IEC 61280-4-1:2009

Fibre-optic communication subsystem test procedures - Part 4-1: Installed cable plant - Multimode attenuation measurement

IEC 61280-4-1:2009 is applicable to the measurement of attenuation of installed fibre-optic cabling using multimode fibre, typically in lengths of up to 2 000 m. This cabling can include multimode fibres, connectors, adapters and splices. In this standard, the fibre types that are addressed include category A1a (50/125 µm) and A1b (62,5/125 µm) multimode fibres, as specified in IEC 60793-2-10. The attenuation measurements of the other multimode categories can be made, using the approaches of this standard, but the source conditions for the other categories have not been defined. The main changes with respect to the previous edition are:
- An additional measurement method based on optical time domain reflectometry (OTDR) is documented, with guidance on best practice in using the OTDR and interpreting OTDR traces.
- The requirement for the sources used to measure multimode fibres is changed from one based on coupled power ratio (CPR) and mandrel requirement to one based on measurements of the near field at the output of the launching test cord.
- Highlighting the importance of, and giving guidance on, good measurement practices including cleaning and inspection of connector end faces.

Procédures d'essai des sous-systèmes de télécommunication à fibres optiques - Partie 4-1: Installations câblées - Mesure de l'affaiblissement en multimodal

La CEI 61280-4-1:2009 s'applique à la mesure de l'affaiblissement d'une installation de câblage en fibre optique utilisant des fibres multimodes, généralement sur des longueurs allant jusqu'à 2 000 m. Cette installation de câblage peut inclure des fibres multimodes, des connecteurs, des raccords et des épissures. Dans la présente norme, les types de fibres abordées comportent les fibres multimodes de catégorie A1a (50/125 µm) et A1b (62,5/125 µm) spécifiées dans la CEI 60793-2-10. Les mesures d'affaiblissement des autres catégories multimodales peuvent être effectuées en utilisant les approches de la présente norme, mais les conditions de source des autres catégories n'ont pas été définies. Les principales modifications portant sur cette précédente édition sont:
- Une méthode de mesure supplémentaire basée sur la réflectométrie optique dans le domaine temporel (OTDR) est rapportée, avec des indications sur les meilleures pratiques d'utilisation de l'OTDR et d'interprétation des tracés de l'OTDR.
- L'exigence concernant les sources utilisées pour mesurer les fibres multimodes passe d'une exigence basée sur le taux de puissance couplée (CPR) et l'exigence relative au mandrin à une exigence basée sur des mesures en champ proche à la sortie du cordon d'essai d'amorce.
- La mise en valeur de l'importance et la fourniture de directives sur de bonnes pratiques de mesure incluant le nettoyage et l'examen des faces d'extrémité des connecteurs.

General Information

• Status: Published
• Publication Date: 09-Jun-2009
• ICS: 33.180.01 - Fibre optic systems in general
• Technical Committee: SC 86C - Fibre optic systems and active devices
• Drafting Committee: WG 1 - TC 86/SC 86C/WG 1
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 22-May-2019

Relations

• Revised: IEC 61280-4-1:2019 - Fibre-optic communication subsystem test procedures - Part 4-1: Installed cabling plant - Multimode attenuation measurement
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61280-4-1


®

Edition 2.0 2009-06



INTERNATIONAL



STANDARD





Fibre-optic communication subsystem test procedures –
Part 4-1: Installed cable plant – Multimode attenuation measurement




IEC 61280-4-1:2009(E)

---------------------- Page: 1 ----------------------
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IEC 61280-4-1


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Edition 2.0 2009-06



INTERNATIONAL



STANDARD





Fibre-optic communication subsystem test procedures –
Part 4-1: Installed cable plant – Multimode attenuation measurement



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– 2 – 61280-4-1 © IEC:2009(E)



