EN IEC 60793-1-49:2018

Optical fibres - Part 1-49: Measurement methods and test procedures - Differential mode delay

IEC 60793-49:2018 applies only to multimode, graded-index glass-core (category A1) fibres. The test method is commonly used in production and research facilities, but is not easily accomplished in the field. This document describes a method for characterizing the modal structure of a graded-index multimode fibre. This information is useful for assessing the bandwidth performance of a fibre especially when the fibre is intended to support a range of launch conditions, for example, those produced by standardized laser transmitters. This third edition cancels and replaces the second edition published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) better alignment with original intent by filling some omissions and therefore improving measurement rigor; b) the measurement of fibres with smaller differential mode delay (and higher modal bandwidth) such as type A1a.3 fibres of IEC 60793-2-10 that are used in constructing OM4 performance category cables; new requirements on specifying detector amplitude and temporal response, specimen deployment conditions, four-quadrant scanning, and uniformity of radial locations for calculating bandwidth. Keywords: modal structure of a graded-index multimode fibre, bandwidth performance

Lichtwellenleiter - Teil 1-49: Messmethoden und Prüfverfahren - Gruppenlaufzeitdifferenz

Fibres optiques - Partie 1-49: Méthodes de mesure et procédures d'essai - Retard différentiel de mode

IEC 60793-1-49:2018 s'applique uniquement aux fibres multimodales à cœur en verre à gradient d'indice (catégorie A1). Cette méthode d'essai, qui est généralement utilisée dans les installations de production et de recherche, n'est pas facilement réalisée sur le terrain. Le présent document décrit une méthode de caractérisation de la structure modale d'une fibre multimodale à gradient d'indice. Cette information est utile pour évaluer les performances de largeur de bande d'une fibre, en particulier lorsque la fibre est destinée à supporter une plage de conditions d'injection, par exemple celles produites par les émetteurs lasers normalisés. Cette troisième édition annule et remplace la deuxième édition parue en 2006 dont elle constitue une révision technique. La présente édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) un meilleur alignement sur l'objectif initial en remédiant à certaines omissions pour améliorer la rigueur des mesures; b) la mesure des fibres avec un plus petit retard différentiel de mode (et une plus grande largeur de bande modale) telles que des fibres de type A1a.3 de l'IEC 60793-2-10 utilisées pour construire des câbles de catégorie de performance OM4, de nouvelles exigences sur la spécification de l'amplitude du détecteur et de la réponse temporelle, les conditions de déploiement des spécimens, le balayage des quatre quadrants et l'uniformité des emplacements radiaux pour calculer la largeur de bande. Mots clés: structure modale d'une fibre multimodale à gradient d'indice, performances de largeur de bande

Optična vlakna - 1-49. del: Merilne metode in postopki preskušanja - Diferenčna zakasnitev rodov (IEC 60793-1-49:2018)

