IEC 61746-2:2010

Calibration of optical time-domain reflectometers (OTDR) - Part 2: OTDR for multimode fibres

IEC 61746-2:2010 provides procedures for calibrating multimode optical time domain reflectometers (OTDR). It covers OTDR measurement errors and uncertainties. The test of the laser(s) source modal condition is included as an optional measurement. This standard does not cover correction of the OTDR response. Keywords: calibrating multimode optical time domain reflectometers (OTDR)

Étalonnage des réflectomètres optiques dans le domaine temporel (OTDR) - Partie 2: OTDR pour fibres multimodales

L'IEC 61746-2:2010 fournit des procédures destinées à l'étalonnage des réflectomètres optiques dans le domaine de temps pour fibres multimodales (OTDR). Elle traite des erreurs de mesure et incertitudes de l'OTDR. L'essai des conditions modales des sources laser est une mesure facultative. La présente norme ne couvre pas la correction de la réponse de l'OTDR. Mots clés: l'étalonnage des réflectomètres optiques dans le domaine de temps pour fibres multimodales (OTDR).

General Information

• Status: Published
• Publication Date: 20-Jun-2010
• 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: 30-Sep-2010
• Completion Date: 21-Jun-2010

Standards Content (Sample)

IEC 61746-2 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
Calibration of optical time-domain reflectometers (OTDR) –
Part 2: OTDR for multimode 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
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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IEC 61746-2 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
Calibration of optical time-domain reflectometers (OTDR) –
Part 2: OTDR for multimode fibres

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
X
ICS 33.180.01 ISBN 978-2-88912-026-0
– 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 ΔL(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 12 – Placing the beginning of section D outside the attenuation dead zone .35
Figure A.1 – Recirculating delay line.37
Figure A.2 – Measurement set-up for loop transit time T .38
b
Figure A.3 – Calibration set-up for lead-in transit time T .39
a
Table 1 – Additional distance uncertainty.16
Table 2 – Attenuation coefficients defining region A.32

– 4 – 61746-2 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CALIBRATION OF OPTICAL TIME-DOMAIN
REFLECTOMETERS (OTDR) –
Part 2: OTDR for multimode fibres

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International Standard IEC 61746-2 has been
...

IEC 61746-2 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Calibration of optical time-domain reflectometers (OTDR) –
Part 2: OTDR for multimode fibres

Étalonnage des réflectomètres optiques dans le domaine temporel (OTDR) –
Partie 2: OTDR pour fibres multimodales

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
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International Standards for all electrical, electronic and related technologies.

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IEC 61746-2 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Calibration of optical time-domain reflectometers (OTDR) –

Part 2: OTDR for multimode fibres

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

Partie 2: OTDR pour fibres multimodales

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.01 ISBN 978-2-8322-3067-1

– 2 – IEC 61746-2:2010  IEC 2010
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 . 18
6.2.3 Calibration of the equipment . 19
6.2.4 Measurement procedure . 20
6.2.5 Calculations and results . 21
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 . 25
6.3.5 Uncertainties . 25
6.4 Recirculating delay line method . 27
6.4.1 Short description and advantages . 27
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
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 DL(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 12 – Placing the beginning of section D outside the attenuation dead zone . 35
Figure A.1 – Recirculating delay line .
...