CONTENTS

FOREWORD.5


1 Scope.7

2 Normative references .7

3 Terms, definitions, graphical symbols and acronyms .8


3.1 Terms and definitions .8

3.2 Graphical symbols.9

3.3 Acronyms .11

4 Measurement methods .11
4.1 General .11
4.2 Cabling configurations and applicable test methods .12
4.3 Overview of uncertainties .12
4.3.1 General .12
4.3.2 Test cords .13
4.3.3 Launch conditions at the connection to the cabling under test .13
4.3.4 Optical source .13
4.3.5 Output power reference .13
4.3.6 Received power reference .14
5 Apparatus.14
5.1 General .14
5.2 Light source .14
5.2.1 Stability .14
5.2.2 Spectral characteristics .14
5.2.3 Launch cord .14
5.3 Receive or tail cord .15
5.4 Substitution/dummy cord .15
5.5 Power meter – LSPM methods only .15
5.6 OTDR apparatus .15
5.7 Connector end-face cleaning and inspection equipment .16
5.8 Adapters .16
6 Procedures.16
6.1 General .16
6.2 Common procedures .17

6.2.1 Care of the test cords .17
6.2.2 Make reference measurements (LSPM methods only) .17
6.2.3 Inspect and clean the ends of the fibres in the cabling.17
6.2.4 Make the measurements.17
6.2.5 Make the calculations .17
6.3 Calibration.17
6.4 Safety .17
7 Calculations .17
8 Documentation .18
8.1 Information for each test.18
8.2 Information to be available .18
Annex A (normative) One-cord reference method.19
Annex B (normative) Three-cord reference method .21

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61280-4-1 © IEC:2009(E) – 3 –


Annex C (normative) Two-cord reference method .23

Annex D (normative) Optical time domain reflectometer.26


Annex E (normative) Requirements for the source characteristics for multimode

measurement.32

Annex F (informative) Measurement uncertainty examples.35

Annex G (informative) OTDR configuration information .44


Annex H (informative) Test cord insertion loss verification .53

Bibliography.61



Figure 1a – Socket and plug assembly.10
Figure 1b – Connector set (plug, adapter, plug) .10
Figure 1c – Light source .10
Figure 1d – Power meter.10
Figure 1 – Connector symbols .10
Figure 2 – Symbol for cabling under test.10
Figure 3 – OTDR schematic .16
Figure A.1 − Reference measurement.20
Figure A.2 − Test measurement .20
Figure B.1 − Reference measurement.22
Figure B.2 − Test measurement .22
Figure C.1 − Reference measurement.24
Figure C.2 − Test measurement.24
Figure C.3 – Test measurement for plug-socket style connectors.24
Figure D.1 − Test measurement for Method D.27
Figure D.2 − Location of the cabling under test ports .28
Figure D.3 − Graphic construction of F and F .29
1 2
Figure D.4 − Graphic construction of F , F , F and F .30
1 11 12 2
Figure E.1 – Encircled flux template example.33
Figure F.1 – Initial power measurement .37
Figure F.2 – Verification of reference grade connection .38
Figure F.3 – Two offset splices .38

Figure F.4 – Five offset splices .38
Figure F.5 – EF centred .40
Figure F.6 – EF underfilling.40
Figure F.7 – EF overfilling.41
Figure F.8 – L1 loss with mandrel .41
Figure F.9 – L1 loss with mandrel and mode conditioner.42
Figure F.10 – L2 loss (adjusted) with mandrel.42
Figure F.11 – L2 loss (adjusted) with mandrel and mode conditioning.42
Figure F.12 – L3 loss (adjusted) with mandrel.43
Figure F.13 – L3 loss (adjusted) with mandrel and mode conditioning.43
Figure G.1 − Splice and macro bend attenuation measurement.47
Figure G.2 − Attenuation measurement with high reflection connectors.48

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Figure G.3 − Attenuation measurement of a short length cabling.49


