EN 60793-2-50:2016

SLOVENSKI STANDARD
01-maj-2016
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SIST EN 60793-2-50:2013
SIST EN 60793-2-50:2013/AC:2015
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Optical fibres - Part 2-50: Product specifications - Sectional specification for class B
single-mode fibres (IEC 60793-2-50:2015)
Ta slovenski standard je istoveten z: EN 60793-2-50:2016
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 60793-2-50

NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2016
ICS 33.180.10 Supersedes EN 60793-2-50:2013
English Version
Optical fibres - Part 2-50: Product specifications - Sectional
specification for class B single-mode fibres
(IEC 60793-2-50:2015)
Fibres optiques - Partie 2-50: Spécifications de produits - Lichtwellenleiter - Teil 2-50: Produktspezifikationen -
Spécification intermédiaire pour les fibres unimodales de Rahmenspezifikation für Einmodenfasern der Kategorie B
classe B (IEC 60793-2-50:2015)
(IEC 60793-2-50:2015)
This European Standard was approved by CENELEC on 2015-12-24. 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, 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: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60793-2-50:2016 E
European foreword
The text of document 86A/1571/CDV, future edition 5 of IEC 60793-2-50, 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 60793-2-50:2016.
The following dates are fixed:
(dop) 2016-09-24
• latest date by which the document has to be implemented at
national level by publication of an identical national
standard or by endorsement
(dow) 2018-12-24
• latest date by which the national standards conflicting with
the document have to be withdrawn

This document supersedes EN 60793-2-50:2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 60793-2-50:2015 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated :
IEC 60794-2 NOTE Harmonized as EN 60794-2.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When 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 series Optical fibres - EN 60793-1 series
Part 1: Measurement methods and test
procedures
IEC 60793-1-1 -  Optical fibres - EN 60793-1-1 -
Part 1-1: Measurement methods and
test procedures - General and guidance
IEC 60793-1-20 -  Optical fibres - EN 60793-1-20 -
Part 1-20: Measurement methods and
test procedures - Fibre geometry
IEC 60793-1-21 -  Optical fibres - EN 60793-1-21 -
Part 1-21: Measurement methods and
test procedures - Coating geometry
IEC 60793-1-22 -  Optical fibres - EN 60793-1-22 -
Part 1-22: Measurement methods and
test procedures - Length measurement
IEC 60793-1-30 -  Optical fibres - EN 60793-1-30 -
Part 1-30: Measurement methods and
test procedures - Fibre proof test
IEC 60793-1-31 -  Optical fibres - EN 60793-1-31 -
Part 1-31: Measurement methods and
test procedures - Tensile strength
IEC 60793-1-32 -  Optical fibres - EN 60793-1-32 -
Part 1-32: Measurement methods and
test procedures - Coating strippability
IEC 60793-1-33 -  Optical fibres - EN 60793-1-33 -
Part 1-33: Measurement methods and
test procedures - Stress corrosion
susceptibility
IEC 60793-1-34 -  Optical fibres - EN 60793-1-34 -
Part 1-34: Measurement methods and
test procedures - Fibre curl
Publication Year Title EN/HD Year
IEC 60793-1-40 (mod) 2001 Optical fibres - EN 60793-1-40 2003
Part 1-40: Measurement methods and
test procedures - Attenuation
IEC 60793-1-42 -  Optical fibres - EN 60793-1-42 -
Part 1-42: Measurement methods and
test procedures - Chromatic dispersion
IEC 60793-1-44 -  Optical fibres - EN 60793-1-44 -
Part 1-44: Measurement methods and
test procedures - Cut-off wavelength
IEC 60793-1-45 -  Optical fibres - EN 60793-1-45 -
Part 1-45: Measurement methods and
test procedures - Mode field diameter
IEC 60793-1-46 -  Optical fibres - EN 60793-1-46 -
Part 1-46: Measurement methods and
test procedures - Monitoring of changes
in optical transmittance
IEC 60793-1-47 -  Optical fibres - EN 60793-1-47 -
Part 1-47: Measurement methods and
test procedures - Macrobending loss
IEC 60793-1-48 -  Optical fibres - EN 60793-1-48 -
Part 1-48: Measurement methods and
test procedures - Polarization mode
dispersion
IEC 60793-1-50 -  Optical fibres - EN 60793-1-50 -
Part 1-50: Measurement methods and
test procedures - Damp heat (steady
state) tests
IEC 60793-1-51 -  Optical fibres - EN 60793-1-51 -
Part 1-51: Measurement methods and
test procedures - Dry heat (steady state)
tests
IEC 60793-1-52 -  Optical fibres - EN 60793-1-52 -
Part 1-52: Measurement methods and
test procedures - Change of
temperature tests
IEC 60793-1-53 -  Optical fibres - EN 60793-1-53 -
Part 1-53: Measurement methods and
test procedures - Water immersion tests
IEC 60793-2 -  Optical fibres - EN 60793-2 -
Part 2: Product specifications - General
IEC 60794-3 -  Optical fibre cables - EN 60794-3 -
Part 3: Outdoor cables - Sectional
specification
IEC/TR 62316 -  Guidance for the interpretation of OTDR - -
backscattering traces
IEC 60793-2-50 ®
Edition 5.0 2015-11
INTERNATIONAL
STANDARD
colour
inside
Optical fibres –
Part 2-50: Product specifications – Sectional specification for class B