Ta del standarda IEC 60793 se uporablja samo za večrodna gradientna steklena vlakna (kategorija A1). Preskusna metoda se običajno uporablja v proizvodnji in raziskovalnih ustanovah, na terenu pa ni lahko izvedljiva.
Ta dokument opisuje metodo za opredelitev rodovne strukture gradientnih večrodnih vlaken. Te informacije so uporabne pri ocenjevanju prenosne zmogljivosti vlaken, še posebej, ko so vlakna namenjena podpori različnim zagonskim pogojem, na primer tistim, ki jih proizvedejo standardizirani laserski oddajniki.
S to metodo izhod enorodnega vlakna na sondi pri preskusni valovni dolžini presega preskušano večrodno vlakno. Točka sonde se skenira na končnem delu preskušanega optičnega vlakna v določenih radialnih položajih, na teh položajih pa se pridobi niz odzivnih impulzov.
Iz zbranega nabora podatkov je mogoče izpeljati tri določljive parametre.
• Prvi parameter, diferenčna zakasnitev rodov (DMD), je razlika v času zakasnitve optičnega impulza med najhitrejšimi in najpočasnejšimi skupinami rodov pri preskušanem vlaknu. Specifikacije diferenčne zakasnitve rodov omejujejo zakasnitev rodov v določenem območju radialno izravnanih položajev vlaken v sondi. Specifikacije diferenčne zakasnitve rodov se določijo z modeliranjem in eksperimentiranjem, da ustrezajo minimalni učinkoviti pasovni širini rodov (EMB) za pričakovan obseg oddajnikov, uporabljenih v povezavi na določeni ravni zmogljivosti.
• Drugi določljiv parameter je izpeljan z združevanjem impulzov s pomočjo niza določenih radialnih bremen, da se določi približek niza impulzov pri tipičnih oddajnikih. S Fourierovimi transformacijami se izračuna učinkovita pasovna širina rodov (EMBc) za vsak niz bremena. Najnižja vrednost teh vrednosti EMBc (minEMBc) je določljiv parameter.
• Tretji določljiv parameter, izračunana pasovna širina prepolnega zagona (OMBc), se določi na način, podoben vrednosti EMBc, vendar z uporabo samo enega niza bremena pri nizu impulzov; ta niz bremena ustreza pogoju prenapolnjenosti, kjer so vse skupine rodov enako vzbujene.
Namen preskusa je kvantifikacija učinkov interakcij rodovne strukture vlaken in izvornih rodovnih značilnosti, razen spektralne interakcije vira z barvno razpršenostjo vlaken. Dodajanje učinkov barvne razpršenosti vlaken in spektralnih značilnosti vira bo zmanjšalo skupno pasovno širino prenosa, vendar je to v večini modelov prenosa ločen izračun. Pri tem preskusu se prispevek barvne razpršenosti nadzoruje z omejevanjem spektralne širine uporabnih preskusnih virov. Praktični preskusni viri bodo imeli neničelno spektralno širino in bodo tako nekoliko izkrivili vrednosti DMD, minEMBc in OMBc. Ti učinki barvne razpršenosti so obravnavani v dodatku A.
OPOMBA: Primerjava med standardom IEC 60793-1-49 in priporočili ITU: Priporočilo ITU-T G.650.1 [2] ne vsebuje nobenih informacij o tem, kako izmeriti DMD gradientnega večrodnega vlakna.

General Information

• Status: Published
• Publication Date: 01-Nov-2018
• Withdrawal Date: 18-Sep-2021
• ICS: 33.180.10 - Fibres and cables
• Technical Committee: CLC/TC 86A - Optical fibres and optical fibre cables
• Drafting Committee: IEC/SC 86A - IEC_SC_86A
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 02-Nov-2018
• Completion Date: 02-Nov-2018
• Ref Project: SIST EN IEC 60793-1-49:2019 - Optical fibres - Part 1-49: Measurement methods and test procedures - Differential mode delay (IEC 60793-1-49:2018)

Relations

• Replaces: EN 60793-1-49:2006 - Optical fibres - Part 1-49: Measurement methods and test procedures - Differential mode delay
• Effective Date: 06-Nov-2018

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2019
1DGRPHãþD
SIST EN 60793-1-49:2007
2SWLþQDYODNQDGHO0HULOQHPHWRGHLQSRVWRSNLSUHVNXãDQMD'LIHUHQþQD
]DNDVQLWHYURGRY,(&
Optical fibres - Part 1-49: Measurement methods and test procedures - Differential mode
delay (IEC 60793-1-49:2018)
Lichtwellenleiter - Teil 1-49: Messmethoden und Prüfverfahren - Gruppenlaufzeitdifferenz
(IEC 60793-1-49:2018)
Fibres optiques - Partie 1-49: Méthodes de mesure et procédures d'essai - Retard
différentiel de mode (IEC 60793-1-49:2018)
Ta slovenski standard je istoveten z: EN IEC 60793-1-49:2018
ICS:
33.180.10 2SWLþQDYODNQDLQNDEOL Fibres and cables
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60793-1-49

NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2018
ICS 33.180.10 Supersedes EN 60793-1-49:2006
English Version
Optical fibres - Part 1-49: Measurement methods and test
procedures - Differential mode delay
(IEC 60793-1-49:2018)
Fibres optiques - Partie 1-49: Méthodes de mesure et Lichtwellenleiter - Teil 1-49: Messmethoden und
procédures d'essai - Retard différentiel de mode Prüfverfahren - Gruppenlaufzeitdifferenz
(IEC 60793-1-49:2018) (IEC 60793-1-49:2018)
This European Standard was approved by CENELEC on 2018-09-19. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60793-1-49:2018 E