Figure G.4 − OTDR trace with ghost .50

Figure G.5 − Cursors positioning.51

Figure H.1 − Obtaining reference power level P .54
0

Figure H.2 − Obtaining power level P .55
1

Figure H.3 − Obtaining reference power level P .56
0

Figure H.4 − Obtaining power level P .56

1

Figure H.5 − Obtaining reference power level P .57
0

Figure H.6 − Obtaining power level .57
Figure H.7 − Obtaining reference power level P .58
0
Figure H.8 − Obtaining power level P .58
1
Figure H.9 − Obtaining power level P .58
5
Figure H.10 − Obtaining reference power level P .59
0
Figure H.11 − Obtaining power level P .59
1

Table 1 – Cabling configurations.12
Table 2 – Test methods and configurations.12
Table 3 – Spectral requirements .14
Table E.1 – Threshold tolerance .33
Table E.2 – EF requirements for 50 μm core fibre cabling at 850 nm .34
Table E.3 – EF requirements for 50 μm core fibre cabling at 1 300 nm .34
Table E.4 – EF requirements for 62,5 μm core fibre cabling at 850 nm .34
Table E.5 – EF requirements for 62,5 μm core fibre cabling at 1 300 nm.34
Table F.1 – Expected loss for examples (note 1).35
Table G.1 – Default effective group index of refraction values.46

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61280-4-1 © IEC:2009(E) – 5 –


INTERNATIONAL ELECTROTECHNICAL COMMISSION

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FIBRE-OPTIC COMMUNICATION SUBSYSTEM

TEST PROCEDURES –



Part 4-1: Installed cable plant –

Multimode attenuation measurement





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
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 61280-4-1 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
This second edition cancels and replaces the first edition, published in 2003, and constitutes
a technical revision.
The main changes with respect to the previous edition are listed below:
– An additional measurement method based on optical time domain reflectometry
(OTDR) is documented, with guidance on best practice in using the OTDR and
interpreting OTDR traces.
– The requirement for the sources used to measure multimode fibres is changed from
one based on coupled power ratio (CPR) and mandrel requirement to one based on
measurements of the near field at the output of the launching test cord.

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– 6 – 61280-4-1 © IEC:2009(E)


– Highlighting the importance of, and giving guidance on, good measurement practices

including cleaning and inspection of connector end faces.


The text of this standard is based on the following documents:


FDIS Report on voting

86C/879/FDIS 86C/892/RVD



Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.


This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 61280 series, under the general title Fibre-optic
communication subsystem test procedure, can be found on the IEC website.
For the Part 4, the new subtitle will be Installed cable plant. Subtitles 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 publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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61280-4-1 © IEC:2009(E) – 7 –


FIBRE-OPTIC COMMUNICATION SUBSYSTEM

TEST PROCEDURES –



Part 4-1: Installed cable plant –

Multimode attenuation measurement








1 Scope

This part of IEC 61280-4 is applicable to the measurement of attenuation of installed fibre-
optic cabling using multimode fibre, typically in lengths of up to 2 000 m. This cabling can
include multimode fibres, connectors, adapters and splices.
Cabling design standards such as ISO/IEC 11801, ISO/IEC 24702 and ISO/IEC 24764 contain
specifications for this type of cabling. ISO/IEC 14763-3, which supports these design
standards, makes reference to the test methods of this standard.
In this standard, the fibre types that are addressed include category A1a (50/125 μm) and A1b
(62,5/125 μm) multimode fibres, as specified in IEC 60793-2-10. The attenuation
measurements of the other multimode categories can be made, using the approaches of this
standard, but the source conditions for the other categories have not been defined.
2 Normative references
The following referenced documents are indispensable for the application 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
(OFCS)
IEC 61280-1-3, Fibre optic communication subsystem basic test procedures – Part 1-3: Test
procedures for general communication subsystems – Central wavelength and spectral width
measurement
IEC 61280-1-4, Fibre optic communication subsystem test procedures – Part 1-4: General
1
communication subsystems – Light source encircled flux measurement method

IEC 61300-3-35, Fibre optic interconnecting devices and passive components − Basic test
and measurement procedures − Part 3-35: Examinations and measurements − Fibre optic
cylindrical connector endface visual inspection
IEC 61315, Calibration of fibre-optic power meters
IEC 61745, End-face image analysis procedure for the calibration of optical fibre geometry
test sets
IEC 61746, Calibration of optical time-domain reflectometers (OTDRs)
—————————
1
 A new edition is in preparation.

