IEC 61746-1:2009

Calibration of optical time-domain reflectometers (OTDR) - Part 1: OTDR for single mode fibres

IEC 61746-1: 2009 provides procedures for calibrating single-mode optical time domain reflectometers (OTDR). It only covers OTDR measurement errors and uncertainties. This standard does not cover correction of the OTDR response. This first edition of IEC 61746-1 cancels and replaces the second edition of IEC 61746, published in 2005. It constitutes a technical revision. The main technical changes are the adaptation of Clause 4, the suppression of Clause 10, the improvement and the addition of some definitions, the change of some calculations and the change of graphical symbology to IEC/TR 61930. Keywords: calibrating single-mode optical time domain reflectometers (OTDR)

Etalonnage des réflectomètres optiques dans le domaine temporel (OTDR) - Partie 1: OTDR pour fibres unimodales

L'IEC 61746-1:2009 fournit des procédures destinées à l'étalonnage des réflectomètres optiques dans le domaine de temps pour fibres unimodales (OTDR). Elle ne traite que des erreurs de mesure et incertitudes de l'OTDR. Cette norme ne couvre pas la correction de la réponse de l'OTDR. Cette première édition de la CEI 61746-1 annule et remplace la deuxième édition de la CEI 61746, publiée en 2005. Elle constitue une révision technique. Les principales modifications techniques sont l'adaptation de l'article 4, la suppression de l'article 10, l'amélioration et l'ajout de certaines définitions, le changement de certains calculs et le changement de symbologie graphique IEC / TR 61930. Mots clés : l'étalonnage des réflectomètres optiques dans le domaine de temps pour fibres unimodales (OTDR)

General Information

• Status: Published
• Publication Date: 16-Dec-2009
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.180.01 - Fibre optic systems in general
• Technical Committee: TC 86 - Fibre optics
• Drafting Committee: WG 4 - TC 86/WG 4
• Current Stage: PPUB - Publication issued
• Start Date: 15-Jan-2010
• Completion Date: 17-Dec-2009

Relations

• Replaces: IEC 61746:2005 - Calibration of optical time-domain reflectometers (OTDR)
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61746-1 ®
Edition 1.0 2009-12
INTERNATIONAL
STANDARD
Calibration of optical time-domain reflectometers (OTDR) –
Part 1: OTDR for single mode fibres

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
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IEC 61746-1 ®
Edition 1.0 2009-12
INTERNATIONAL
STANDARD
Calibration of optical time-domain reflectometers (OTDR) –
Part 1: OTDR for single mode fibres

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XC
ICS 33.180.01 ISBN 978-2-88910-553-3
– 2 – 61746-1 © IEC:2009(E)
CONTENTS
FOREWORD.6
INTRODUCTION.8
1 Scope.9
2 Normative references.9
3 Terms, definitions and symbols .9
4 Preparation for calibration.16
4.1 Organization .16
4.2 Traceability.16
4.3 Preparation.16
4.4 Test conditions .16
4.5 Documentation .16
5 Distance calibration – General .17
5.1 General .17
5.2 Location deviation model .17
5.3 Using the calibration results.19
5.4 Measuring fibre length .19
6 Distance calibration methods .20
6.1 General .20
6.2 External source method .20
6.2.1 Short description and advantage .20
6.2.2 Equipment .20
6.2.3 Calibration of the equipment .21
6.2.4 Measurement procedure .22
6.2.5 Calculations and results .23
6.2.6 Uncertainties .24
6.3 Concatenated fibre method.25
6.3.1 Short description and advantages .25
6.3.2 Equipment .25
6.3.3 Measurement procedures.27
6.3.4 Calculations and results .27
6.3.5 Uncertainties .28
6.4 Recirculating delay line method.29
6.4.1 Short description and advantage .29
6.4.2 Equipment .29
6.4.3 Measurement procedure .31
6.4.4 Calculations and results .31
6.4.5 Uncertainties .32
7 Loss calibration – General .33
7.1 General .33
7.2 Determination of the displayed power level F .33
7.3 Selection of an appropriate reference loss A .34
ref
7.4 Development of a test plan .35
7.5 Polarization dependence.37
7.6 Calculation of the calibration results.38
7.7 Using the calibration results.38
8 Loss calibration methods .38

