oSIST prEN IEC 61755-2-4:2026

SLOVENSKI STANDARD
01-marec-2026
Optični spojni elementi in pasivne komponente - Vmesniki optičnih konektorjev - 2
-4. del: Parametri povezave enorodovnih fizično dotikajočih se vlaken z
nepremaknjeno disperzijo - Nekotni za aplikacije referenčnih konektorjev
Fibre optic interconnecting devices and passive components - Connector optical
interfaces - Part 2-4: Connection parameters of non-dispersion shifted single-mode
physically contacting fibres - Non-angled for reference connection applications
Ta slovenski standard je istoveten z: prEN IEC 61755-2-4:2026
ICS:
33.180.20 Povezovalne naprave za Fibre optic interconnecting
optična vlakna devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

86B/5169/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61755-2-4 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-01-16 2026-04-10
SUPERSEDES DOCUMENTS:
86B/5093/CD, 86B/5126A/CC
IEC SC 86B : FIBRE OPTIC INTERCONNECTING DEVICES AND PASSIVE COMPONENTS
SECRETARIAT: SECRETARY:
Japan Mr Ryo Koyama
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
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TITLE:
Fibre optic interconnecting devices and passive components - Connector optical interfaces - Part 2-
4: Connection parameters of non-dispersion shifted single-mode physically contacting fibres - Non-
angled for reference connection applications

PROPOSED STABILITY DATE: 2033
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IEC CDV 61755-2-4 © IEC 2026
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IEC CDV 61755-2-4 © IEC 2026
CONTENTS
Contact . 2
CONTENTS . 3
FOREWORD . 4
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Performance grades . 7
5 Description . 8
6 Criteria for a fit within performance grades . 8
6.1 General . 8
6.2 Attenuation grades and criteria . 8
7 Attenuation measurement uncertainty contribution . 10
8 Visual requirements for return loss grade . 11
Annex A (informative) Single-mode attenuation measurement uncertainty contribution . 12
A.1 Introduction . 12
A.2 Sources of variability . 12
A.3 Example determination of attenuation measurement uncertainty . 12
Annex B (informative) Test limits for performance grade B connectors against grade 1
reference connectors . 14
B.1 General . 14
B.2 Test limits . 14
Annex C (informative) Effect of damaged surface layer on non-angled connections . 15
Bibliography . 17

Figure 1 – Representation of fibre core position of single connection under the
assumption of worst-case alignment with identical connection . 10
Figure A.1 – Attenuation measurement uncertainty contribution for Grade 1 reference
connectors . 12
Figure C.1 – Model of the connection of convex polished end faces under compressive
load 15
Figure C.2 – High index layer refractive index and thickness versus return loss for a
typical dispersion unshifted single-mode fibre . 16

Table 1 – Single-mode attenuation grades . 8
Table 2 – Single-mode return loss grades . 8
Table 3 – Mode field diameter and fibre core nominal index of refraction for fibre to be
used in reference connections . 9
Table 4 – Visual requirements for single-mode PC polished reference connections . 11
Table B.1 – Performance grade test limits at 1 310 nm . 14

IEC CDV 61755-2-4 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Fibre optic interconnecting devices and passive components - Connector
optical interfaces -
Part 2-4: Connection parameters of non-dispersion shifted single-mode
physically contacting fibres - Non-angled for reference connection
applications
FOREWORD
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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.
IEC CDV 61755-2-4 © IEC 2026
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/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 61755-2-4 has been prepared by subcommittee 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) Correction to the title;
b) Update to be inclusive of IEC 60793-2-50 class B fibres with restricted mode field diameter
(MFD);
c) Added terms and definitions clause;
d) Modification of performance grade naming conventions to include "Grade 1" and "Grade 2"
which is also used in ISO/IEC 14763-3 [1];
e) Inclusion of return loss grades;
f) Clear definition of the applicable wavelengths;
g) Removed ferrule diameter information in Clause 5 since this belongs in a Part 3 document;
h) Remove Clause 6 "Use of selected fibre to assemble reference connector plugs" as this was
redundant information;
i) Remove Clause 7 "Reference adaptor" as this should be described in Part 3 documents;
j) Removed Table 3 since measurement uncertainty contribution is included in Table 1;
k) Addition of visual requirements for return loss grade (Clause 8);
l) Retitled Annex A to "Single-mode attenuation measurement uncertainty contribution",
included introduction and sources of variability clauses;
m) New informative Annex B, which describes performance limits for grade 1 connectors when
tested to random grade B connectors;
n) New informative Annex C, which describes the damage layer's impact on return loss;
o) New Bibliography.
The text of this International Standard is based on the following documents:
Draft Report on voting
XX/XX/FDIS XX/XX/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 [change
language if necessary].
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.
IEC CDV 61755-2-4 © IEC 2026
The French version of this standard has not been voted upon.
A list of all parts in the IEC 61755 series, published under the general title Fibre optic
interconnecting devices and passive components -Connector optical interfaces, can be found
on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
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 CDV 61755-2-4 © IEC 2026
1 Scope
This part of IEC 61755 defines the dimensional limits of an optical interface for reference
connections necessary to meet specific requirements for fibre-to-fibre interconnection of non-
angled single-mode reference connectors intended to be used for attenuation measurements in
the field or factory.
Two different grades for reference connections are defined in this document. The use of each
of these grades depends on the application and on the targeted attenuation measurement
uncertainty. The single-mode reference connections are terminated to IEC 60793-2-50 class B
fibre with restricted mode field diameter (MFD). The geometrical dimensions and tolerances of
the specified reference connections have been developed primarily to limit t
...