SIST EN IEC 60793-1-45:2018

SLOVENSKI STANDARD
01-april-2018
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Optical fibres - Part 1-45: Measurement methods and test procedures - Mode field
diameter (IEC 60793-1-45:2017)
Ta slovenski standard je istoveten z: EN IEC 60793-1-45:2018
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 60793-1-45

NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2018
ICS 33.180.10 Supersedes EN 60793-1-45:2003
English Version
Optical fibres - Part 1-45: Measurement methods and test
procedures - Mode field diameter
(IEC 60793-1-45:2017)
Fibre optiques - Partie 1-45: Méthodes de mesure et Lichtwellenleiter - Teil 1-45: Messmethoden - Messung des
procédures d'essai - Diamètre du champ de mode Modenfelddurchmessers
(IEC 60793-1-45:2017) (IEC 60793-1-45:2017)
This European Standard was approved by CENELEC on 2017-12-14. 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 60793-1-45:2018 E

European foreword
The text of document 86A/1758/CDV, future edition 2 of IEC 60793-1-45, prepared by IEC/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 60793-1-45:2018.

The following dates are fixed:
• latest date by which the document has to be (dop) 2018-09-14
implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2020-12-14
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60793-1-45:2003.

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 60793-1-45:2017 was approved by CENELEC as a
European Standard without any modification.
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 60793-1-40 2001 Optical fibres -- Part 1-40: Measurement EN 60793-1-40 2003
(mod) methods and test procedures - Attenuation
IEC 60793-2 -  Optical fibres -- Part 2: Product - -
specifications.
IEC 60793-1-45 ®
Edition 2.0 2017-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibres –
Part 1-45: Measurement methods and test procedures – Mode field diameter

Fibres optiques –
Partie 1-45: Méthodes de mesure et procédures d'essai – Diamètre du champ de

mode
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10 ISBN 978-2-8322-4979-6

– 2 – IEC 60793-1-45:2017 © IEC 2017
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 General consideration about mode field diameter . 7
5 Reference test method . 8
6 Apparatus . 8
6.1 General . 8
6.2 Light source . 8
6.3 Input optics . 9
6.4 Input positioner . 9
6.5 Cladding mode stripper . 9
6.6 High-order mode filter . 9
6.7 Output positioner . 9
6.8 Output optics . 9
6.9 Detector . 9
6.10 Computer . 9
7 Sampling and specimens . 10
7.1 Specimen length . 10
7.2 Specimen end face . 10
8 Procedure . 10
9 Calculations . 10
9.1 Basic equations . 10
9.2 Method A – Direct far-field scan . 10
9.3 Method B – Variable aperture in the far field . 11
9.4 Method C – Near-field scan . 11
10 Results . 12
10.1 Information available with each measurement . 12
10.2 Information available upon request . 12
11 Specification information . 12
Annex A (normative) Requirements specific to method A – Mode field diameter by
direct far-field scan . 14
A.1 Apparatus . 14
A.1.1 General . 14
A.1.2 Scanning detector assembly – Signal detection electronics . 14
A.1.3 Computer. 14
A.2 Procedure . 15
A.3 Calculations . 15
A.3.1 Determine folded power curve . 15
A.3.2 Compute the top (T) and bottom (B) integrals of Equation (1) . 15
A.3.3 Complete the calculation . 15
A.4 Sample data . 16
Annex B (normative) Requirements specific to method B – Mode field diameter by
variable aperture in the far field . 17
B.1 Apparatus . 17

