IEC 63267-2-2:2024

IEC 63267-2-2 ®
Edition 1.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre optic interconnecting devices and passive components – Connector
optical interfaces for enhanced macro bend multimode fibres –
Part 2-2: Connection parameters of physically contacting 50 μm core diameter
fibres – Non-angled and angled for reference connector applications

Dispositifs d'interconnexion et composants passifs fibroniques – Interfaces
optiques de connecteurs pour fibre multimodale à performances améliorées par
macrocourbures –
Partie 2-2: Paramètres de connexion de fibres de diamètre de cœur de 50 µm en
contact physique – Fibres inclinées et non inclinées pour les applications de
connecteurs de référence
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IEC 63267-2-2 ®
Edition 1.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre optic interconnecting devices and passive components – Connector

optical interfaces for enhanced macro bend multimode fibres –

Part 2-2: Connection parameters of physically contacting 50 μm core diameter

fibres – Non-angled and angled for reference connector applications

Dispositifs d'interconnexion et composants passifs fibroniques – Interfaces

optiques de connecteurs pour fibre multimodale à performances améliorées par

macrocourbures –
Partie 2-2: Paramètres de connexion de fibres de diamètre de cœur de 50 µm en

contact physique – Fibres inclinées et non inclinées pour les applications de

connecteurs de référence
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.20  ISBN 978-2-8322-8416-2

– 2 – IEC 63267-2-2:2024 © IEC 2024
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Performance grades . 6
5 Description . 6
6 Criteria for a fit within the performance grade . 7
7 Attenuation measurement uncertainty contribution . 7
8 Visual inspection . 7
Annex A (informative) Multimode attenuation measurement uncertainty contribution . 9
A.1 General . 9
A.2 Sources of variability. 9
A.2.1 Measurement condition and setup . 9
A.2.2 Geometry mismatch . 9
A.3 Overall uncertainty . 10
Annex B (informative) Test limits for performance grade B connectors against grade
m
R reference connectors . 12
m
B.1 General . 12
B.2 Test limits . 12
Bibliography . 13

Figure 1 – Geometrical requirements for fibre core location after termination . 7
Figure A.1 – Attenuation measurement uncertainty contribution for Grade R
m1
reference connections resulting from lateral offset, NA and CD mismatch . 9

Table 1 – Attenuation grades for multimode reference connections at 850 nm . 6
Table 2 – Lateral offset values for grade R reference connections . 7
m
Table 3 – Visual requirements for multimode PC and APC polished connection . 8
Table A.1 – Evaluation of the uncertainty contribution due measurement conditions . 11
Table B.1 – Performance grade test limits at 850 nm . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC INTERCONNECTING DEVICES AND PASSIVE
COMPONENTS – CONNECTOR OPTICAL INTERFACES FOR
ENHANCED MACRO BEND MULTIMODE FIBRES –

Part 2-2: Connection parameters of physically contacting
50 μm core diameter fibres – Non-angled and angled for
reference connector applications

FOREWORD
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IEC 63267-2-2 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.
– 4 – IEC 63267-2-2:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
86B/4857/FDIS 86B/4878/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/publications.
A list of all parts in the IEC 63267 series, published under the general title Fibre optic
interconnecting devices and passive components – Connector optical interfaces for enhanced
macro bend multimode fibre, can be found on the IEC website.
Future documents in this series will carry the new general title as cited above. Titles of existing
documents in this series will be updated at the time of the next edition.
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• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
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of its contents. Users should therefore print this document using a colour printer.

FIBRE OPTIC INTERCONNECTING DEVICES AND PASSIVE
COMPONENTS – CONNECTOR OPTICAL INTERFACES FOR
ENHANCED MACRO BEND MULTIMODE FIBRES –

Part 2-2: Connection parameters of physically contacting
50 μm core diameter fibres – Non-angled and angled for
reference connector applications

1 Scope
This part of IEC 63267 defines the dimensional limits of an optical interface for reference
connections necessary to meet specific requirements for fibre-to-fibre interconnection of non-
angled and angled polished multimode reference connectors intended to be used for attenuation
measurements in the field or factory.
Several grades of reference connections are defined in this document. The multimode reference
connections are terminated to restricted IEC 60793-2-10 A1-OM2b to A1-OM5b fibre at the
850 nm band only. The geometrical dimensions and tolerances of the specified reference
connections have been developed primarily to limit the variation in measured attenuation
between multiple sets of two reference connectors, and therefore to limit the variation in
measured attenuation between randomly chosen reference connectors when mated with
connectors in the field or factory.
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 60793-2-10, Optical fibres – Part 2-10: Product specifications – Sectional specification for
category A1 multimode fibres
IEC 61300-3-35, 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
3 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

