibres Part 1-46: Measurement and test procedures Monitoring of change
42、s in optical transmittance IEC 62614, Fibre optics Launch condition requirements for measuring multimode attenuation 3 General properties of microbending loss Added loss due to microbending occurs when localized lateral forces along the length of the fibre appear. These may be caused by manufacturin
43、g and installation strains, as well as dimensional variations in the cable materials due to temperature changes. Sensitivity to microbending is a function of the difference of refractive index of the core and the cladding, and diameters of the core and cladding. Coating structure and material proper
44、ty may also have an influence. The effect of microbending in single-mode fibres is increased optical loss at 1 310 nm, 1 550 nm and 1 625 nm wavelength ranges as opposed to macrobend effects in single-mode fibres that primarily is present in the longer wavelengths 1 550 nm and 1 625 nm. In category
45、A1 multimode fibres, microbending manifests itself in general nearly equally over a wide wavelength range (e.g. 850 nm 1 320 nm). To reduce microbending losses, the cable structure has to protect the optical fibres from lateral forces. Loose tube cable construction should be optimized to prevent buc
46、kling of the fibre in the tube during temperature changes leading to possible macrobending as well as microbending loss. Cable components such as the cable sheath and the strength member are important because they also help to reduce the microbending caused by the external mechanical forces on the c
47、able and by temperature changes. Microbending losses may also be introduced in aerial cables subjected to excessive elongation (e.g. heavy ice loading). 4 General considerations Launch condition for multimode fibres 4.1 Concerning multimode fibres, reference is made to the launching technique descri
48、bed in IEC 62614, as done for the macrobend test method. Sample lengths 4.2 This technical report lists several methods to evaluate microbend sensitivity for optical fibres. One key difference is the sample length requirements for the different methods. Though the exact sample lengths may vary, a li
49、st with lengths that have been typically used is given here below: Method Length A 300 m B 400 m C 2 m 3 m D 2,5 km Winding tension 4.3 When using methods A, B or D, the control of the winding tension should be mentioned and carried out with a calibrated device. Added loss due to microbending is reasonably linear over 8 TR 62221 IEC:2012(E) a winding tension range from 1 N to 3 N, but different winding tensions could yield different normal
