EN 60793-1-44:2011

SLOVENSKI STANDARD
01-september-2011
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SIST EN 60793-1-44:2004
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Optical fibres - Part 1-44: Measurement methods and test procedures - Cut-off
wavelength (IEC 60793-1-44:2011)
Lichtwellenleiter - Messmethoden und Prüfverfahren - Teil 1-44: Grenzwellenlänge (IEC
60793-1-44:2011)
Fibres optiques - Partie 1-44: Méthodes de mesure et procédures d'essai - Longueur
d'onde de coupure (CEI 60793-1-44:2011)
Ta slovenski standard je istoveten z: EN 60793-1-44:2011
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 60793-1-44
NORME EUROPÉENNE
June 2011
EUROPÄISCHE NORM
ICS 33.180.10 Supersedes EN 60793-1-44:2002

English version
Optical fibres -
Part 1-44: Measurement methods and test procedures -
Cut-off wavelength
(IEC 60793-1-44:2011)
Fibres optiques -  Lichtwellenleiter -
Partie 1-44: Méthodes de mesure et Messmethoden und Prüfverfahren -
procédures d'essai - Teil 1-44: Grenzwellenlänge
Longueur d'onde de coupure (IEC 60793-1-44:2011)
(CEI 60793-1-44:2011)
This European Standard was approved by CENELEC on 2011-05-25. 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, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60793-1-44:2011 E
Foreword
The text of document 86A/1369/FDIS, future edition 2 of IEC 60793-1-44, prepared by SC 86A, Fibres
and cables, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was
approved by CENELEC as EN 60793-1-44 on 2011-05-25.
This European Standard supersedes EN 60793-1-44:2002.
The main change with respect to EN 60793-1-44:2002 is the withdrawal of Annex D.
Annexes A, B and C form an integral part of EN 60793-1-44:2011.
This standard should be read in conjunction with EN 60793-1-1.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2012-02-25
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2014-05-25
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60793-1-44:2011 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 60793-2-50 NOTE  Harmonized as EN 60793-2-50.
IEC 60793-2-60 NOTE  Harmonized as EN 60793-2-60.
__________
- 3 - EN 60793-1-44:2011
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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  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 60793-1-1 - Optical fibres - EN 60793-1-1 -
Part 1-1: Measurement methods and test
procedures - General and guidance

IEC 60793-1-40 - Optical fibres - EN 60793-1-40 -
(mod) Part 1-40: Measurement methods and test
procedures - Attenuation
IEC 60793-1-44 ®
Edition 2.0 2011-04
INTERNATIONAL
STANDARD
Optical fibres –
Part 1-44: Measurement methods and test procedures – Cut-off wavelength

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 33.180.10 ISBN 978-2-88912-451-0
– 2 – 60793-1-44 ã IEC:2011(E)
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Background . 6
4 Overview of methods . 7
5 Mapping functions . 7
6 Reference test method . 8
7 Apparatus . 8
7.1 Light source . 8
7.2 Modulation . 8
7.3 Launch optics . 8
7.4 Support and positioning apparatus . 8
7.5 Cladding mode stripper . 8
7.6 Deployment mandrel . 9
7.6.1 General . 9
7.6.2 Cable cut-off wavelength, Method A . 9
7.6.3 Cable cut-off wavelength, Method B . 9
7.6.4 Fibre cut-off wavelength, Method C . 9
7.7 Detection optics . 11
7.8 Detector assembly and signal detection electronics . 11
8 Sampling and specimens . 11
8.1 Specimen length. 11
8.2 Specimen end face . 12
9 Procedure . 12
9.1 Positioning of specimen in apparatus . 12
9.1.1 General requirements for all methods . 12
9.1.2 Deployment requirements for each method . 12
9.2 Measurement of output power . 12
9.2.1 Overview . 12
9.2.2 Bend-reference technique . 13
9.2.3 Multimode-reference technique . 13
10 Calculations . 13
10.1 Bend-reference technique . 13
10.2 Multimode-reference technique . 14
10.3 Curve-fitting technique for improved precision (optional) . 14
10.3.1 General . 14
10.3.2 Step 1, define the upper-wavelength region . 15
10.3.3 Step 2, characterize the attenuation curve . 15
10.3.4 Step 3, determine the upper wavelength of the transition region . 16
10.3.5 Step 4, determine the lower wavelength of the transition region . 16
10.3.6 Step 5, characterize the transition region with the theoretical model . 16
10.3.7 Step 6, compute the cut-off wavelength, l . 17
c
11 Results . 17
11.1 Report the following information with each measurement: . 17
11.2 The following information shall be available upon request: . 17

60793-1-44 ã IEC:2011(E) – 3 –
12 Specification information . 18
Annex A (normative) Requirements specific to method A – Cable cut-off wavelength,
l , using uncabled fibre . 19
cc
Annex B (normative) Requirements specific to method B – Cable cut-off wavelength,
l , using cabled fibre . 20
cc
Annex C (normative) Requirements specific to method C – Fibre cut-off wavelength,
l . 21
c
Bibliography . 22

Figure 1 – Deployment configuration for cable cut-off wavelength, method A . 9
Figure 2 – Deployment configuration for cable cut-off wavelength, method B . 10
Figure 3 – Default configuration to measure l . 10
c
Figure 4 – Deployment configurations for fibre cut-off measurement . 11
Figure 5 – Cut-off wavelength using the bend-reference technique . 12
Figure 6 – Cut-off wavelength using the multimode-reference technique . 13

– 4 – 60793-1-44  IEC:2011(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRES –
Part 1-44: Measurement methods and test procedures –
Cut-off wavelength
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60793-1-44 has been prepared by subcommittee 86A: Fibres and
cables, of IEC technical committee 86: Fibre optics.
This second edition cancels and replaces the first edition published in 2001. This edition
constitutes a technical revision.
The main change with respect to the previous edition is the withdrawal of annex D.
Annexes A, B and C form an integral part of this standard.
This standard should be read in conjunction with IEC 60793-1-1.