single-mode fibres
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.10 ISBN 978-2-8322-3023-7

– 2 – IEC 60793-2-50:2015 © IEC 2015
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Abbreviations and symbols . 9
5 Specifications . 9
5.1 General . 9
5.2 Dimensional requirements . 9
5.3 Mechanical requirements . 10
5.4 Transmission requirements . 11
5.5 Environmental requirements . 12
5.5.1 General . 12
5.5.2 Optical environmental requirements – Attenuation . 13
5.5.3 Mechanical environmental requirements . 13
Annex A (normative) Family specification for category B1.1 single-mode fibres . 15
A.1 General . 15
A.2 Dimensional requirements . 15
A.3 Mechanical requirements . 15
A.4 Transmission requirements . 16
A.5 Environmental requirements . 16
Annex B (normative) Family specification for category B1.2 single-mode fibres . 17
B.1 General . 17
B.2 Dimensional requirements . 17
B.3 Mechanical requirements . 17
B.4 Transmission requirements . 18
B.5 Environmental requirements . 18
Annex C (normative) Family specification for category B1.3 single-mode fibres . 19
C.1 General . 19
C.2 Dimensional requirements . 19
C.3 Mechanical requirements . 19
C.4 Transmission requirements . 20
C.5 Hydrogen ageing for category B1.3 . 20
C.6 Environmental requirements . 21
Annex D (normative) Family specification for category B2 single-mode fibres . 22
D.1 General . 22
D.2 Dimensional requirements . 22
D.3 Mechanical requirements . 22
D.4 Transmission requirements . 23
D.4.1 General . 23
D.4.2 Chromatic dispersion coefficient requirement for sub-category B2_a
fibres . 23
D.4.3 Chromatic dispersion coefficient requirement for sub-category B2_b
fibres . 24
D.5 Environmental requirements . 24
Annex E (normative) Family specification for category B4 single-mode fibres . 25
E.1 General . 25

IEC 60793-2-50:2015 © IEC 2015 – 3 –
E.2 Dimensional requirements . 25
E.3 Mechanical requirements . 25
E.4 Transmission requirements . 26
E.4.1 General . 26
E.4.2 Chromatic dispersion coefficient limits for sub-category B4_c fibres . 26
E.4.3 Chromatic dispersion coefficient limits for sub-category B4_d fibres . 27
E.4.4 Chromatic dispersion coefficient limits for sub-category B4_e fibres . 27
E.5 Environmental requirements . 27
Annex F (normative) Family specification for category B5 single-mode fibres . 28
F.1 General . 28
F.2 Dimensional requirements . 28
F.3 Mechanical requirements . 28
F.4 Transmission requirements . 29
F.4.1 General . 29
F.4.2 Chromatic dispersion coefficient for category B5 fibres . 29
F.5 Environmental requirements . 30
Annex G (normative) Family specification for category B6 single-mode fibres . 31
G.1 General . 31
G.2 Dimensional requirements . 31
G.3 Mechanical requirements . 32
G.4 Transmission requirements . 32
G.5 Environmental requirements . 33
Annex H (informative) System design information for category B4 single-mode fibres . 34
H.1 General . 34
H.2 One standard deviation limits for sub-category B4_d fibres . 34
H.3 One standard deviation limits for sub-category B4_e fibres . 35
Annex I (informative) Map from IEC nomenclature to ITU-T recommendations . 36
Bibliography . 37

