SANS 62221-2002 Optical fibres - Measurement methods - Microbending sensitivity《光纤 测量方法 微弯敏感性》.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ICS 33.180.01 ISBN 0-626-13984-8 SANS 62221:2002 Edition 1 IEC TR 62221:2001 Edition 1 SOUTH AFRICAN NATIONAL STANDARD Optical fibres Measurement methods

4、 Microbending sensitivity This national standard is the identical implementation of IEC 62221:2001 and is adopted with the permission of the International Electrotechnical Commission. Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fa

5、x: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa 2002 SANS 62221:2002 Edition 1 IEC TR 62221:2001 Edition 1 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee STANSA SC 74A, Fibre optics, in accord

6、ance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. RAPPORTTECHNIQUECEIIECTECHNICALREPORTTR 62221Premire ditionFirst edition2001-10Fibres optiques Mthodes de mesure Sensibilit aux microcourburesOptical fibres Measurement methods Microbending sensitivi

7、tyCommission Electrotechnique InternationaleInternational Electrotechnical CommissionPour prix, voir catalogue en vigueurFor price, see current catalogue IEC 2001 Droits de reproduction rservs Copyright - all rights reservedAucune partie de cette publication ne peut tre reproduite niutilise sous que

8、lque forme que ce soit et par aucun procd,lectronique ou mcanique, y compris la photocopie et lesmicrofilms, sans laccord crit de lditeur.No part of this publication may be reproduced or utilized inany form or by any means, electronic or mechanical,including photocopying and microfilm, without permi

9、ssion inwriting from the publisher.International Electrotechnical Commission 3, rue de Varemb Geneva, SwitzerlandTelefax: +41 22 919 0300 e-mail: inmailiec.ch IEC web site http:/www.iec.chCODE PRIXPRICE CODE LThis page is intentionally left blankTR 62221 IEC:2001 3 CONTENTSFOREWORD.51 Scope and obje

10、ct72 Reference documents.73 Test procedures .93.1 Method A: expandable drum93.1.1 General .93.1.2 Apparatus93.1.3 Procedure93.1.4 Calculations.93.1.5 Results 113.2 Method B: fixed diameter drum113.2.1 General .113.2.2 Apparatus113.2.3 Procedure133.2.4 Calculations.133.2.5 Results 133.3 Method C: wir

11、e mesh.133.3.1 General .133.3.2 Apparatus133.3.3 Procedure173.3.4 Calculations.173.3.5 Results 193.4 Method D: basketweave 193.4.1 General .193.4.2 Apparatus193.4.3 Procedure213.4.4 Calculations or interpretation of results233.4.5 Results 23Figure 1 Microbending inducing equipment. .15Figure 2 Quart

12、z drum.10Figure 3 Temperature cycle inside chamber.23TR 62221 IEC:2001 5 INTERNATIONAL ELECTROTECHNICAL COMMISSION_OPTICAL FIBRES MEASUREMENT METHODS MICROBENDING SENSITIVITYFOREWORD1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprisingall n

13、ational electrotechnical committees (IEC National Committees). The object of the IEC is to promoteinternational co-operation on all questions concerning standardization in the electrical and electronic fields. Tothis end and in addition to other activities, the IEC publishes International Standards.

14、 Their preparation isentrusted to technical committees; any IEC National Committee interested in the subject dealt with mayparticipate in this preparatory work. International, governmental and non-governmental organizations liaisingwith the IEC also participate in this preparation. The IEC collabora

15、tes closely with the InternationalOrganization for Standardization (ISO) in accordance with conditions determined by agreement between thetwo organizations.2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, aninternational consensus of opinion on th

16、e relevant subjects since each technical committee has representationfrom all interested National Committees.3) The documents produced have the form of recommendations for international use and are published in the formof standards, technical specifications, technical reports or guides and they are

17、accepted by the NationalCommittees in that sense.4) In order to promote international unification, IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards. Anydivergence between the IEC Standard and t

18、he corresponding national or regional standard is clearly indicatedin the latter.5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment declared to be in conformity with one of its standards.6) Attention is drawn to the possibility that

19、some of the elements of this technical report may be the subject ofpatent rights. The IEC is not held responsible for identifying any or all such patent rights.The main task of IEC technical committees is to prepare International Standards. However, atechnical committee may propose the publication o

