IEC 61300-3-35:2022

IEC 61300-3-35
®

Edition 3.0 2022-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside


Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures –
Part 3-35: Examinations and measurements – Visual inspection of fibre optic
connectors and fibre-stub transceivers

Dispositifs d’interconnexion et composants passifs fibroniques – Procédures
fondamentales d’essais et de mesures –
Partie 3-35: Examens et mesures – Examen visuel des connecteurs fibroniques
et des émetteurs-récepteurs à embase fibrée

IEC 61300-3-35:2022-09(en-fr)

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IEC 61300-3-35

®


Edition 3.0 2022-09




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside










Fibre optic interconnecting devices and passive components – Basic test and

measurement procedures –

Part 3-35: Examinations and measurements – Visual inspection of fibre optic


connectors and fibre-stub transceivers



Dispositifs d’interconnexion et composants passifs fibroniques – Procédures


fondamentales d’essais et de mesures –

Partie 3-35: Examens et mesures – Examen visuel des connecteurs fibroniques

et des émetteurs-récepteurs à embase fibrée










INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 33.180.20 ISBN 978-2-8322-5713-5




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® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – IEC 61300-3-35:2022 © IEC 2022
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 7
4 Apparatus . 7
4.1 General . 7
4.2 Method A: Direct view optical microscopy . 8
4.3 Method B: Video microscopy . 8
4.4 Method C: Automated analysis microscopy . 9
4.5 Requirements of validation . 9
4.6 Minimum requirements for standard field of view microscope . 9
4.7 Minimum requirements for large field of view microscope . 9
5 Inspection procedure . 9
Annex A (normative) Visual requirements for connector end faces . 12
A.1 Requirements . 12
A.2 Visual inspection requirements for multimode PC and APC polished
connectors . 12
A.3 Visual requirements for single-mode PC polished connectors, RL ≥ 26 dB,
and single-mode transceivers using a fibre-stub interface . 13
A.4 Visual requirements for single-mode PC polished connectors, RL ≥ 35 dB . 13
A.5 Visual requirements for single-mode PC polished connectors, RL ≥ 45 dB . 14
A.6 Visual requirements for single-mode angle polished (APC) connectors . 14
Annex B (informative) Examples of defects and scratches . 15
Annex C (normative) Validation procedure . 16
C.1 Validation artefact . 16
C.2 Validation procedure . 16
Annex D (informative) Recommended cleaning method. 17
D.1 Inspection procedure for cleanliness . 17
D.2 Cleaning procedure rectangular ferrules (on cable) . 17
D.3 Cleaning procedure for cylindrical ferrules . 19
D.4 Cleaning procedure for adaptor and receptacle of rectangular ferrules . 20
Annex E (informative) Examples of large field of view images . 21
Bibliography . 23

Figure 1 – Flowchart of inspection procedure . 10
Figure B.1 – Example 1 of defects and scratches . 15
Figure B.2 – Example 2 of defects and scratches . 15
Figure D.1 – Flowchart of dry only cleaning/inspection sequence . 17
Figure D.2 – Flowchart of dry-wet cleaning/inspection sequence . 17
Figure D.3 – Dry cleaning of connector on cable . 18
Figure D.4 – Moisten the tape . 19
Figure D.5 – Wiping action . 19

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IEC 61300-3-35:2022 © IEC 2022 – 3 –
Figure D.6 – cleaning of cylindrical ferrule . 19
Figure D.7 – Moisten the tape . 20
Figure D.8 – 2 Strokes on wet tape . 20
Figure D.9 – Insert click cleaner. 20
Figure D.10 – Clean pins . 20
Figure D.11 – Rotate stick . 20
Figure E.1 – Example of typical contaminations . 21
Figure E.2 – Example of typical contaminations . 21
Figure E.3 – Example of typical contaminations . 22
Figure E.4 – Example of typical contaminations . 22

Table A.1 – Visual requirements for multimode PC and APC polished connectors . 12
Table A.2 – Visual requirements for single-mode PC polished connectors, RL ≥ 26 dB,
and single-mode transceivers using a fibre-stub interface . 13
Table A.3 – Visual requirements for single-mode PC polished connectors, RL ≥ 35 dB . 13
Table A.4 – Visual requirements for single-mode PC polished connectors, RL ≥ 45 dB . 14
Table A.5 – Visual requirements for single-mode angle polished (APC) connectors . 14

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– 4 – IEC 61300-3-35:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

