SIST EN IEC 60793-1-45:2024

Optical fibres - Part 1-45: Measurement methods and test procedures - Mode field diameter

IEC 60793-1-45:2024 is available as IEC 60793-1-45:2024 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60793-1-45:2024 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. This third edition cancels and replaces the second edition published in 2017. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) modification of the minimum distance between the fibre end and the detector for the direct far field scan (Annex A).
b) generalization of the requirement for the minimum dynamic range for all fibre types (Annex A).

Lichtwellenleiter - Teil 1-45: Messmethoden und Prüfverfahren - Modenfelddurchmesser

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

IEC 60793-1-45:2024 est disponible sous forme de IEC 60793-1-45:2024 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.

L'IEC 60793-1-45:2024 établit des exigences harmonisées pour mesurer le diamètre du champ de mode (MFD, Mode Field Diameter) d’une fibre optique unimodale, contribuant ainsi au contrôle des fibres et câbles à des fins commerciales. Cette troisième édition annule et remplace la deuxième édition parue en 2017. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) modification de la distance minimale entre l’extrémité de la fibre et le détecteur pour l’exploration directe en champ lointain (Annexe A),
b) généralisation de l’exigence de plage dynamique minimale pour tous les types de fibres (Annexe A).

Optična vlakna - 1-45. del: Merilne metode in postopki preskušanja - Premer osnovnega rodu

Ta del standarda IEC 60793 določa enotne zahteve za merjenje premera osnovnega redu (MFD) enorodnih optičnih vlaken, pri čemer pomaga pri pregledu vlaken in kablov za komercialne namene.

General Information

• Status: Published
• Public Enquiry End Date: 22-Jun-2023
• Publication Date: 10-Jun-2024
• ICS: 33.180.10 - Fibres and cables
• Technical Committee: MOC - Mobile Communications
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 05-Jun-2024
• Due Date: 10-Aug-2024
• Completion Date: 11-Jun-2024
• Ref Project: EN IEC 60793-1-45:2024 - Optical fibres - Part 1-45: Measurement methods and test procedures - Mode field diameter

Relations

• Replaces: SIST EN IEC 60793-1-45:2018 - Optical fibres - Part 1-45: Measurement methods and test procedures - Mode field diameter (IEC 60793-1-45:2017)
• Effective Date: 01-Jul-2024

Overview

EN IEC 60793-1-45:2024 (IEC 60793-1-45:2024) specifies standardized measurement methods and test procedures for Mode Field Diameter (MFD) of single‑mode optical fibre. This third edition (2024) replaces the 2017 edition and is published as an RLV (International Standard with Redline showing technical changes). The standard establishes uniform requirements to support reliable MFD measurement for commercial inspection, quality control and product specification.

Key Topics and Requirements

• Scope: MFD measurement methods for single‑mode optical fibre and the procedures to obtain repeatable, comparable results.
• Reference and normative methods: Four principal measurement methods are defined:
  • Method A: Direct far‑field scan (detailed in Annex A)
  • Method B: Variable aperture in the far field (Annex B)
  • Method C: Near‑field scan (Annex C)
  • Method D: Optical Time Domain Reflectometer (OTDR) based method (Annex D)
• Apparatus and components: Requirements for light sources, input/output optics, positioners, detectors, cladding‑mode strippers, high‑order mode filters and data acquisition/computer systems.
• Sampling and sample prep: Guidance on sample length and end‑face quality to ensure measurement validity.
• Procedures and calculations: Step‑by‑step procedures and calculation methods including centroid determination, folded power curves, complementary aperture functions and integral computations to derive MFD.
• Results and reporting: What information must be reported by each method and optional data available on request.
• Technical revisions in 2024:
  • Modified minimum distance between fibre end and detector for the direct far‑field scan (Annex A).
  • Generalized minimum dynamic range requirement applicable to all fibre types (Annex A).

Applications and Who Uses It

EN IEC 60793-1-45:2024 is essential for:

• Optical fibre manufacturers - for product development, acceptance testing and specification compliance.
• Test laboratories and certification bodies - to provide traceable, standardized MFD measurements.
• Cable and component producers (connectors, splices) - to ensure interoperability and performance (mode‑field matching).
• Telecommunications and data‑center operators - for network qualification, loss budgeting and OTDR calibration.
• R&D teams and academic labs - for reproducible optical characterizations of single‑mode fibres.

Practical use cases include factory QA, incoming inspection, supplier verification, and validation of connector/splice loss predictions based on MFD compatibility.

Related Standards

• IEC 60793‑1‑40 / EN IEC 60793‑1‑40 - Optical fibres: attenuation measurement methods (referenced normative standard).
• Other parts of the IEC 60793 series covering physical and optical properties of fibres.