Figure H.1 – Sub-category B4_d chromatic dispersion coefficient limits . 35
Figure H.2 – Sub-category B4_e chromatic dispersion coefficient limits . 35

Table 1 – Dimensional attributes and measurement methods . 9
Table 2 – Dimensional requirements common to all category B fibres . 10
Table 3 – Mechanical attributes and test methods . 10
Table 4 – Mechanical requirements common to all class B fibres . 11
Table 5 – Transmission attributes and measurement methods . 11
Table 6 – Transmission, requirements common to all class B fibres . 12
Table 7 – Additional transmission attributes required in the family specifications . 12
Table 8 – Environmental exposure tests . 12
Table 9 – Attributes measured in environmental exposure tests . 12
Table 10 – Change in attenuation for environmental tests . 13
Table 11 – Coating strip force for environmental tests . 13
Table 12 – Tensile strength for environmental tests . 13
Table 13 – Stress corrosion susceptibility for environmental tests . 14
Table A.1 – Dimensional requirements specific to category B1.1 fibres . 15

– 4 – IEC 60793-2-50:2015 © IEC 2015
Table A.2 – Mechanical requirements specific to category B1.1 fibres . 15
Table A.3 – Transmission requirements specific to category B1.1 fibres . 16
Table B.1 – Dimensional requirements specific to category B1.2 fibres . 17
Table B.2 – Mechanical requirements specific to category B1.2 fibres . 18
Table B.3 – Transmission requirements specific to category B1.2 fibres . 18
Table C.1 – Dimensional requirements specific to category B1.3 fibres . 19
Table C.2 – Mechanical requirements specific to category B1.3 fibres . 19
Table C.3 – Transmission requirements specific to category B1.3 fibres . 20
Table D.1 – Dimensional requirements specific to category B2 fibres . 22
Table D.2 – Mechanical requirements specific to category B2 fibres . 23
Table D.3 – Transmission requirements specific to category B2 fibres . 23
Table E.1 – Dimensional requirements specific to category B4 fibres . 25
Table E.2 – Mechanical requirements specific to category B4 fibres . 26
Table E.3 – Transmission requirements specific to category B4 fibres . 26
Table F.1 – Dimensional requirements specific to category B5 fibres . 28
Table F.2 – Mechanical requirements specific to category B5 fibres . 29
Table F.3 – Transmission requirements specific to category B5 fibres . 29
Table G.1 – Dimensional requirements specific to category B6 fibres . 32
Table G.2 – Mechanical requirements specific to category B6 fibres . 32
Table G.3 – Transmission requirements specific to category B6 fibres . 33
Table H.1 – Examples for λ = 1 530 nm and λ = 1 565 nm . 34
min max
Table I.1 – Map of IEC to ITU . 36

IEC 60793-2-50:2015 © IEC 2015 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRES –
Part 2-50: Product specifications –
Sectional specification for class B single-mode fibres

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 60793-2-50 has been prepared by subcommittee 86A: Fibres and
cables, of IEC technical committee 86: Fibre optics.
This fifth edition cancels and replaces the fourth edition, published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) aligns the requirements with the ITU-T Recommendations G.654 (2012-10) and G.657
(2012-10);
b) adds a new sub-category B1.2_d;
c) modifies B6 sub-categories in terms of attenuation and chromatic dispersion coefficient.