FIBRE OPTIC INTERCONNECTING DEVICES AND PASSIVE
COMPONENTS – BASIC TEST AND MEASUREMENT PROCEDURES –

Part 3-35: Examinations and measurements – Visual inspection
of fibre optic connectors and fibre-stub transceivers

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
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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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.
IEC 61300-3-35 has been prepared by subcommittee SC 86B: Fibre optic interconnecting
devices and passive components, of IEC technical committee 86: Fibre optics. It is an
International Standard.
This third edition cancels and replaces the second edition published in 2015. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) adding of a statement that visual inspection is not a substitute for optical qualification such
as attenuation and return loss measurement;
b) adding of some terms and definitions;
c) adding requirements for SM 35 dB connectors;

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IEC 61300-3-35:2022 © IEC 2022 – 5 –
d) adding of a sentence in Clause 5 concerning the susceptibility of the methods to system
variability and variability within systems from same supplier;
e) removal of inspection requirements for zones C and D;
f) insertion of a generic cleanliness specification for whole rectangular ferrule and 250 µm
area around every fibre;
g) adding a cleaning recommendation for rectangular and cylindrical ferrules;
h) outer edge of inspection zone B has changed from 115 µm to 110 µm to meet manufacturing
tolerances of fixture for microscopes;
i) change that defects that are partly in core are only to be judged for the part they are in the
core. The remainder of the defect is considered to be located in the cladding.
j) adding a statement that a connector cannot be rejected by just failing visual inspection.
Meeting the specified optical performance determines the use of this connector.
The text of this International Standard is based on the following documents:
Draft Report on voting
86B/4643/FDIS 86B/4665/RVD

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/standardsdev/publications.
A list of all parts in the IEC 61300 series, published under the general title Fibre optic
interconnecting devices and passive components – Basic test and measurement procedures,
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,
• replaced by a revised edition, or
• amended.

IMPORTANT – The "colour inside" logo on the cover page of this document 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.

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– 6 – IEC 61300-3-35:2022 © IEC 2022
FIBRE OPTIC INTERCONNECTING DEVICES AND PASSIVE
COMPONENTS – BASIC TEST AND MEASUREMENT PROCEDURES –

Part 3-35: Examinations and measurements – Visual inspection
of fibre optic connectors and fibre-stub transceivers



1 Scope
This part of IEC 61300 is concerned with the observation and classification of debris, scratches
and defects. The inspection requirements are based on IEC TR 62627-05. Advice for cleaning
of contamination from fibres/ferrule is found in IEC TR 62627-01 and a recommendation is given
in Annex D. IEC TR 62572-4 provides the cleaning method for a stub for optical transceivers.
Visual inspection is in addition to, and does not replace measurement of performance
parameters such as attenuation and return loss, or end face parameters. The dimensions
specified are chosen such that they can be easily estimated. Not only the zones A and B on the
fibre are inspected for defects and scratches but the whole contact area (where the two
fibres/ferrules meet when mated) needs to be inspected for contamination (this is up to 250 µm
diameter for cylindrical ferrules and the whole ferrule surface for rectangular ferrules).
The objectives of this document are the following:
• specify the minimum criteria for a microscope to be compliant to this document;
• specify the procedure and criteria for inspecting fibre-optic end faces for cleanliness to
determine if the end faces are fit for use. All connector optical interfaces (IEC 61755 series
and IEC 63267 series) are based on physical contact between fibre cores;
• provide quantitative criteria for the analysis of end face images.
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 60825-2, Safety of laser products – Part 2 Safety of optical fibre communication systems
(OFCSs)
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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

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IEC 61300-3-35:2022 © IEC 2022 – 7 –
3.1.1
defect
permanent non-linear surface feature on the fibre or ferrule end face within the regions of
interest, which includes, but it not limited to, pits, chips, edge chipping, and/or non removable
foreign material
Note 1 to entry: Some fibre types have structural features potentially visible on the fibre end face. Fibres that use
microstructures to contain the light signal, such as photonic band-gap and hole-assisted fibres, can have an
engineered or random pattern of structures surrounding the core. These features are not defects.
Note 2 to entry: Scratches are excluded from this definition.
3.1.2
defect size
diameter of the smallest circle that can encompass the entire defect
3.1.3
debris
unwanted material or particulates of any kind on the surface of fibre or ferrule end face within
the regions of interest that is removeable using standard cleaning methods
Note 1 to entry: Multiple cleaning methods are described in IEC TR 62627-01.
3.1.4
scratch
permanent surface feature on the fibre end face where the width of the damaged area is smaller
than or equal to one fifth of its length
3.1.5
reliably detectable
sufficiently clear and visible so that a typical technician of average training would recognize a
feature at least 98 % of the time
3.2 Abbreviated terms
APC angled physical contact
DUT device under test
FOV field of view
LFOV large field of view
MM multimode
PC physical contact
RL return loss
SFOV standard field of view
SM single-mode
4 Apparatus
4.1 General
One of the objectives of this document is to specify the minimum criteria (see 4.5 and 4.6) a
microscope shall meet to be compliant to this document.
Three types of microscopes are described:
a) method A microscope: direct view optical microscope as described in 4.2;
b) method B microscope: video microscope as described in 4.3;
c) method C microscope: automated analysis microscope as described in 4.4.

