IEC 60793-1-40:2024

Optical fibres - Part 1-40: Attenuation measurement methods

IEC 60793-1-40:2024 establishes uniform requirements for measuring the attenuation of optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. Four methods are described for measuring attenuation, one being that for modelling spectral attenuation:
-method A: cut-back;
-method B: insertion loss;
-method C: backscattering;
-method D: modelling spectral attenuation.
Methods A to C apply to the measurement of attenuation for all categories of the following fibres:
-class A multimode fibres;
-class B single-mode fibres.
Method C, backscattering, also covers the location, losses and characterization of point discontinuities.
Method D is applicable only to class B fibres.
Information common to all four methods appears in Clause 1 to Clause 11, and information pertaining to each individual method appears in Annex A, Annex B, Annex C, and Annex D, respectively.
This third edition cancels and replaces the second edition published in 2019. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) modifying the definition of attenuation to be compatible with the definition in electropedia.org

Fibres optiques - Partie 1-40: Méthodes de mesure de l'affaiblissement

L'IEC 60793-1-40:2024 établit des exigences harmonisées pour mesurer l'affaiblissement d'une fibre optique, contribuant ainsi au contrôle des fibres et des câbles à des fins commerciales. Quatre méthodes sont décrites pour mesurer l'affaiblissement, parmi lesquelles une méthode pour modéliser l'affaiblissement spectral:
-méthode A: fibre coupée;
-méthode B: pertes d'insertion;
-méthode C: rétrodiffusion;
-méthode D: modélisation de l'affaiblissement spectral.
Les méthodes A à C s'appliquent au mesurage de l'affaiblissement pour toutes les catégories de fibres suivantes:
-fibres multimodales de classe A;
-fibres unimodales de classe B.
La méthode C, rétrodiffusion, s'applique aussi à la localisation, aux pertes et à la caractérisation des discontinuités ponctuelles.
La méthode D s'applique uniquement aux fibres de classe B.
Les informations communes à ces quatre méthodes sont présentées aux Articles 1 à 11, et les informations propres à chaque méthode individuelle, sont présentées à l'Annexe A, l'Annexe B, l'Annexe C et l'Annexe D, respectivement.
Cette troisième édition annule et remplace la deuxième édition parue en 2019. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) modification de la définition de l'affaiblissement pour s'aligner sur la définition du site electropedia.org

General Information

• Status: Published
• Publication Date: 26-Nov-2024
• ICS: 33.180.10 - Fibres and cables
• Technical Committee: SC 86A - Fibres and cables
• Drafting Committee: WG 1 - TC 86/SC 86A/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 20-Dec-2024
• Completion Date: 27-Nov-2024

Relations

• Revises: IEC 60793-1-40:2019 - Optical fibres - Part 1-40: Attenuation measurement methods
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60793-1-40 ®
Edition 3.0 2024-11
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Optical fibres –
Part 1-40: Attenuation measurement methods

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.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
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 corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews, graphical symbols and the glossary.
committee, …). It also gives information on projects, replaced With a subscription you will always have access to up to date
and withdrawn publications. content tailored to your needs.

IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and once
containing more than 22 500 terminological entries in English
a month by email.
and French, with equivalent terms in 25 additional languages.

Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
If you wish to give us your feedback on this publication or need

further assistance, please contact the Customer Service
Centre: [e-mail].
IEC 60793-1-40 ®
Edition 3.0 2024-11
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Optical fibres –
Part 1-40: Attenuation measurement methods
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.10 ISBN 978-2-8327-0067-9