– 6 – IEC 60793-2-50:2015 © IEC 2015
The text of this standard is based on the following documents:
CDV Report on voting
86A/1571/CDV 86A/1614/RVC
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 in the IEC 60793 series published under the general title Optical fibres, 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
IEC 60793-2-50:2015 © IEC 2015 – 7 –
OPTICAL FIBRES –
Part 2-50: Product specifications –
Sectional specification for class B single-mode fibres

1 Scope
This part of IEC 60793 is applicable to optical fibre categories B1.1, B1.2, B1.3, B2, B4, B5
and B6. A map illustrating the connection of IEC designations to ITU-T designations is shown
in Annex I. These fibres are used or can be incorporated in information transmission
equipment and optical fibre cables.
Three types of requirements apply to these fibres:
– general requirements, as defined in IEC 60793-2;
– specific requirements common to the class B single-mode fibres covered in this standard
and which are given in Clause 5;
– particular requirements applicable to individual fibre categories or specific applications,
which are defined in Annexes A to G.
For some fibre categories (shown in the relevant family specifications), there are sub-
categories that are distinguished on the basis of difference in transmission attribute
specifications. The designations for these sub-categories are documented in the individual
family specifications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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 (all parts), Optical fibres – Measurement methods and test procedures
IEC 60793-1-1, Optical fibres – Measurement methods and test procedures – Part 1-1:
General and guidance
IEC 60793-1-20, Optical fibres – Part 1-20: Measurement methods and test procedures –
Fibre geometry
IEC 60793-1-21, Optical fibres – Part 1-21: Measurement methods and test procedures –
Coating geometry
IEC 60793-1-22, Optical fibres – Part 1-22: Measurement methods and test procedures –
Length measurement
IEC 60793-1-30, Optical fibres – Part 1-30: Measurement methods and test procedures –
Fibre proof test
IEC 60793-1-31, Optical fibres – Part 1-31: Measurement methods and test procedures –
Tensile strength
– 8 – IEC 60793-2-50:2015 © IEC 2015
IEC 60793-1-32, Optical fibres – Part 1-32: Measurement methods and test procedures –
Coating strippability
IEC 60793-1-33, Optical fibres – Part 1-33: Measurement methods and test procedures –
Stress corrosion susceptibility
IEC 60793-1-34, Optical fibres – Part 1-34: Measurement methods and test procedures –
Fibre curl
IEC 60793-1-40:2001, Optical fibres – Part 1-40: Measurement methods and test procedures
– Attenuation
IEC 60793-1-42, Optical fibres – Part 1-42: Measurement methods and test procedures –
Chromatic dispersion
IEC 60793-1-44, Optical fibres – Part 1-44: Measurement methods and test procedures – Cut-
off wavelength
IEC 60793-1-45, Optical fibres – Part 1-45: Measurement methods and test procedures –
Mode field diameter
IEC 60793-1-46, Optical fibres – Part 1-46: Measurement methods and test procedures –