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– 8 – 61280-4-1 © IEC:2009(E)


3 Terms, definitions, graphical symbols and acronyms


For the purposes of this document, the following terms, definitions, graphical symbols and

acronyms apply.


3.1 Terms and definitions


3.1.1

attenuation

reduction of optical power induced by transmission through a medium such as cabling, given

as L (dB)

L = 10 log (P /P )
10 in out
where P and P are the power, typically measured in mW, into and out of the cabling
in out
3.1.2
light source power meter
LSPM
test system consisting of a light source (LS), power meter (PM) and associated test cords
used to measure the attenuation of installed cable plant
3.1.3
optical time domain reflectometer
OTDR
test system consisting of an optical time-domain reflectometer and associated test cords used
to characterize and measure the attenuation of installed cable plant and specific elements
within that cable plant
3.1.4
test cord
terminated optical fibre cord used to connect the optical source or detector to the cabling, or
to provide suitable interfaces to the cabling under test
NOTE There are five types of test cords:
– launch cord: used to connect the light source to the cabling;
– receive cord: used to connect the cabling to the power meter (LSPM only);
– tail cord: attached to the far end of the cabling when an OTDR is used at the near end. This provides a means
of evaluating attenuation of the whole of the cabling including the far end connection;
– adapter cord: used to transition between sockets or other incompatible connectors in a required test
configuration;
– substitution cord: a test cord used within a reference measurement which is replaced during the measurement

of the loss of the cabling under test.
3.1.5
bidirectional measurement
two measurements of the same optical fibre, made by launching light into opposite ends of
that fibre
3.1.6
configuration
form or arrangements of parts or elements such as terminations, connections and splices
3.1.7
encircled flux
EF
fraction of cumulative near field power to total output power as a function of radial distance
from the optical centre of the core

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61280-4-1 © IEC:2009(E) – 9 –


[from IEC 61280-1-4]


3.1.8

reference grade termination

connector (3.1.9) plug (3.1.10) with tightened tolerances terminated onto an optical fibre with

tightened tolerances such that the expected loss of a connection formed by mating two such

assemblies is less than or equal to 0,1 dB


EXAMPLE: as an example, the core diameter tolerance may need to be ±0,7 micron (ffs).
Other fibre tolerances are ffs.

NOTE 1 An adapter (3.1.11), required to assure this performance, may be considered to be part of the reference
grade termination where required by the test configuration (3.1.6)
NOTE 2 This definition remains as a point under study. When a more complete definition is available in another
document, this definition will be replaced by a reference.
3.1.9
connector
component normally attached to an optical cable or piece of apparatus, for the purpose of
providing frequent optical interconnection/disconnection of optical fibres or cables
{Definition 2.6.1 of IEC/TR 61931}
3.1.10
plug
male-type part of a connector
[Definition 2.6.2 of IEC/TR 61931]
3.1.11
adapter
female-part of a connector in which one or two plugs are inserted and aligned
[Definition 2.6.4 of IEC/TR 61931:1998]
3.1.12
socket-style connector
connector for which the adapter, including any alignment device, is integrated with, and
permanently attached to the connector plug on one side of the connection
NOTE Examples include the SG and many harsh environment connectors.
3.1.13

reference test method
RTM
test method used in the resolution of a dispute
3.2 Graphical symbols
The following graphic symbols for different connection options have been adapted from
IEC 61930.