– 2 – IEC 60793-1-40:2024 RLV © IEC 2024
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 9
4 Calibration requirements . 9
5 Reference test method . 9
6 Apparatus . 9
7 Sampling and specimens Sample preparation . 9
7.1 SpecimenSample length . 9
7.2 SpecimenSample end face . 9
8 Procedure . 9
9 Calculations . 9
9.1 Methods A and B . 9
9.2 Method C . 10
9.3 Method D . 10
10 Results . 10
10.1 Information available with each measurement . 10
10.2 Information available upon request . 10
10.3 Method-specific additional information . 10
11 Specification information . 10
Annex A (normative) Requirements specific to method A – Cut-back . 11
A.1 General . 11
A.2 Apparatus . 11
A.2.1 General apparatus for all fibres. 11
A.2.2 Launch apparatus for all single-mode fibres . 13
A.2.3 Launch apparatus for A1 multimode fibres . 14
A.2.4 Launch apparatus for A2 to A4 multimode fibres . 16
A.2.5 Calibration requirements . 17
A.3 Procedure . 18
A.4 Calculations . 18
Annex B (normative) Requirements specific to method B – Insertion loss . 19
B.1 General . 19
B.2 Apparatus . 19
B.2.1 General set-ups . 19
B.2.2 Apparatus common to method A (cut-back). 19
B.2.3 Additional apparatus specific to method B (insertion-loss) . 19
B.2.4 Calibration requirements . 19
B.3 Procedure . 19
B.4 Calculations . 20
Annex C (normative) Requirements specific to method C – Backscattering . 21
C.1 General . 21
C.2 Apparatus . 21
C.2.1 General . 21

C.2.2 Optical transmitter . 21
C.2.3 Launch conditions . 22
C.2.4 Optical splitter . 22
C.2.5 Optical receiver . 22
C.2.6 Pulse duration and repetition rate . 22
C.2.7 Signal processor . 22
C.2.8 Display . 22
C.2.9 Data interface (optional) . 23
C.2.10 Reflection controller (optional) . 23
C.2.11 Splices and connectors . 23
C.3 Sampling and specimens . 23
C.4 Procedure . 23
C.4.1 General measurement steps . 23
C.4.2 Further steps for measuring attenuation. 24
C.4.3 Further steps for measuring point discontinuities . 25
C.4.4 Calibration . 27
C.5 Calculations . 27
C.6 Results . 28
Annex D (normative) Requirements specific to method D – Spectral attenuation
modelling . 29
D.1 General . 29
D.2 Apparatus . 29
D.3 Sampling and specimens . 29
D.4 Procedure . 29
D.5 Calculations . 30
D.6 Results . 31
Annex E (informative) Examples of short cable test results on A1 multimode fibres . 32
Bibliography . 34

Figure A.1 – Arrangement of equipment for loss measurement at a specified
wavelength . 11
Figure A.2 – Arrangement of equipment used to obtain loss spectrum . 12
Figure A.3 – General launch arrangement . 12
Figure A.4 – Limited phase space launch optics . 15
Figure A.5 – Two examples of optical fibre scramblers . 16
Figure A.6 – Lens system . 16
Figure A.7 – Launch fibre . 17
Figure A.8 – Mode scrambler (for A.4 fibre) . 17
Figure A.9 – A wide-spectrum source (line "b") could lead to attenuation measurement
errors due to sharp variations on spectral attenuation of polymer-core fibres (line "a") . 18
Figure B.1 – Calibration of insertion loss measurement set . 20
Figure B.2 – Measurement of insertion loss . 20
Figure C.1 – Block diagram of an OTDR . 21
Figure C.2 – Schematic OTDR trace for a "uniform" specimen preceded by a dead-
zone fibre . 24
Figure C.3 – Schematic OTDR trace for a "uniform" specimen not preceded by a dead-
zone fibre . 24

– 4 – IEC 60793-1-40:2024 RLV © IEC 2024
Figure C.4 – Schematic OTDR trace showing apparent loss due to point
discontinuities, one reflective and one non-reflective . 26
Figure C.5 – Schematic of an expanded OTDR trace showing two point discontinuities,
one with apparent gain, and another with no apparent loss or gain . 27
Figure E.1 – Example of attenuation coefficient tests on A1a.1 A1-OM2 fibre . 32
Figure E.2 – Example of attenuation coefficient tests on A1a.3 A1-OM4 fibre . 32
Figure E.3 – Example of attenuation coefficient tes
...