Monitoring of changes in optical transmittance
IEC 60793-1-47, Optical fibres – Part 1-47: Measurement methods and test procedures –
Macrobending loss
IEC 60793-1-48, Optical fibres – Part 1-48: Measurement methods and test procedures –
Polarization mode dispersion
IEC 60793-1-50, Optical fibres – Part 1-50: Measurement methods and test procedures –
Damp heat (steady state) tests
IEC 60793-1-51, Optical fibres – Part 1-51: Measurement methods and test procedures – Dry
heat (steady state) tests
IEC 60793-1-52, Optical fibres – Part 1-52: Measurement methods and test procedures –
Change of temperature tests
IEC 60793-1-53, Optical fibres – Part 1-53: Measurement methods and test procedures –
Water immersion tests
IEC 60793-2, Optical fibres − Part 2: Product specifications – General
IEC 60794-3, Optical fibre cables – Part 3: Outdoor cables – Sectional specification
IEC TR 62316, Guidance for the interpretation of OTDR backscattering traces
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60793-2 and the
IEC 60793-1 series apply.
NOTE General definitions for fibres are provided in IEC 60793-2. The definitions of the specified attributes are
contained in the relevant test methods standard of the IEC 60793-1 series, while general definitions for testing are
provided in IEC 60793-1-1.
IEC 60793-2-50:2015 © IEC 2015 – 9 –
4 Abbreviations and symbols
For the purposes of this document, the following abbreviations and symbols apply:
λ zero dispersion wavelength
F average strip force
avg
F peak strip force
peak
MFD mode field diameter
n stress corrosion parameter – dynamic
d
PMD polarization mode dispersion
PMD PMD link design value
Q
5 Specifications
5.1 General
The fibre shall consist of a glass core and glass cladding in accordance with the construction
of optical fibre class B – single-mode fibre – as given in IEC 60793-2.
The term “glass” usually refers to material consisting of non-metallic oxides. The composition
of some fibres may be all glass, or glass and glass/hard polymeric composites.
5.2 Dimensional requirements
Relevant dimensional attributes and measurement methods are given in Table 1.
Requirements common to all categories of class B single-mode fibres are given in Table 2.
Cladding diameter, cladding non-circularity, and core concentricity error shall be specified in
the family specifications
Table 1 – Dimensional attributes and measurement methods
Attribute Measurement method
Cladding diameter IEC 60793-1-20
Cladding non-circularity IEC 60793-1-20
Core-cladding concentricity error IEC 60793-1-20
Primary coating diameter IEC 60793-1-21
Primary coating non-circularity IEC 60793-1-21
Primary coating-cladding concentricity error IEC 60793-1-21
Fibre length IEC 60793-1-22
– 10 – IEC 60793-2-50:2015 © IEC 2015
Table 2 – Dimensional requirements common to all category B fibres
Attribute Unit Limit
a
Primary coating diameter – uncoloured µm 235 to 255
a
Primary coating diameter – coloured 235 to 265
µm
Primary coating-cladding concentricity error
µm ≤ 12,5
b
Fibre length km
a
The above limits on primary coating diameter are most commonly used in telecommunications cables. There
are other applications, such as fibre for use within optical sub-systems, pigtails, or specialty applications
such as for submarines cables or for compact FTTH cables, which use other primary coating diameters,
several of which are listed below.
Alternative nominal primary coating diameters and ranges:
200 µm ± 10 µm (uncoloured; 190 µm to 220 µm coloured)
400 µm ± 40 µm
500 µm ± 30 µm
700 µm ± 100 µm
900 µm ± 100 µm
The primary coating cladding concentricity error should be limited to a maximum 10 µm for 200 µm.
Alternative coating diameters may impact fibre connectivity such as ribbons, multi-fibre connectors,
mechanical splices, and fusion splice protectors; they may also need adjustments to connectivity tools.
b
Length requirements vary and should be agreed between supplier and customer.

5.3 Mechanical requirements
Relevant mechanical attributes and test methods are given in Table 3. The relationship
between some of these attributes and mechanical reliability are described in IEC TR 62048.
Requirements common to all categories of class B single-mode fibres are given in Table 4.
Table 3 – Mechanical attributes and test methods
Attribute Test method
Proof test IEC 60793-1-30
Tensile strength IEC 60793-1-31
Coating strippability IEC 60793-1-32
Stress corrosion susceptibility IEC 60793-1-33
Fibre curl IEC 60793-1-34
IEC 60793-2-50:2015 © IEC 2015 – 11 –
Table 4 – Mechanical requirements common to all class B fibres
Attribute Unit Limit
a
Proof stress level GPa ≥ 0,69
b, c
Coating strip force (average) N 1,0 ≤ F ≤ 5,0

ave
b, c
Coating strip force (peak) N
1,0 ≤ F ≤ 8,9
peak
d
Fibre curl radius m
≥ 2
Tensile strength (median) for 0,5 m specimen length GPa ≥ 3,8
Stress corrosion susceptibility parameter, n –
≥ 18
d
a
The proof test value of 0,69 GPa equals about 1 % strain or about 8,8 N force. For the relation between
these different units, see IEC TR 62048:2014, 7.4.
b
Either average strip force or peak strip force, which are defined in the test procedure, may be specified with
agreement between supplier and customer.
c
In case of alternative nominal primary coating diameters (see Table 2), associated alternative coating strip
force values need to be agreed between supplier and customer.
d
Depending on splicing methods, a minimum of 4 m may be specified for fibre intended to be used in some
cable constructions – such as ribbon cable.