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– 10 – 61280-4-1 © IEC:2009(E)





a

c




d

IEC  924/09
b


IEC  923/09


Figure 1a – Socket and plug assembly Figure 1b – Connector set (plug, adapter, plug)
PM
P
1
LS

IEC  926/09
IEC  925/09

Figure 1c – Light source Figure 1d – Power meter
Key
a  socket d  plug inserted into plug-adapter assembly
b  plug LS light source
c plug-adapter assembly PM power meter
Figure 1 – Connector symbols
NOTE 1 In Figure 1b, and elsewhere in this standard, the plugs are shown with different sizes to indicate
directionality where the cabling has adapters pre-attached and the test cord does not, or vice versa. In Figure 1b,
the plug on the left has the adapter pre-attached.
NOTE 2 Reference grade terminations are shown shaded with grey.


IEC  927/09

Figure 2 – Symbol for cabling under test
In the figures that illustrate the measurement configurations in Annexes A through D, the
cabling under test is illustrated by a loop as shown in Figure 2. Although illustrated as just a
loop of fibre, it may contain additional splices and connectors in addition to the terminal
connectors. Note that for purposes of measuring the attenuation of this cabling, the losses
associated with the terminal connectors are considered separately from the cabling itself.

---------------------- Page: 12 ----------------------
61280-4-1 © IEC:2009(E) – 11
...

IEC 61280-4-1


®

Edition 2.0 2009-06



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
colour
inside


Fibre-optic communication subsystem test procedures –
Part 4-1: Installed cable plant – Multimode attenuation measurement

Procédures d'essai des sous-systèmes de télécommunication
à fibres optiques –
Partie 4-1: Installations câblées – Mesure de l'affaiblissement en multimodal


IEC 61280-4-1:2009

---------------------- Page: 1 ----------------------
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IEC 61280-4-1


®

Edition 2.0 2009-06



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
colour
inside


Fibre-optic communication subsystem test procedures –
Part 4-1: Installed cable plant – Multimode attenuation measurement

Procédures d'essai des sous-systèmes de télécommunication
à fibres optiques –
Partie 4-1: Installations câblées – Mesure de l'affaiblissement en multimodal


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 33.180.01 ISBN 978-2-88912-046-8
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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CONTENTS

FOREWORD.5


1 Scope.7

2 Normative references .7

3 Terms, definitions, graphical symbols and acronyms .8


3.1 Terms and definitions .8

3.2 Graphical symbols.9

3.3 Acronyms .11

4 Measurement methods .11
4.1 General .11
4.2 Cabling configurations and applicable test methods .12
4.3 Overview of uncertainties .12
4.3.1 General .12
4.3.2 Test cords .13
4.3.3 Launch conditions at the connection to the cabling under test .13
4.3.4 Optical source .13
4.3.5 Output power reference .13
4.3.6 Received power reference .14
5 Apparatus.14
5.1 General .14
5.2 Light source .14
5.2.1 Stability .14
5.2.2 Spectral characteristics .14
5.2.3 Launch cord .14
5.3 Receive or tail cord .15
5.4 Substitution/dummy cord .15
5.5 Power meter – LSPM methods only .15
5.6 OTDR apparatus .15
5.7 Connector end-face cleaning and inspection equipment .16
5.8 Adapters .16
6 Procedures.16
6.1 General .16
6.2 Common procedures .17

6.2.1 Care of the test cords .17
6.2.2 Make reference measurements (LSPM methods only) .17
6.2.3 Inspect and clean the ends of the fibres in the cabling.17
6.2.4 Make the measurements.17
6.2.5 Make the calculations .17
6.3 Calibration.17
6.4 Safety .17
7 Calculations .17
8 Documentation .18
8.1 Information for each test.18
8.2 Information to be available .18
Annex A (normative) One-cord reference method.19
Annex B (normative) Three-cord reference method .21

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Annex C (normative) Two-cord reference method .23