Keywords: Mode field diameter, MFD measurement methods, single‑mode optical fibre testing, EN IEC 60793-1-45:2024, IEC 60793-1-45, optical fibre standards, MFD test procedures.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2024
Optična vlakna - 1-45. del: Merilne metode in postopki preskušanja - Premer
osnovnega rodu
Optical fibres - Part 1-45: Measurement methods and test procedures - Mode field
diameter
Lichtwellenleiter - Teil 1-45: Messmethoden und Prüfverfahren - Modenfelddurchmesser
Fibres optiques - Partie 1-45 : Méthodes de mesure et procédures d'essai - Diamètre du
champ de mode
Ta slovenski standard je istoveten z: EN IEC 60793-1-45:2024
ICS:
33.180.10 (Optična) vlakna in kabli 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 May 2024
ICS 33.180.10 Supersedes EN IEC 60793-1-45:2018
English Version
Optical fibres - Part 1-45: Measurement methods and test
procedures - Mode field diameter
(IEC 60793-1-45:2024)
Fibres optiques - Partie 1-45 : Méthodes de mesure et Lichtwellenleiter - Teil 1-45: Messmethoden und
procédures d'essai - Diamètre du champ de mode Prüfverfahren - Modenfelddurchmesser
(IEC 60793-1-45:2024) (IEC 60793-1-45:2024)
This European Standard was approved by CENELEC on 2024-05-24. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye 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
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60793-1-45:2024 E

European foreword
The text of document 86A/2300/CDV, future edition 3 of IEC 60793-1-45, 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 60793-1-45:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-02-24
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-05-24
document have to be withdrawn
This document supersedes EN IEC 60793-1-45:2018 and all of its amendments and corrigenda (if
any).
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.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60793-1-45:2024 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 60793-2 NOTE Approved as EN IEC 60793-2
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.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60793-1-40 - Optical fibres - Part 1-40: Attenuation EN IEC 60793-1-40 -
measurement methods
IEC 60793-1-45 ®
Edition 3.0 2024-04
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 978-2-8322-8639-5

– 2 – IEC 60793-1-45:2024 © IEC 2024
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 7
4 General consideration about mode field diameter . 8
5 Reference test method . 8
6 Apparatus . 8
6.1 General . 8
6.2 Light source . 9
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 . 10
6.9 Detector . 10
6.10 Computer . 10
7 Sampling and samples . 10
7.1 Sample length . 10
7.2 Sample end face . 10
8 Procedure . 10
9 Calculations . 10
9.1 Basic formulae . 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 . 12
10 Results . 13
10.1 Information available with each measurement . 13
10.2 Information available upon request . 13
11 Specification information . 13
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. 15
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 Formula (1) . 15
A.3.3 Complete the calculation . 16
A.4 Sample data . 16
Annex B (normative) Requirements specific to method B – Mode field diameter by
variable aperture in the far field . 17

IEC 60793-1-45:2024 © IEC 2024 – 3 –
B.1 Apparatus . 17
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 . 21
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 . 23
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 – Orientation and notation . 25
D.4 Calculations . 26
D.4.1 Reference fibre mode field diameter . 26
D.4.2 Computation of the sample 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
Bibliography . 31

Figure 1 – Transform relationships between measurement results . 8
Figure A.1 – Far-field measurement set . 14

– 4 – IEC 60793-1-45:2024 © IEC 2024
Figure B.1 – Variable aperture by far-field measurement set . 17
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 1 – Abbreviated terms . 7
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 60793-1-45:2024 © IEC 2024 – 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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60793-1-45 has been prepared by subcommittee 86A: Fibres and cables, of IEC technical
committee 86: Fibre optics. It is an International Standard.
This third edition cancels and replaces the second edition published in 2017. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Modification of the minimum distance between the fibre end and the detector for the direct
far field scan (Annex A).
b) Generalization of the requirement for the minimum dynamic range for all fibre types
(Annex A).
– 6 – IEC 60793-1-45:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2300/CDV 86A/2366/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IEC 60793-1-45:2024 © IEC 2024 – 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, Optical fibres – Part 1-40: Attenuation measurement methods
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.2 Abbreviated terms
The abbreviated terms are given in Table 1.
Table 1 – Abbreviated terms
Abbreviated term Full term
CCD charge-coupled devices
FWHM full width half maximum
MFD mode field diameter
OTDR optical time domain reflectometer
RTM reference test method
– 8 – IEC 60793-1-45:2024 © IEC 2024
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 Formula (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.

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 Clause 1 to Clause 11, and information
pertaining to each individual method appears in Annex A, Annex B, Annex C, and Annex 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. Annex A, Annex B, Annex C,
and Annex D include layout drawings and other equipment requirements for each of the four
methods, respectively.
IEC 60793-1-45:2024 © IEC 2024 – 9 –
6.2 Light source
For method A, method B and method C, use a suitable coherent or non-coherent light source,
such as a semiconductor laser or a powerful filtered white light source.
A monochromator or interference filter(s) may be used, if required, for wavelength selection.
The detail specification shall indicate the wavelength of the source. The full width half maximum
(FWHM) spectral line width of the source shall ≤10 nm, unless otherwise specified.
The source power level shall be chosen so it is not impacting the repeatability of the mode
diameter measurement.
The source power shall be stable for the complete duration of the measurement.
See Annex D for method D.
6.3 Input optics
For method A, method B, and method C, an optical lens system or fibre pigtail may be employed
to excite the sample. It is recommended that the power coupled into the sample 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 sample
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 sample to the light source. Examples include
the use of x-y-z micropositioner stages, or mechanical coupling devices such as connectors,
vacuum splices,or 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 sample. For example, a one-turn bend with a
radius of 30 mm on the fibre is generally sufficient for most B-652, B-653, B-654, B-655, B-656
and B-657 fibres. For some B-657 fibres, smaller radius, multiple bends, or longer sample 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 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 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 can 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).

– 10 – IEC 60793-1-45:2024 © IEC 2024
6.8 Output optics
See the appropriate annex: Annex A, Annex B, Annex C or Annex D.
6.9 Detector
See the appropriate annex: Annex A, Annex B, Annex C or Annex D.
6.10 Computer
Use a computer to perform operations such as controlling the apparatus, takin
...