5.4 Transmission requirements
Relevant transmission attributes and measurement methods are given in Table 5.
Requirements common to all categories of class B single-mode fibres are shown in Table 6.
Requirements that shall be specified in the family specifications are listed in Table 7.
Table 5 – Transmission attributes and measurement methods
Attribute Measurement method
a
Attenuation coefficient IEC 60793-1-40
Chromatic dispersion IEC 60793-1-42
b
Cut-off wavelength IEC 60793-1-44
Mode field diameter IEC 60793-1-45
Change of optical transmission IEC 60793-1-46
Macrobending loss IEC 60793-1-47
Polarization mode dispersion IEC 60793-1-48
NOTE The indicated maximum attenuation values apply to uncabled optical fibres; for the maximum cabled
attenuation values, reference is made to IEC 60794-2, which can be used in conjunction with this standard.
a
The attenuation coefficient at various wavelengths can be calculated using the measured values at a few
wavelengths using a spectral model such as that given in IEC 60793-1-40. For example, the attenuation at
1 480 nm can be calculated and used for design of systems that employ remote pumping of optical
amplifiers. When using Method C, OTDR, additional guidance information in IEC TR 62316 shall be taken
into account. As reported in IEC 60793-1-40, the spectral attenuation model, to date, has only been
demonstrated on B1 and B2 fibres
b
There are two ways to measure cut-off wavelength, leading to: fibre cut-off wavelength λ and to cable cut-
c
off wavelength λ , respectively. The correlation of the measured values of λ and λ depends on the
cc c cc
specific fibre and cable design and the test conditions. While in general λ < λ a general quantitative
cc c
relationship cannot be easily established, the importance of ensuring single-mode transmission in the
minimum cable length between joints at the minimum operating wavelength is paramount. This may be
performed by recommending the maximum cable cut-off wavelength λ of a cabled single-mode fibre to be
cc
1 260 nm or for worst case length and bends by recommending a maximum fibre cut-off wavelength λ to
c
be 1 250 nm.
– 12 – IEC 60793-2-50:2015 © IEC 2015
Table 6 – Transmission, requirements common to all class B fibres
Attribute Unit Limit
a
Polarization mode dispersion (PMD) coefficient link ps/√km
design value (PMD )
Q
a
A maximum value of PMD on uncabled fibre shall be agreed between supplier and customer to satisfy the
Q
primary requirement of cable PMD, given in IEC 60794-3.

Table 7 – Additional transmission attributes required in the family specifications
Attribute
Attenuation coefficient and wavelengths
Chromatic dispersion characteristics
Nominal mode field diameter (MFD) range and wavelength
Mode field diameter tolerance
Cable cut-off wavelength
Macrobending loss including: wavelength, mandrel size, and number of turns
Cladding diameter
Cladding non-circularity
Core concentricity error
For category B4 fibre, information for system design is given in Annex H.
5.5 Environmental requirements
5.5.1 General
Environmental exposure tests and measurement methods are documented in two forms:
– relevant environmental attributes and test methods are given in Table 8;
– measurements of a particular mechanical or transmission attributes that may change on
the application of the environment are listed in Table 9.
Table 8 – Environmental exposure tests
Attribute Test method
Damp heat tests IEC 60793-1-50
Dry heat tests IEC 60793-1-51
Change of temperature tests IEC 60793-1-52
Water immersion tests IEC 60793-1-53

Table 9 – Attributes measured in environmental exposure tests
Attribute Test method
Change in optical transmission IEC 60793-1-46
Attenuation IEC 60793-1-40
Coating strip force IEC 60793-1-32
Tensile strength IEC 60793-1-31
Stress corrosion susceptibility IEC 60793-1-33