– 6 – IEC 63267-2-2:2024 © IEC 2024
4 Performance grades
This document currently specifies several performance grades.
The performance grade for physical contact non-angled (PC) and angled (APC) polished fibre-
to-fibre reference connections detailed in this document is shown in Table 1.
The attenuation is measured in accordance with IEC 61300-3-4 (insertion method B).
The attenuation test limit of reference grade connectors mated with standard grade B
m
connectors is provided in Annex B.
Table 1 – Attenuation grades for multimode reference connections at 850 nm
Reference grade Attenuation
[dB]
R ≤ 0,1
m1
R ≤ 0,15
m12
R ≤ 0,15
m16
R ≤ 0,15
m16A
R ≤ 0,15
m24
R ≤ 0,15
m32
NOTE 1 Grade R reference connection applies to 1,25 mm and 2,5 mm single
m1
fibre cylindrical ferrules while all other reference grades apply to multifibre
rectangular ferrules.
NOTE 2 The number in the designation of the reference grade indicates the number
of fibres in the reference connector. The letter “A” indicates an angled physical
contact interface.
NOTE 3 As described in Annex A, the contribution to measurement uncertainty in
attenuation measurement between any connector according to the IEC optical
interface standards in the 63267 series and a population of IEC reference connectors
is for all performance grades ± 0,071 dB.

5 Description
Optical reference connections are connections manufactured with restricted tolerances on
dimensions that contribute to lateral and angular offset of mating fibre cores. These connections
are mainly used for attenuation measurement purposes in field and factory and shall be
considered as part of the measurement setup. The goal is to strongly reduce the measurement
uncertainty. The attenuation uncertainties due to the reference connections are defined in this
document and are discussed in Annex A.
The performance of a multimode optical interface is not only determined by the alignment
accuracy of the optical datum targets of two mating fibres, but largely by any fibre parameter
mismatches. Parameters influencing the fibre-to-fibre intrinsic attenuation include:
• core diameter (CD) mismatch,
• numerical aperture (NA) mismatch.

6 Criteria for a fit within the performance grade
Figure 1 and Table 2 give the criteria for meeting the performance grades as listed in Table 1.
The parameters that are selected for the criteria definition are based on their degree of
significance in affecting the performance.
All R multimode reference connections shall be terminated on selected multimode (MM)
m
A1-OM2b to A1-OM5b fibre, as specified in IEC 60793-2-10, with a core diameter of
50 µm ± 0,5 µm and a numerical aperture of 0,200 ± 0,002. The selection is required to restrict
the variability of attenuation measurements using reference connectors.

Figure 1 – Geometrical requirements for fibre core location after termination
Table 2 – Lateral offset values for grade R reference connections
m
a
F [µm]
Reference grade Minimum Maximum
R
m1
R
m12
R
m16
0 1,0
R
m16A
R
m24
R
m32
a
Parameter F defines the core location of a reference connector in relation to the
optical datum target (Figure 1). In addition, parameter F describes also the
maximum lateral offset between the fibre cores of two mated reference connectors.
NOTE Lateral offset of R grades for rectangle ferrules consists of both the fibre
m
true position on the ferrule and the relative ferrule position from guide pin and bore
fitting.
7 Attenuation measurement uncertainty contribution
Using the specified fibre geometry and the dimensional tolerances mentioned in Clause 6, it is
possible to achieve measurements using the specified reference connections that have an
uncertainty of ±0,071 dB, with random varied reference connections and with the target EF
launch as specified in IEC 61300-1 satisfied (see Annex A).
8 Visual inspection
The fibre end faces of all reference grade variants shall be inspected to IEC 61300-3-35 and
shall meet the requirements as detailed in Table 3. The zone size for multimode fibres has been
set at 65 µm. This has been done to simplify the grading process.

– 8 – IEC 63267-2-2:2024 © IEC 2024
Table 3 – Visual requirements for multimode PC and APC polished connection
Zone Defects Scratches
(diameter) (diameter) (width)
< 2 µm: no limit < 3 µm: no limit
A: core zone
≥ 2 µm and ≤ 5 µm: maximum 4 ≥ 3 µm and ≤ 4 µm: maximum 4
65 µm
> 5 µm: none > 4 µm: none
B: cladding zone ≤ 25 µm: no limit
No limit
65 µm to 110 µm > 25 µm: none
Annex A
(informative)
Multimode attenuation measurement uncertainty contribution
A.1 General
The attenuation of a multimode connectorised component (or connector) based on a cylindrical
ferrule is measured against an R reference connector in a reference adapter and when based
m1
on rectangular ferrules against the relevant pinned/unpinned R to R reference connector.
m12 m32
Since reference connection parts vary within the tolerances allowed in this document, the
variability has to be considered as a contribution to the attenuation measurement uncertainty
of the setup.
A.2 Sources of variability
A.2.1 Measurement condition and setup
Measurement condition and setup variability are caused by factors such as power meter
calibration, finite display resolution, linearity, connector/detector coupling repeatability, source
stability and launch conditions. IEC TR 62627-04 gives a more detailed explanation of how to
determine this uncertainty for single mode fibres and it can be adapted for use with MM
connections.
A.2.2 Geometry mismatch
Another factor causing variability is the mismatch between the fibre geometry parameters of the
reference connector and the DUT connector, such as core diameter (CD), numerical aperture
(NA) and lateral offset. For the calculation, worst case mismatch is used assuming that the DUT
fibre has a CD of 47,5 µm and a NA of 0,185. The calculated uncertainty also depends on the
offset between the fibre cores of reference and DUT plugs. See Figure A.1.