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For each type, there are optical/hardware requirements to be met and procedures to be
followed. As these processes are in support of the inspection criteria defined in Clause 5, all
three are expected to result in a "pass" or "fail".
The minimum optical requirements for all types of microscopes to be compliant with this
document are given in 4.5 and 4.6.
The microscopes described in this document, with the exception of large field of view (LFOV),
are capable of being used for inspection for contamination (cleanliness) prior mating in the field
and factory and after polishing SM and MM, single-fibre and multifibre connectors in the factory.
LFOV microscopes can be used for inspection of contamination of the entire ferrule surface of
multifibre connectors in the field and in the factory.
For methods A and B, visual gauge tools should be used to facilitate the estimation procedure.
For method A, an eyepiece reticule should be used. For method B, a transparent overlay should
be used.
WARNING – All methods are susceptible to system variability: methods A and B are operator
and equipment hardware dependent. Method C is less operator dependent but exhibits from
software irregularities and variations in hardware and, in case of field use, operator handling
differences can cause a variation in results that might appear even when equipment from the
same brand is compared. Method C has an inherent uncertainty when defects or scratches are
located near test limits, as described in Annex A tables.
4.2 Method A: Direct view optical microscopy
This method uses an optical microscope in which a primary objective lens forms a first image
that is then magnified by an eyepiece that projects the image directly to the user’s eye. It shall
have the following features and capabilities:
• a suitable ferrule or connector adapter;
• a light source and focussing mechanism;
• a built-in laser safety filter;
• a means to compare dimension of defects or scratches observed in the image with a
sufficient reliability (i.e. eyepiece reticule with certified dimension according the
magnification).
Laser safety is of particular concern when using direct view microscopes, as any energy in the
optical path is directed into the eye of the observer. When method A is used, the user shall
ensure there is no laser active on the link prior to inspection. IEC 60825-2 shall be used for
laser safety of optical fibre communication systems.
4.3 Method B: Video microscopy
This method uses an optical microscope in which a lens system forms an image on a sensor
that, in turn, transfers the image to a display. The user views the image on the display. It shall
have the following features and capabilities:
• a suitable ferrule or connector adapter;
• a light source and focussing mechanism;
• a means for creating an image (display);
• a means to estimate surface dimensions defects and/or scratches observed in the image
(e.g. overlay with certified dimension according the image on the screen).

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IEC 61300-3-35:2022 © IEC 2022 – 9 –
4.4 Method C: Automated analysis microscopy
This method uses an optical microscope in which a digital image is acquired or created and is
subsequently analysed via an algorithmic process. The purpose of such a system is to reduce
the effects of human subjectivity in the analysis process. It shall have the following features
and capabilities:
• a suitable ferrule or connector adapter;
• a light source and focussing mechanism;
• a means for acquiring and creating a digital image;
• algorithmic analysis of the digital image;
• a means to compare the analysed image to programmable acceptance criteria.
4.5 Requirements of validation
Microscope systems for methods A, B and C shall be validated for use as compliant with this
document. This validation shall be conducted with a purpose-built validation artefact that can
serve to validate a system’s ability to detect surface defects or scratches of relevant size and/or
the required system response. Such (an) artefact(s) shall be provided with instructions on its
use and shall be manufactured in a method such that it can be measured in a traceable manner.
The related validation procedure is found in Annex C.
4.6 Minimum requirements for standard field of view microscope
This requirement for the standard field of view microscope (SFOV) is a minimum total
magnification offering a field of view of at least 250 µm (for methods B and C, this dimension
shall be measured in the vertical, or most constrained axis) capable of detecting defects of
2 µm in diameter and scratches of 3 µm wide in the whole field of view.
The minimum requirements for systems for methods A, B and C are as follows:
• particle size detection: 2 µm diameter;
• scratch detection: 3 µm wide.
4.7 Minimum requirements for large field of view microscope
Microscopes with large field of view are only capa
...