IEC 60793-1-45:2017 © IEC 2017 – 3 –
B.1.1 General . 17
B.1.2 Output variable aperture assembly . 17
B.1.3 Output optics system . 18
B.1.4 Detector assembly and signal detection electronics . 18
B.2 Procedure . 18
B.3 Calculations . 18
B.3.1 Determine complementary aperture function . 18
B.3.2 Complete the integration . 19
B.3.3 Complete the calculation . 19
B.4 Sample data . 19
Annex C (normative) Requirements specific to method C – Mode field diameter by
near-field scan . 20
C.1 Apparatus . 20
C.1.1 General . 20
C.1.2 Magnifying output optics . 20
C.1.3 Scanning detector . 20
C.1.4 Detection electronics . 21
C.2 Procedure . 21
C.3 Calculations . 21
C.3.1 Calculate the centroid . 21
C.3.2 Fold the intensity profile . 22
C.3.3 Compute the integrals . 22
C.3.4 Complete the calculation . 22
C.4 Sample data . 23
Annex D (normative) Requirements specific to method D – Mode field diameter by
optical time domain reflectometer (OTDR) . 24
D.1 General . 24
D.2 Apparatus . 24
D.2.1 OTDR . 24
D.2.2 Optional auxiliary switches . 24
D.2.3 Optional computer . 25
D.2.4 Test sample . 25
D.2.5 Reference sample . 25
D.3 Procedure . 25
D.3.1 Orientation and notation . 25
D.4 Calculations . 26
D.4.1 Reference fibre mode field diameter . 26
D.4.2 Computation of the specimen mode field diameter . 27
D.4.3 Validation . 27
Annex E (informative) Sample data sets and calculated values . 29
E.1 General . 29
E.2 Method A – Mode field diameter by direct far-field scan . 29
E.3 Method B – Mode field diameter by variable aperture in the far field . 30
E.4 Method C – Mode field diameter by near-field scan . 30

Figure 1 – Transform relationships between measurement results . 8
Figure A.1 – Far-field measurement set . 14
Figure B.1 – Variable aperture by far-field measurement set . 17

– 4 – IEC 60793-1-45:2017 © IEC 2017
Figure C.1 – Near-field measurement set-ups . 20
Figure D.1 – Optical switch arrangement . 25
Figure D.2 – View from reference fibre A . 26
Figure D.3 – View from reference fibre B . 26
Figure D.4 – Validation example – Comparison of methods . 27

Table E.1 – Sample data, method A – Mode field diameter by direct far-field scan . 29
Table E.2 – Sample data set, method B – Mode field diameter by variable aperture in
the far field . 30
Table E.3 – Sample data set, method C – Mode field diameter by near-field scan . 30

IEC 60793-1-45:2017 © IEC 2017 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRES –
Part 1-45: Measurement methods and test procedures –
Mode field diameter
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 60793-1-45 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.
This edition includes the following significant technical changes with respect to the previous
edition:
a) improvement of the description of measurement details for B6 fibre;
b) correction of Equations (1), (2),(5) and (6);
c) correction of Table E.1, Table E.2 and Table E.3.