Annex D (normative) Optical time domain reflectometer.26


Annex E (normative) Requirements for the source characteristics for multimode

measurement .32

Annex F (informative) Measurement uncertainty examples.35

Annex G (informative) OTDR configuration information .44


Annex H (informative) Test cord insertion loss verification .53

Bibliography.61



Figure 1a – Socket and plug assembly.10
Figure 1b – Connector set (plug, adapter, plug) .10
Figure 1c – Light source .10
Figure 1d – Power meter.10
Figure 1 – Connector symbols .10
Figure 2 – Symbol for cabling under test.10
Figure 3 – OTDR schematic .16
Figure A.1 − Reference measurement.20
Figure A.2 − Test measurement .20
Figure B.1 − Reference measurement.22
Figure B.2 − Test measurement .22
Figure C.1 − Reference measurement.24
Figure C.2 − Test measurement.24
Figure C.3 – Test measurement for plug-socket style connectors.24
Figure D.1 − Test measurement for Method D.27
Figure D.2 − Location of the cabling under test ports .28
Figure D.3 − Graphic construction of F and F .29
1 2
Figure D.4 − Graphic construction of F , F , F and F .30
1 11 12 2
Figure E.1 – Encircled flux template example.33
Figure F.1 – Initial power measurement .37
Figure F.2 – Verification of reference grade connection .38
Figure F.3 – Two offset splices .38

Figure F.4 – Five offset splices .38
Figure F.5 – EF centred .40
Figure F.6 – EF underfilling.40
Figure F.7 – EF overfilling.41
Figure F.8 – L1 loss with mandrel .41
Figure F.9 – L1 loss with mandrel and mode conditioner.42
Figure F.10 – L2 loss (adjusted) with mandrel.42
Figure F.11 – L2 loss (adjusted) with mandrel and mode conditioning.42
Figure F.12 – L3 loss (adjusted) with mandrel.43
Figure F.13 – L3 loss (adjusted) with mandrel and mode conditioning.43
Figure G.1 − Splice and macro bend attenuation measurement.47
Figure G.2 − Attenuation measurement with high reflection connectors.48

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Figure G.3 − Attenuation measurement of a short length cabling.49


Figure G.4 − OTDR trace with ghost .50

Figure G.5 − Cursors positioning.51

Figure H.1 − Obtaining reference power level P .54
0

Figure H.2 − Obtaining power level P .55
1

Figure H.3 − Obtaining reference power level P .56
0

Figure H.4 − Obtaining power level P .56

1

Figure H.5 − Obtaining reference power level P .57
0

Figure H.6 − Obtaining power level .57
Figure H.7 − Obtaining reference power level P .58
0
Figure H.8 − Obtaining power level P .58
1
Figure H.9 − Obtaining power level P .58
5
Figure H.10 − Obtaining reference power level P .59
0
Figure H.11 − Obtaining power level P .59
1

Table 1 – Cabling configurations.12
Table 2 – Test methods and configurations.12
Table 3 – Spectral requirements .14
Table E.1 – Threshold tolerance .33
Table E.2 – EF requirements for 50 μm core fibre cabling at 850 nm .34
Table E.3 – EF requirements for 50 μm core fibre cabling at 1 300 nm .34
Table E.4 – EF requirements for 62,5 μm core fibre cabling at 850 nm .34
Table E.5 – EF requirements for 62,5 μm core fibre cabling at 1 300 nm.34
Table F.1 – Expected loss for examples (note 1).35
Table G.1 – Default effective group index of refraction values.46

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61280-4-1 © IEC:2009 – 5 –


INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



FIBRE-OPTIC COMMUNICATION SUBSYSTEM

TEST PROCEDURES –



Part 4-1: Installed cable plant –

Multimode attenuation measurement





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 61280-4-1 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
This second edition cancels and replaces the first edition, published in 2003, and constitutes
a technical revision.
The main changes with respect to the previous edition are listed below:
– An additional measurement method based on optical time domain reflectometry
(OTDR) is documented, with guidance on best practice in using the OTDR and
interpreting OTDR traces.
– The requirement for the sources used to measure multimode fibres is changed from
one based on coupled power ratio (CPR) and mandrel requirement to one based on
measurements of the near field at the output of the launching test cord.

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– Highlighting the importance of, and giving guidance on, good measurement practices

including cleaning and inspection of connector end faces.