European foreword
The text of document 86A/1812/CDV, future edition 3 of IEC 60793-1-49, prepared by SC 86A "Fibres
and cables" of IEC/TC 86 "Fibre optics" was submitted to the IEC-CENELEC parallel vote and
approved by CENELEC as EN IEC 60793-1-49:2018.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2019-06-19
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2021-09-19
document have to be withdrawn
This document supersedes EN 60793-1-49:2006.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice
The text of the International Standard IEC 60793-1-49:2018 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60793-2-10 NOTE Harmonized as EN 60793-2-10
IEC 60793-1-42 NOTE Harmonized as EN 60793-1-42

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60793-1-1 2017 Optical fibres - Part 1-1: Measurement methods EN 60793-1-1 2017
and test procedures - General and guidance
IEC 60793-1-22 -  Optical fibres - Part 1-22: Measurement methods EN 60793-1-22 -
and test procedures - Length measurement
IEC 60793-1-41 -  Optical fibres - Part 1-41: Measurement methods - -
and test procedures - Bandwidth
IEC 60793-1-45 -  Optical fibres - Part 1-45: Measurement methods EN IEC 60793-1-45 -
and test procedures - Mode field diameter
IEC 60825-1 -  Safety of laser products - Part 1: Equipment EN 60825-1 -
classification and requirements
IEC 60825-2 -  Safety of laser products - Part 2: Safety of optical EN 60825-2 -
fibre communication systems (OFCS)
IEC 61280-1-4 -  Fibre optic communication subsystem test EN 61280-1-4 -
procedures - Part 1-4: General communication
subsystems - Light source encircled flux
measurement method
IEC 60793-1-49 ®
Edition 3.0 2018-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibres –
Part 1-49: Measurement methods and test procedures – Differential mode delay

Fibres optiques –
Partie 1-49: Méthodes de mesure et procédures d'essai – Retard différentiel de

mode
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10 ISBN 978-2-8322-5954-2

– 2 – IEC 60793-1-49:2018 © IEC 2018
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Apparatus . 8
4.1 Overview. 8
4.2 Optical source . 9
4.3 Probe fibre . 10
4.4 Scanning stage . 10
4.5 Probe to test sample coupling . 10
4.6 Cladding mode stripper . 10
4.7 Detection system . 10
4.8 Sampler and digitizer . 11
4.9 Computational equipment . 11
4.10 System performance . 11
4.10.1 General . 11
4.10.2 Pulse temporal stability . 12
4.10.3 System stability frequency limit (SSFL) . 12
5 Sampling and specimens . 13
5.1 Test sample . 13
5.2 Specimen end-faces . 13
5.3 Specimen length . 13
5.4 Specimen deployment . 13
5.5 Specimen positioning . 13
6 Procedure . 13
6.1 Fibre coupling and system setup . 13
6.2 Determination of centre . 14
6.3 Measurement of the test sample . 14
6.3.1 Selection of radii and quadrant . 14
6.3.2 Collection of scan data . 14
6.4 Determination of ∆T and ∆T . 14
PULSE REF
6.5 Reference test method . 14
7 Calculations and interpretation of results . 15
7.1 General . 15
7.2 Differential mode delay (DMD) . 15
7.2.1 General . 15
7.2.2 Deconvolution . 15
7.2.3 Pulse folding . 15
7.2.4 Determination of DMD . 16
7.3 Minimum calculated effective modal bandwidth . 17
7.3.1 General . 17
7.3.2 Time domain pulse computation . 17
7.3.3 Calculate the transfer function . 18
7.3.4 Compute the power spectrum . 18
7.3.5 Compute EMB and minEMB . 18
c c
7.4 Length normalization . 18

IEC 60793-1-49:2018 © IEC 2018 – 3 –
8 Documentation . 18
8.1 Information to be reported . 18
8.2 Information available upon request . 19
9 Specification information . 19
Annex A (normative) Source spectral width limitation . 20
A.1 Limiting the effect of chromatic dispersion (CD) on the value of DMD . 20
A.1.1 General . 20
A.1.2 Limit CD contribution to DMD to be measured . 20
A.1.3 Limit CD contribution to reference width . 20
A.1.4 Adjust ∆T to account for CD contribution . 21
REF
A.1.5 High-performance DMD fibres and spectral requirements . 21
A.2 Chromatic dispersion in multimode fibres . 22
Annex B (informative) Determination of fibre optical centre . 23
B.1 General . 23
B.2 Method . 23
Annex C (normative) Detection system modal measurement . 26
C.1 General .
...