IEC_61746-2-2010.pdf

IEC 61746-2Edition 1.0 2010-06INTERNATIONAL STANDARD Calibration of optical time-domain reflectometers(OTDR)Part 2:OTDR for multimode fibres IEC 61746-2:2010(E)THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2010 IEC,Geneva,Switzerland All rights reserved.Unless otherwise specified,no part of this publication may be reproduced or utilized in any form or by any means,electronic or mechanical,including photocopying and microfilm,without permission in writing from either IEC or IECs member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,please contact the address below or your local IEC member National Committee for further information.IEC Central Office 3,rue de Varemb CH-1211 Geneva 20 Switzerland Email:inmailiec.ch Web:www.iec.ch About the IEC The International Electrotechnical Commission(IEC)is the leading global organization that prepares and publishes International Standards for all electrical,electronic and related technologies.About IEC publications The technical content of IEC publications is kept under constant review by the IEC.Please make sure that you have the latest edition,a corrigenda or an amendment might have been published.?Catalogue of IEC publications:www.iec.ch/searchpub The IEC on-line Catalogue enables you to search by a variety of criteria(reference number,text,technical committee,).It also gives information on projects,withdrawn and replaced publications.?IEC Just Published:www.iec.ch/online_news/justpub Stay up to date on all new IEC publications.Just Published details twice a month all new publications released.Available on-line and also by email.?Electropedia:www.electropedia.org The worlds leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions in English and French,with equivalent terms in additional languages.Also known as the International Electrotechnical Vocabulary online.?Customer Service Centre:www.iec.ch/webstore/custserv If you wish to give us your feedback on this publication or need further assistance,please visit the Customer Service Centre FAQ or contact us:Email:csciec.ch Tel.:+41 22 919 02 11 Fax:+41 22 919 03 00 IEC 61746-2Edition 1.0 2010-06INTERNATIONAL STANDARD Calibration of optical time-domain reflectometers(OTDR)Part 2:OTDR for multimode fibres INTERNATIONAL ELECTROTECHNICAL COMMISSION XICS 33.180.01 PRICE CODEISBN 978-2-88912-026-0 Registered trademark of the International Electrotechnical Commission 2 61746-2 IEC:2010(E)CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.7 2 Normative references.7 3 Terms,definitions and symbols.7 4 Preparation for calibration.13 4.1 Organization.13 4.2 Traceability.13 4.3 Preparation.13 4.4 Test conditions.13 4.5 Documentation.13 5 Distance calibration General.14 5.1 General.14 5.2 Location deviation model.14 5.3 Using the calibration results.16 5.4 Measuring fibre length.17 6 Distance calibration methods.17 6.1 General.17 6.2 External source method.17 6.2.1 Short description and advantage.17 6.2.2 Equipment.17 6.2.3 Calibration of the equipment.19 6.2.4 Measurement procedure.20 6.2.5 Calculations and results.20 6.2.6 Uncertainties.21 6.3 Concatenated fibre method(using multimode fibres).23 6.3.1 Short description and advantages.23 6.3.2 Equipment.23 6.3.3 Measurement procedures.24 6.3.4 Calculations and results.24 6.3.5 Uncertainties.25 6.4 Recirculating delay line method.26 6.4.1 Short description and advantages.26 6.4.2 Equipment.27 6.4.3 Measurement procedure.28 6.4.4 Calculations and results.28 6.4.5 Uncertainties.29 7 Vertical scale calibration General.30 7.1 General.30 7.2 Loss difference calibration.31 7.2.1 Determination of the displayed power level F.31 7.2.2 Development of a test plan.31 7.3 Characterization of the OTDR source near field.33 7.3.1 Objectives and references.33 7.3.2 Procedure.33 8 Loss difference calibration method.34 61746-2 IEC:2010(E)3 8.1 General.34 8.2 Long fibre method.34 8.2.1 Short description.34 8.2.2 Equipment.34 8.2.3 Measurement procedure.36 8.2.4 Calculation and results.36 Annex A(normative)Multimode recirculating delay line for distance calibration.37 Annex B(normative)Mathematical basis.41 Bibliography.44 Figure 1 Definition of attenuation dead zone.8 Figure 2 Representation of the location deviation L(L).15 Figure 3 Equipment for calibration of the distance scale External source method.18 Figure 4 Set-up for calibrating the system insertion delay.19 Figure 5 Concatenated fibres used for calibration of the distance scale.23 Figure 6 Distance calibration with a recirculating delay line.27 Figure 7 OTDR trace produced by recirculating delay line.28 Figure 8 Determining the reference level and the displayed power level.31 Figure 9 Region A,the recommended region for loss measurement samples.32 Figure 10 Possible placement of sample points within region A.33 Figure 11 Linearity measurement with a long fibre.35 Figure 1