These tests are normally conducted periodically as type-tests for a fibre and coating design.
Unless otherwise indicated, the recovery period allowed between the completion of the

IEC 60793-2-50:2015 © IEC 2015 – 13 –
environmental exposure and performing the attribute measurements shall be as stated in the
particular environmental test method.
5.5.2 Optical environmental requirements – Attenuation
Change in attenuation from the initial value shall be less than the values in Table 10.
Attenuation shall be measured periodically during the entire exposure to each environment
and after removal.
Table 10 – Change in attenuation for environmental tests
Environment Wavelength Maximum attenuation increase
nm dB/km
Damp heat 1 550, 1 625 ≤ 0,05
Dry heat 1 550, 1 625
≤ 0,05
Change of temperature 1 550, 1 625
≤ 0,05
Water immersion 1 550, 1 625 ≤ 0,05
NOTE Attenuation changes at wavelengths lower than the test wavelength are smaller than the attenuation
change at the test wavelength.

5.5.3 Mechanical environmental requirements
5.5.3.1 General
These tests are, in practice, the most severe requirements amongst the environments defined
in Table 8.
5.5.3.2 Coating strip force
The attributes given in Table 11 shall be verified following removal of the fibre from the
particular environment.
Table 11 – Coating strip force for environmental tests
Environment Average strip force Peak strip force
N N
Damp heat 1,0 ≤ F ≤ 5,0 1,0 ≤ F ≤ 8,9
avg peak
Water immersion
1,0 ≤ F ≤ 5,0 1,0 ≤ F ≤ 8,9
avg peak
In case of alternative nominal primary coating diameters (see Table 2), associated alternative coating strip force
values need to be agreed between supplier and customer.

5.5.3.3 Tensile strength
The attributes given in Table 12 shall be verified following removal of the fibre from the
environment indicated.
Table 12 – Tensile strength for environmental tests
Median tensile strength (GPa), 15 percentile of the tensile strength
Environment
specimen length: 0,5 m distribution (GPa), specimen length: 0,5 m
Damp heat
≥ 3,03 ≥ 2,76
NOTE These requirements do not apply to hermetically coated fibre. (A hermetic coating is a protective layer
that completely segregates the glass fibre from moisture, thereby ensuring a high level of stress corrosion
resistance. Typical hermetic coating is a carbon layer of several microns thickness applied on the glass
surface.)
– 14 – IEC 60793-2-50:2015 © IEC 2015
5.5.3.4 Stress corrosion susceptibility
The attribute given in Table 13 shall be verified following removal of the fibre from the
environment indicated.
Table 13 – Stress corrosion susceptibility for environmental tests
Environment Stress corrosion susceptibility parameter, n
d
Damp heat
≥ 18
NOTE This requirement does not apply to hermetically coated fibre (see definition for hermetic coating in
Table 12).
IEC 60793-2-50:2015 © IEC 2015 – 15 –
Annex A
(normative)
Family specification for category B1.1 single-mode fibres
A.1 General
This dispersion unshifted single-mode fibre is optimized for use in the 1 310 nm region but
can be used in the 1 550 nm and 1 625 nm regions. Depending on link length and bit rates,
dispersion may need accommodation in the 1 550 nm and 1 625 nm regions.
The clauses and tables in Annex A contain particular requirements applicable to category
B1.1 fibres. Common requirements, repeated here for ease of reference from the sectional
specification, are noted by an entry in the “Reference” column. Relevant notes from the
SS
“ ”
sectional specification are not repeated but indicated with a superscript .
A.2 Dimensional requirements
Table A.1 contains dimensional requirements specific to category B1.1 fibres.
Table A.1 – Dimensional requirements specific to category B1.1 fibres
Attribute Unit Limit Reference
Cladding diameter 5.2
µm 125 ± 1
Cladding non-circularity % 5.2
≤ 1,0
Core concentricity error µm ≤ 0,6 5.2
a
Primary coating diameter – uncoloured 235 to 255 5.2
µm
a
Primary coating diameter – coloured 235 to 265 5.2
µm
Primary coating-cl
...