This bilingual version (2010-07) replaces the English version.


The text of this standard is based on the following documents:


FDIS Report on voting

86C/879/FDIS 86C/892/RVD


Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 61280 series, under the general title Fibre-optic
communication subsystem test procedure, can be found on the IEC website.
For the Part 4, the new subtitle will be Installed cable plant. Subtitles 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 publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication 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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FIBRE-OPTIC COMMUNICATION SUBSYSTEM

TEST PROCEDURES –



Part 4-1: Installed cable plant –

Multimode attenuation measurement








1 Scope

This part of IEC 61280-4 is applicable to the measurement of attenuation of installed fibre-
optic cabling using multimode fibre, typically in lengths of up to 2 000 m. This cabling can
include multimode fibres, connectors, adapters and splices.
Cabling design standards such as ISO/IEC 11801, ISO/IEC 24702 and ISO/IEC 24764 contain
specifications for this type of cabling. ISO/IEC 14763-3, which supports these design
standards, makes reference to the test methods of this standard.
In this standard, the fibre types that are addressed include category A1a (50/125 μm) and A1b
(62,5/125 μm) multimode fibres, as specified in IEC 60793-2-10. The attenuation
measurements of the other multimode categories can be made, using the approaches of this
standard, but the source conditions for the other categories have not been defined.
2 Normative references
The following referenced documents are indispensable for the application 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
(OFCS)
IEC 61280-1-3, Fibre optic communication subsystem basic test procedures – Part 1-3: Test
procedures for general communication subsystems – Central wavelength and spectral width
measurement
IEC 61280-1-4, Fibre optic communication subsystem test procedures – Part 1-4: General
communication subsystems – Light source encircled flux measurement method

IEC 61300-3-35, Fibre optic interconnecting devices and passive components − Basic test
and measurement procedures − Part 3-35: Examinations and measurements − Fibre optic
cylindrical connector endface visual inspection
IEC 61315, Calibration of fibre-optic power meters
IEC 61745, End-face image analysis procedure for the calibration of optical fibre geometry
test sets
IEC 61746, Calibration of optical time-domain reflectometers (OTDRs)

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3 Terms, definitions, graphical symbols and acronyms


For the purposes of this document, the following terms, definitions, graphical symbols and

acronyms apply.


3.1 Terms and definitions


3.1.1

attenuation

reduction of optical power induced by transmission through a medium such as cabling, given

as L (dB)

L = 10 log (P /P )
10 in out
where P and P are the power, typically measured in mW, into and out of the cabling
in out
3.1.2
light source power meter
LSPM
test system consisting of a light source (LS), power meter (PM) and associated test cords
used to measure the attenuation of installed cable plant
3.1.3
optical time domain reflectometer
OTDR
test system consisting of an optical time-domain reflectometer and associated test cords used
to characterize and measure the attenuation of installed cable plant and specific elements
within that cable plant
3.1.4
test cord
terminated optical fibre cord used to connect the optical source or detector to the cabling, or
to provide suitable interfaces to the cabling under test
NOTE There are five types of test cords:
– launch cord: used to connect the light source to the cabling;
– receive cord: used to connect the cabling to the power meter (LSPM only);
– tail cord: attached to the far end of the cabling when an OTDR is used at the near end. This provides a means
of evaluating attenuation of the whole of the cabling including the far end connection;
– adapter cord: used to transition between sockets or other incompatible connectors in a required test
configuration;
– substitution cord: a test cord used within a reference measurement which is replaced during the measurement

of the loss of the cabling under test.
3.1.5
bidirectional measurement
two measurements of the same optical fibre, made by launching light into opposite ends of
that fibre
3.1.6
configuration
form or arrangements of parts or elements such as terminations, connections and splices
3.1.7
encircled flux
EF
fraction of cumulative near field power to total output power as a function of radial distance
from the optical centre of the core

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[from IEC 61280-1-4]


3.1.8

reference grade termination

connector (3.1.9)
...