61746-1 © IEC:2009(E) – 3 –
8.1 General .38
8.2 Fibre standard method.39
8.2.1 Short description and advantage .39
8.2.2 Equipment .39
8.2.3 Measurement procedure .40
8.2.4 Calculations and results .41
8.2.5 Uncertainties .41
8.3 External source method (see Figure 16).42
8.3.1 Short description and advantage .42
8.3.2 Equipment .42
8.3.3 Calibration of the reference loss.43
8.3.4 Measurement procedure .44
8.3.5 Calculations and results .45
8.3.6 Uncertainties .45
8.4 Splice simulator method.46
8.4.1 Short description and advantage .46
8.4.2 Equipment .46
8.4.3 Procedure.47
8.4.4 Calculations and results .49
8.4.5 Uncertainties .49
8.5 Power reduction method .50
8.5.1 Short description and advantage .50
8.5.2 Equipment .51
8.5.3 Measurement procedure .52
8.5.4 Calculations and results .53
8.5.5 Uncertainties .53
9 Reflectance calibration.54
9.1 Objective .54
9.2 Reflectance measurements (see Figure 23) .54
9.3 Use of the backscatter parameter, K .54
9.4 Range of reflectance measurement.55
9.5 Development of a test plan .56
9.6 Equipment .57
9.7 Measurement procedure .58
9.7.1 Preparation.58
9.7.2 Taking reflectance measurements.58
9.7.3 Calculation and results.58
9.7.4 Uncertainties .58
Annex A (normative) Recirculating delay line for distance calibration .60
Annex B (normative) Optical fibre standard for loss calibration.64
Annex C (normative) Standard splice simulator for loss calibration.68
Annex D (normative) Mathematical basis.72
Annex E (normative)  Reflectance standard .75
Annex F (normative)  Simple version of reflectance standard.81
Annex G (informative)  OTDR basis: Backscatter theory – Reflectance measurements
using an OTDR – Determination of fibre backscatter parameter .85
Bibliography .90

– 4 – 61746-1 © IEC:2009(E)
Figure 1 – Definition of attenuation dead zone .10
Figure 2 – Representation of the location deviation ΔL(L).18
Figure 3 – Equipment for calibration of the distance scale – External source method .21
Figure 4 – Set-up for calibrating the system insertion delay.22
Figure 5 – Concatenated fibres used for calibration of the distance scale.26
Figure 6 – Distance calibration with a recirculating delay line .30
Figure 7 – OTDR trace produced by recirculating delay line .30
Figure 8 – Determining the reference level and the displayed power level .34
Figure 9 – Measurement of the OTDR loss samples .
...

IEC 61746-1 ®
Edition 1.0 2009-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Calibration of optical time-domain reflectometers (OTDR) –
Part 1: OTDR for single mode fibres

Étalonnage des réflectomètres optiques dans le domaine temporel (OTDR) –
Partie 1 : OTDR pour fibres unimodales

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 IEC's 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.

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The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

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IEC 61746-1 ®
Edition 1.0 2009-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Calibration of optical time-domain reflectometers (OTDR) –

Part 1: OTDR for single mode fibres

Étalonnage des réflectomètres optiques dans le domaine temporel (OTDR) –

Partie 1 : OTDR pour fibres unimodales

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XC
ICS 33.180.01 ISBN 978-2-8322-1682-8

– 2 – IEC 61746-1:2009 © IEC 2009
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references. 9
3 Terms, definitions and symbols . 9
4 Preparation for calibration . 16
4.1 Organization . 16
4.2 Traceability . 16
4.3 Preparation . 16
4.4 Test conditions . 16
4.5 Documentation . 16
5 Distance calibration – General . 17
5.1 General . 17
5.2 Location deviation model . 17
5.3 Using the calibration results . 19
5.4 Measuring fibre length . 19
6 Distance calibration methods . 20
6.1 General . 20
6.2 External source method . 20
6.2.1 Short description and advantage . 20
6.2.2 Equipment . 20
6.2.3 Calibration of the equipment . 21
6.2.4 Measurement procedure . 22
6.2.5 Calculations and results . 23
6.2.6 Uncertainties . 24
6.3 Concatenated fibre method . 25
6.3.1 Short description and advantages . 25
6.3.2 Equipment . 25
6.3.3 Measurement procedures. 27
6.3.4 Calculations and results . 27
6.3.5 Uncertainties . 28
6.4 Recirculating delay line method . 29
6.4.1 Short description and advantage . 29
6.4.2 Equipment . 29
6.4.3 Measurement procedure . 31
6.4.4 Calculations and results . 31
6.4.5 Uncertainties . 32
7 Loss calibration – General . 33
7.1 General . 33
7.2 Determination of the displayed power level F . 33
7.3 Selection of an appropriate reference loss A . 34
ref
7.4 Development of a test plan . 35
7.5 Polarization dependence . 37
7.6 Calculation of the calibration results . 38
7.7 Using the calibration results . 38

8 Loss calibration methods . 38
8.1 General . 38
8.2 Fibre standard method . 39
8.2.1 Short description and advantage . 39
8.2.2 Equipment . 39
8.2.3 Measurement procedure . 40
8.2.4 Calculations and results . 41
8.2.5 Uncertainties . 41
8.3 External source method (see Figure 16) . 42
8.3.1 Short description and advantage . 42
8.3.2 Equipment . 42
8.3.3 Calibration of the reference loss . 43
8.3.4 Measurement procedure . 44
8.3.5 Calculations and results . 45
8.3.6 Uncertainties . 45
8.4 Splice simulator method . 46
8.4.1 Short description and advantage . 46
8.4.2 Equipment . 46
8.4.3 Procedure . 47
8.4.4 Calculations and results . 49
8.4.5 Uncertainties . 49
8.5 Power reduction method . 50
8.5.1 Short description and advantage .
...