– 6 – IEC 60793-1-45:2017 © IEC 2017
The text of this International Standard is based on the following documents:
CDV Report on voting
86A/1758/CDV 86A/1802/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document 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 document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IEC 60793-1-45:2017 © IEC 2017 – 7 –
OPTICAL FIBRES –
Part 1-45: Measurement methods and test procedures –
Mode field diameter
1 Scope
This part of IEC 60793 establishes uniform requirements for measuring the mode field
diameter (MFD) of single-mode optical fibre, thereby assisting in the inspection of fibres and
cables for commercial purposes.
2 Normative references
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.
IEC 60793-1-40:2001, Optical fibres – Part 1-40: Measurement methods and test procedures
– Attenuation
IEC 60793-2, Optical fibres – Part 2: Product specifications – General
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 General consideration about mode field diameter
The mode field diameter measurement represents a measure of the transverse extent of the
electromagnetic field intensity of the guided mode in a fibre cross section, and it is defined
from the far-field intensity distribution as a ratio of integrals known as the Petermann II
definition. See Equation (1).
The definitions of mode field diameter are strictly related to the measurement configurations.
The mathematical equivalence of these definitions results from transform relationships
between measurement results obtained by different implementations summarized in Figure 1
as follows.
– 8 – IEC 60793-1-45:2017 © IEC 2017
Far-field
scan
Hankel
Integration
transform
Variable
Near-field
aperture
scan
technique
IEC
Figure 1 – Transform relationships between measurement results
Four methods are described for measuring mode field diameter:
– method A: direct far-field scan;
– method B: variable aperture in the far field;
– method C: near-field scan;
– method D: bi-directional backscatter using an optical time domain reflectometer (OTDR).
All four methods apply to all categories of type B single-mode fibre shown in IEC 60793-2 and
operating near 1 310 nm or 1 550 nm. Method D is not recommended for the measurement of
fibres of unknown type or design.
Information common to all four methods is contained in Clauses 1 to 11, and information
pertaining to each individual method appears in annexes A, B, C and D, respectively.
5 Reference test method
Method A, direct far-field scan, is the reference test method (RTM), which shall be the one
used to settle disputes.
6 Apparatus
6.1 General
The following apparatus is common to all measurement methods. Annexes A, B, C and D
include layout drawings and other equipment requirements for each of the four methods,
respectively.
6.2 Light source
For methods A, B and C, use a suitable coherent or non-coherent light source, such as a
semiconductor laser or a sufficiently powerful filtered white light source. The source shall
produce sufficient radiation at the intended wavelength(s) and be stable in intensity over a
time period sufficient to perform the measurement.
A monochromator or interference filter(s) may be used, if required, for wavelength selection.
The detail specification shall specify the wavelength of the source. The full width half
maximum (FWHM) spectral line width of the source shall be less than or equal to 10 nm,
unless otherwise specified.
See Annex D for method D.
IEC 60793-1-45:2017 © IEC 2017 – 9 –
6.3 Input optics
For method A, B, and C, an optical lens system or fibre pigtail may be employed to excite the
specimen. It is recommended that the power coupled into the specimen be relatively
insensitive to the position of its input end face. This can be accomplished by using a launch
beam that spatially and angularly overfills the input end face.
If using a butt splice, employ index-matching material between the fibre pigtail and the
specimen to avoid interference effects. The coupling shall be stable for the duration of the
measurement.
See Annex D for method D.
6.4 Input positioner
Provide means of positioning the input end of the specimen to the light source. Examples
include the use of x-y-z micropositioner stages, or mechanical coupling devices such as
connectors, vacuum splices, three-rod splices. The position of the fibre shall remain stable
over the duration of the measurement.
6.5 Cladding mode stripper
Use a device that extracts cladding modes. Under some circumstances, the fibre coating will
perform this function.
6.6 High-order mode filter
Use a means to remove high-order propagating modes in the wavelength range that is greater
than or equal to the cut-off wavelength of the specimen. For example, a one-turn bend with a
radius of 30 mm on the fibre is generally sufficient for most B1.1 to B6 fibres. For some B6
fibres, smaller radius, multiple bends or longer specimen length can be applied to remove
high-order propagating modes.
6.7 Output positioner
Provide a suitable means for aligning the fibre output end face in order to allow an accurate
axial adjustment of the output end, such that, at the measurement wavelength, the scan
pattern is suitably focused on the plane of the scanning detector. Such coupling may include
the use of lenses, or may be a mechanical connector to a detector pigtail.
Provide means such as a side-viewing microscope or camera with a crosshair to locate the
fibre at a fixed distance from the apertures or detectors. It may be sufficient to provide only
longitudinal adjustment if the fibre is constrained in the lateral plane by a device such as a
vacuum chuck (this depends mainly upon the size of the light detector).
6.8 Output optics
See the appropriate annex: A, B, C or D.
6.9 Detector
See the appropriate annex: A, B, C or D.
6.10 Computer
Use a computer to perform operations such as controlling the apparatus, taking intensity
measurements, and processing the data to obtain the final results. For individual details, see
the appropriate annex: A, B, C or D.

– 10 – IEC 60793-1-45:2017 © IEC 2017
7 Sampling and specimens
7.1 Specimen length
For methods A, B and C, the specimen shall be a known length, typically 2 m ± 0,2 m for most
B1.1 to B6 fibres. For some B6 fibres, longer specimen length can be used to avoid high-order
propagating modes, 22 m for example.
For method D, OTDR, the sample shall be long enough to exceed (or be positioned beyond)
the dead zone of the OTDR, with both ends accessible, as described in the backscatter test
method IEC 60793-1-40.
7.2 Specimen end face
Prepare a flat end face, orthogonal to the fibre axis, at the input and output ends of each
specimen.
8 Procedure
See Annexes A, B, C and D for methods A, B, C and D, respectively.
9 Calculations
9.1 Basic equations
The basic equations for calculating mode field diameter by methods A, B and C are given
below. For additional calculations, see the appropriate annex: A, B, C or D. Sample data sets
for methods A, B and C are included in Annex E.
9.2 Method A – Direct far-field scan
The following equation defines the mode field diameter for method A in terms o
...