Figure A.1 – Attenuation measurement uncertainty contribution for Grade R
m1
reference connections resulting from lateral offset, NA and CD mismatch

– 10 – IEC 63267-2-2:2024 © IEC 2024
The red line presents the averaged result of a Monte Carlo Simulation (MCS) of the calculated
attenuation of a DUT plug with a worst-case minimal CD and NA (47,5 µm and 0,185 NA) mated
to 6 000 Grade R reference connectors.
m1
The blue line presents the averaged result of the MCS of the calculated attenuation of a DUT
plug with nominal CD and NA (50 µm and 0,200 NA) mated to 6 000 Grade R reference
m1
connectors.
The red and blue bars show the calculated range of values for the different lateral offsets; the
black bars are 95 % of the calculated variation representing the range for uncertainty.
The calculated average attenuation for the DUT plug with nominal core diameter and nominal
NA fibre is much lower (approximately 0,5 dB) than for the DUT plug with minimal CD and
minimal NA fibre. The calculated variation (bars) is also much smaller.
The worst-case variability due to geometry mismatch between reference connections and the
DUT is 0,17 dB.
The uncertainty U is 0,17 dB/ 2 = 0,085 dB.
Geo
A.3 Overall uncertainty
The overall measurement uncertainty is calculated from Table A.1 which is an adaptation of the
tables provided in IEC TR 62627-04 for multimode fibre.

Table A.1 – Evaluation of the uncertainty contribution due measurement conditions
c d
Error Probability Standard Sensitivity Uncertainty
Uncertainty Divisor
a, b d e f
contribution
coefficient
source distribution uncertainty
i X u u u(x ) c u (y)
i i i i
(dB) (%)
(%) (%)
u
1 0,005 0,12 rect 1,732 1 0,07 √2 0,10
TypeA
u
2 0,08 1,84 rect 1,732 1 1,06 1 1,06
MMLC
u
3 0,005 0,12 rect 1,732 1 0,07 √2 0,10
Displ
u
4 0,005 0,12 normal 1 0,12 1 0,12
Lin
u
5 0,02 0,46 rect 1,732 1 0,27 1 0,27
Unif
u
6 0,01 0,23 rect 1,732 1 0,13 √2 0,19
Pstab
u
7 0,05 1,16 rect 1,732 1 0,67 1 0,67
mating
U
8 0,085 1,96 normal 2 0,98 1 0,98
Geo
1,63 %
uu
∑ i
0,071 dB
i=1
a
The uncertainty values listed in Table A.1 are, when applicable, values of IEC TR 62627-04. Refer to the
IEC 62614 series for uncertainty value due to multimode launch conditions.
b
Definition of the error sources is, when applicable, the same as IEC TR 62627-04:2012, 4.2. Definition of
error due to multimode launch conditions, u , is the same as IEC TR 61282-14:2019, 5.2.5.3. U is
MMLC Geo
defined in A.2.2. The errors have been estimated in dB and were then transformed into a percentage for all
further calculations.
c
Probability distributions are estimated for single measurements to be rectangular. For rectangular probability
distributions the uncertainty should be divided by √3 = 1,7321.
d
Standard uncertainty is obtained by dividing the uncertainty by the divisor.
e
Sensitivity coefficient is obtained directly from IEC TR 62627-04:2012, 4.2, Formula (2) and
IEC TR 61282-14:2019, Table 5.
f
The values have been rounded up to get conservative results.

Therefore, the expanded uncertainty at 95 % confidence level (k = 2) is: U = 2 u = 0,142 dB.

==
– 12 – IEC 63267-2-2:2024 © IEC 2024
Annex B
(informative)
Test limits for performance grade B connectors
m
against grade R reference connectors
m
B.1 General
Annex B provides information on the test limits for performance grade B connectors against
m
grade R reference connectors. The use of reference connectors is not normative but if
m
reference connectors are used, for example in case of quality conformance, the specified
maximum attenuation limits in Table B.1 are normative.
B.2 Test limits
The performance grade for PC and APC polished fibre-to-fibre reference connections detailed
in this document are shown in Table B.1.
The attenuation is measured in accordance with IEC 61300-3-4 (insertion method B).
Table B.1 – Performance grade test limits at 850 nm
Reference grade Attenuation [dB] Attenuation test limit [dB]
reference connection to grade R reference connection
m
reference connection
to standard grade B conn
...