20、f a technical report when it has collecteddata of a different kind from that which is normally published as an International Standard, forexample “state of the art“.IEC 62221, which is a technical report, has been prepared by subcommittee 86A: Fibres andcables, of IEC technical committee 86: Fibre o

21、ptics.The text of this technical report is based on the following documents:Enquiry draft Report on voting86A/652/CDV 86A/721/RVCFull information on the voting for the approval of this technical report can be found in thereport on voting indicated in the above table.This publication has been drafted

22、 in accordance with the ISO/IEC Directives, Part 3.The committee has decided that the contents of this publication will remain unchanged until2004. At this date, the publication will be reconfirmed; withdrawn; replaced by a revised edition, or amended.This document, which is purely informative, is n

23、ot to be regarded as an International Standard.TR 62221 IEC:2001 7 OPTICAL FIBRES MEASUREMENT METHODS MICROBENDING SENSITIVITY1 Scope and objectThis technical report describes four techniques for the measurement of microbendingsensitivity of optical fibre.Methods A and B may also be used to measure

24、the microbending sensitivity of optical fibreribbons.Methods A, B, C and D are distinguished by the equipment used for measurements and theirapplications: method A uses an expandable drum and applies to class B fibres; method B uses a fixed diameter drum and applies to category A1 and class B fibres

25、; method C uses a wire mesh and applied loads and applies to category A1 and class Bfibres; method D uses a “basketweave“ wrap on a fixed diameter drum, and applies to class Bfibres.Methods A and C offer the capability to measure the microbending sensitivity over a widerange of applied linear pressu

26、re or loads. Method B may be used to determine themicrobending sensitivity for a fixed linear pressure.The results from the four methods can only be compared qualitatively.These methods do not constitute a routine test used in the general evaluation of optical fibre.This parameter is not generally s

27、pecified within a detail specification.2 Reference documentsNOTE The following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenced document(including any amendme

28、nts) applies.IEC 60793-1-1:1995, Optical fibres Part 1-1: Generic specification GeneralIEC 60793-1-22:2001, Optical fibres Part 1-22: Measurement methods and test procedures Length measurementIEC 60793-1-40:2001, Optical fibres Part 1-40: Measurement methods and test procedures AttenuationIEC 60793-

29、1-46:2001, Optical fibres Part 1-46: Measurement and test procedures Monitoring of changes in optical transmittanceTR 62221 IEC:2001 9 3 Test procedures3.1 Method A: expandable drum3.1.1 GeneralThis subclause describes a technique for the measurement of the loss increase due tomicrobending effects i

30、nduced by the application of linear pressure to a single-mode opticalfibre. This method may also be used to measure the microbending sensitivity of optical fibreribbons.3.1.2 ApparatusThe apparatus is an expandable drum, the diameter of which can be changed continuously. Inorder to avoid any loss co

31、ntribution due to macrobending effects, a minimum drum diameterof 200 mm is recommended. The curvature at any edges of the expanded segments of thedrum also exceeds 200 mm diameter. The drum surface is coated with a material of fixedroughness, e.g. a sandpaper/lapping film PSA grade 40 m mineral Al2

32、O3. It is possible towind at least 400 m of the fibre or ribbon to be tested onto the rough surface. The windingpitch is controlled to prevent the fibre/ribbon turns from overlapping.While expanding the drum, the fibre elongation is measured using the phase-shift method(Method E of IEC 60793-1-22).

33、The attenuation measurement is conducted using either thecut-back technique (method A of IEC 60793-1-40), the backscatter technique (method C ofIEC 60793-1-40) or by the direct transmitted power measurement technique (method A ofIEC 60793-1-46).3.1.3 ProcedureThe fibre to be tested is carefully woun

34、d onto the coated drum with minimal tension (e.g. 40 gto 50 g) in one single layer avoiding any crossing or overlapping. The fibre is fixed to avoidany relative slipping. While expanding the drum the changes in attenuation coefficient andphase are recorded.3.1.4 Calculations.The fibre elongation ( )

35、 can be found from: = VLf(1)where is the phase shift (degrees);f is the modulation frequency (Hz);L is the length of the sample (km);V is the constant depending on the photo-elastic coefficient (k), of the speed of light in avacuum (c) and the group index (N):V = Nck360(2)For category B1 fibres, V i

