EN 61746:2001

EUROPEAN STANDARD EN 61746
NORME EUROPÉENNE
EUROPÄISCHE NORM November 2001
ICS 17.180.30;33.180.99
English version
Calibration of optical time-domain reflectometers (OTDRs)
(IEC 61746:2001)
Etalonnage des réflectomètres optiques Kalibrierung optischer
dans le domaine de temps (OTDR) Rückstreumessgeräte (OTDR)
(CEI 61746:2001) (IEC 61746:2001)
This European Standard was approved by CENELEC on 2001-10-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61746:2001 E
Foreword
The text of document 86/175/FDIS, future edition 1 of IEC 61746, prepared by IEC TC 86, Fibre
optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61746 on 2001-10-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2002-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2004-10-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes A, B, C and ZA are normative and annex D is informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61746:2001 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 61746:2001
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-731 1991 International Electrotechnical --
Vocabulary (IEV)
Chapter 731: Optical fibre
communication
IEC 60617-10 1996 Graphical symbols for diagrams EN 60617-10 1996
Part 10: Telecommunications:
Transmission
IEC 60793-1 Series Optical fibres --
Part 1: Generic specification
IEC 60794-1 Series Optical fibre cables EN 60794-1 Series
Part 1: Generic specification
IEC 60825-1 1993 Safety of laser products EN 60825-1 1994
Part 1: Equipment classification, + corr. February 1995
requirements and user's guide + A11 1996
A1 1997 - -
A2 2001 A2 2001
IEC 61300-3-2 1999 Fibre optic interconnecting devices and EN 61300-3-2 1999
passive components - Basic tests and
measurement procedures
Part 3-2: Examinations and
measurements - Polarization
dependence of attenuation in a single-
mode fibre optic device
ISO 1993 International vocabulary of basic and--
general terms in metrology
ISO 1995 Guide to the expression of uncertainty--
in measurement
ITU-T 1997 Definition and test methods for the--
Recommendation relevant parameters of single-mode
G.650 fibres
NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Première édition
STANDARD
First edition
2001-09
Etalonnage des réflectomètres optiques
dans le domaine de temps (OTDR)
Calibration of optical time-domain
reflectometers (OTDRs)
© IEC 2001 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
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61746 © IEC:2001 – 3 –
CONTENTS
FOREWORD . 9
1 General. 11
1.1 Scope . 11
1.2 Normative references. 11
2 Definitions. 13
3 Calibration test requirements. 23
3.1 Preparation . 23
3.2 Test conditions. 23
3.3 Traceability . 23
4 Distance calibration – General. 25
4.1 Location error model . 25
4.2 Using the calibration results . 29
4.3 Measuring fibre length. 29
5 Distance calibration methods. 31
5.1 External source method . 31
5.1.1 Short description and advantage. 31
5.1.2 Equipment. 31
5.1.3 Measurement procedure. 35
5.1.4 Calculations and results . 37
5.1.5 Uncertainties. 37
5.2 Concatenated fibre method . 41
5.2.1 Short description and advantages. 41
5.2.2 Equipment. 41
5.2.3 Measurement procedures . 43
5.2.4 Calculations and results . 45
5.2.5 Uncertainties. 47
5.3 Recirculating delay line method . 49
5.3.1 Short description and advantage. 49
5.3.2 Equipment. 49
5.3.3 Measurement procedures . 51
5.3.4 Calculations and results . 53
5.3.5 Uncertainties. 53
6 Loss calibration – General. 57
6.1 Determination of the displayed power level F . 57
6.2 Selection of an appropriate reference loss A . 59
ref
6.3 Development of a test plan. 59
6.4 Polarization dependence . 63
6.5 Calculation of the calibration results . 65
6.6 Using the calibration results . 67

61746 © IEC:2001 – 5 –
7 Loss calibration methods. 67
7.1 Loss calibration with fibre standard. 67
7.1.1 Short description and advantage. 67
7.1.2 Equipment. 67
7.1.3 Measurement procedure. 71
7.1.4 Calculations and results . 71
7.1.5 Uncertainties. 73
7.2 External source method . 75
7.2.1 Short description and advantage. 75
7.2.2 Equipment. 75
7.2.3 Measurement procedure. 77
7.2.4 Calculations and results . 79
7.2.5 Uncertainties. 81
7.3 Splice simulator method . 81
7.3.1 Short description and advantage. 81
7.3.2 Equipment. 83
7.3.3 Procedure . 85
7.3.4 Calculations and results . 87
7.3.5 Uncertainties. 89
7.4 Power reduction method. 89
7.4.1 Short description and advantage. 89
7.4.2 Equipment. 91
7.4.3 Measurement procedure. 95
7.4.4 Calculations and results . 95
7.4.5 Uncertainties. 95
8 Reflectance calibration . 97
9 Documentation. 97
9.1 Measurement data and uncertainties . 97
9.2 Test conditions. 99
Annex A (normative) Recirculating delay line for distance calibration. 101
A.1 Construction . 101
A.2 Calibration . 101
A.3 Uncertainties. 105
A.4 Documentation. 107
Annex B (normative) Optical fibre standard for loss calibration . 109
B.1 Fibre requirements. 109
B.2 Suitability check of the fibre. 109
B.3 Preparation and calibration of the fibre standard. 113
B.4 Recalibration of the optical fibre standard.
...