60793-1-44 ã IEC:2011(E) – 5 –

The text of this standard is based on the following documents:
FDIS Report on voting
86A/1369/FDIS 86A/1385/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60793-1-4x series, published under the general title Optical fibres
– measurement methods and test procedures, can be found on the IEC website
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – 60793-1-44 ã IEC:2011(E)
OPTICAL FIBRES –
Part 1-44: Measurement methods and test procedures –
Cut-off wavelength
1 Scope
This part of IEC 60793 establishes uniform requirements for measuring the cut-off wavelength
of single-mode optical fibre, thereby assisting in the inspection of fibres and cables for
commercial purposes.
This standard gives the methods for measuring the cut-off wavelength of fibre and cable
There are two methods for measuring cable cut-off wavelength, l :
cc
· Method A: using uncabled fibre;
· Method B: using cabled fibre.
There is only one method (Method C) for measuring fibre cut-off wavelength, l .
c
The test method in this standard describes procedures for determining the cut-off wavelength
of a sample fibre in either an uncabled condition (l ) or in a cable (l ). Three default
c cc
configurations are given here: any different configuration will be given in a detail specification.
These procedures apply to all category B and C fibre types (see Normative references).
All methods require a reference measurement. There are two reference-scan techniques,
either or both of which may be used with all methods:
· bend-reference technique;
· multimode-reference technique using category A1 multimode fibre.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60793-1-1, Optical fibres – Part 1-1: Measurement methods and test procedures –
General and guidance
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation
3 Background
Theoretical cut-off wavelength is the shortest wavelength at which only the fundamental mode
can propagate in a single-mode fibre, as computed from the refractive index profile of the
fibre.
In optical fibres, the change from multimode to single-mode behaviour does not occur at an
isolated wavelength, but rather smoothly over a range of wavelengths. For purposes of

60793-1-44 ã IEC:2011(E) – 7 –
determining fibre performance in a telecommunications network, theoretical cut-off
wavelength is less useful than the lower value actually measured when the fibre is deployed.
Measured cut-off wavelength is defined as the wavelength greater than which the ratio
between the total power, including launched higher-order modes, and the fundamental mode
power has decreased to less than 0,1 dB. According to this definition, the second-order (LP )
mode undergoes 19,3 dB more attenuation than the fundamental (LP ) mode at the cut-off
wavelength.
Because measured cut-off wavelength depends on the length and bends of the fibre, the
resulting value of cut-off wavelength depends on whether the measured fibre is configured in
a deployed, cabled condition, or it is short and uncabled. Consequently, there are two overall
types of cut-off wavelength:
· Cable cut-off wavelength, measured in an uncabled fibre deployment condition
(method A), or in a cabled condition (method B);
· Fibre cut-off wavelength, measured on a short length of uncabled, primary-coated
fibre.
Cable cut-off wavelength is the preferred attribute to be specified and measured.
4 Overview of methods
All of the methods shall use the transmitted-power technique, which measures the variation
with wavelength of the transmitted power of a fibre under test compared to a reference
transmitted-power wavelength scan. The reference scan normalizes wavelength-dependent
fluctuations in the measurement equipment so that the attenuation of the LP mode in the
specimen can be properly characterized and the cut-off wavelength precisely determined.
The reference scan uses one of the following two techniques:
· the specimen with an additional, smaller-radius fibre bend;
· a (separate) category A1 multimode fibre.
This procedure can determine the cut-off wavelength of a fibre specimen in either a cabled or
uncabled condition. Each method has its own default configurations; the detail specification
will give any different configuration required.
The fibre cut-off wavelength, (l ), measured under the standard length and bend conditions
c
described in this standard, will generally exhibit a value larger than l . For normal installed
cc
cable spans, it is common for the measured l value to exceed the system transmission
c
wavelength. Thus cable cut-off wavelength is the more useful description of system
performance and capability.
For short cables, e.g. a pigtail with a length shorter (and possibly a bending radius larger)
than described in this method, the cable may introduce modal noise near the cut-off
wavelength when lossy splices are present (>0.5 dB).
5 Mapping functions
A mapping function is a formula by which the measured results of one type of cut-off
wavelength are used to predict the results that one would obtain from another type.
An empirical mapping function is specific to a particular fibre type and design. Generate
mapping functions by doing an experiment in which samples of fibre are chosen to represent
the spectrum of cut-off wavelength values for the fibre type, then measure the values using

– 8 – 60793-1-44 ã IEC:2011(E)
the two methods to be mapped. Linear regression of the respe
...