36、s typically 726 km/s/degree.TR 62221 IEC:2001 11 From this the linear pressure P can be calculated:P = RT= REA(3)whereT is the tension applied to the fibre (N);R is the radius of the expandable drum in rest condition (mm);E is the Youngs modulus of the fibre (N/mm2);A is the cross-sectional area of

37、the fibre (glass part) (mm2).The changes in attenuation coefficient (dB/km) are plotted as a function of the linear pressureP (N/mm) or the elongation (%). The points obtained are interpolated by a straight linepassing through the origin, the slope of which gives the microbending sensitivity (dB/km)

38、/(N/mm) or (dB/km/%) of the tested fibre.3.1.5 ResultsThe following information should be reported for each test: test apparatus arrangement; minimum diameter of the expandable drum; roughness and type of material used to cover the drum; fibre identification; length of fibre wound onto the expandabl

39、e drum; wavelength of optical source; plot of measured change in attenuation coefficient as a function of the calculated linearpressure or of the elongation; microbending sensitivity (dB/km)/(N/mm) or (dB/km/%); relative humidity and ambient temperature during the test.3.2 Method B: fixed diameter d

40、rum3.2.1 GeneralThis subclause describes a procedure to measure the microbending sensitivity of category A1and class B fibres. This technique gives the loss increase due to microbending effects for afixed linear pressure applied to the fibre. This method may also be used to measure themicrobending s

41、ensitivity of optical fibre ribbons.3.2.2 Apparatus.The apparatus consists of a fixed diameter drum. In order to avoid macrobending effects theminimum drum diameter is 200 mm.The surface of the drum is coated with a material of fixed roughness (for example: sandpaper lapping film PSA grade 40 m mine

42、ral Al2O3). It is possible to wind at least 400 m of thefibre/ribbon to be tested onto the coated surface of the drum.The attenuation measurement is performed using the cut-back technique (method A ofIEC 60793-1-40) or by the backscatter technique (method C of IEC 60793-1-40). TR 62221 IEC:2001 13 3

43、.2.3 ProcedureThe fibre to be tested is wound onto the coated surface of the drum in one single layer, i.e.avoiding crossovers. The winding tension is 3 N.Measure the attenuation coefficient of the fibre under test. Calculate the attenuation increasedue to microbending by subtracting the intrinsic a

44、ttenuation coefficient of the fibre.3.2.4 CalculationsThe microbending sensitivity is found from the following relationship:Microbending sensitivity = TR= P(dB/km)/(N/mm) (4)where is the attenuation increase due to the microbending sensitivity (dB/km);P is the linear pressure (N/mm), see equation (3

45、);R is the radius of the fixed drum (mm);T is the winding tension applied to the fibre (N).The complete procedure may be repeated using different winding forces.3.2.5 ResultsThe following information should be reported for each test: date of test; test apparatus arrangement; diameter of drum; roughn

46、ess and type of material used; fibre identification; length of fibre wound onto the coated surface of the drum; wavelength of the optical source; microbending sensitivity (dB/km)/(N/mm).3.3 Method C: wire mesh3.3.1 GeneralThis subclause describes a procedure to measure the microbending sensitivity o

47、f category A1and class B fibres. This technique gives the loss increase due to microbending effects causedby the application of a wire mesh (under load) to the fibre under test.3.3.2 ApparatusThe apparatus comprises: the microbend inducing equipment is shown in figure 1.TR 62221 IEC:2001 15 Top plat

48、eWire meshBase to support the meshincluding post to alignthe top plateVulcanised rubberFibre under testIEC 1596/01Figure 1 Microbend-inducing equipment3.3.2.1 Microbend-inducing equipmentAn arrangement as shown in figure 1 is used to produce the microbend losses. The metalbase plate acts as a locati

49、on and smooth surface for the upper layers of the equipment. Usedowels or other devices to both align the plates and allow the top plate to compress onto thelower plate.It is critical that all the surfaces should be flat and smooth so that the load is borne only bythe fibre. This can also be facilitated by reducing the surfaces to an area as small as possible whilst still covering the fibre.A sheet of vulcanised rubber, having a