SIST EN 61280-2-9:2009

SLOVENSKI STANDARD
01-julij-2009
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Fibre optic communication subsystem test procedures - Part 2-9: Digital systems -
Optical signal-to-noise ratio measurement for dense wavelength-division multiplexed
systems (IEC 61280-2-9:2009)
Prüfverfahren für Lichtwellenleiter-Kommunikationsuntersysteme - Teil 2-9: Digitale
Systeme - Messung des optischen Signal-Rausch-Verhältnisses für dichte Wellenlängen
-Multiplex-Systeme (IEC 61280-2-9:2009)
Procédures d'essai des sous-systèmes de télécommunications à fibres optiques - Partie
2-9: Systèmes numériques - Mesure du rapport signal sur bruit optique pour les
systèmes multiplexés à répartition en longueur d'onde dense (CEI 61280-2-9:2009)
Ta slovenski standard je istoveten z: EN 61280-2-9:2009
ICS:
33.180.20 3RYH]RYDOQHQDSUDYH]D Fibre optic interconnecting
RSWLþQDYODNQD devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61280-2-9
NORME EUROPÉENNE
April 2009
EUROPÄISCHE NORM
ICS 33.180.20 Supersedes EN 61280-2-9:2002

English version
Fibre optic communication subsystem test procedures -
Part 2-9: Digital systems -
Optical signal-to-noise ratio measurement
for dense wavelength-division multiplexed systems
(IEC 61280-2-9:2009)
Procédures d'essai des sous-systèmes  Prüfverfahren für Lichtwellenleiter-
de télécommunications à fibres optiques - Kommunikationsuntersysteme -
Partie 2-9: Systèmes numériques - Teil 2-9: Digitale Systeme -
Mesure du rapport signal sur bruit optique Messung des optischen
pour les systèmes multiplexés Signal-Rausch-Verhältnisses für dichte
à répartition en longueur d'onde dense Wellenlängen-Multiplex-Systeme
(CEI 61280-2-9:2009) (IEC 61280-2-9:2009)

This European Standard was approved by CENELEC on 2009-04-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: avenue Marnix 17, B - 1000 Brussels

© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61280-2-9:2009 E
Foreword
The text of document 86C/823/CDV, future edition 2 of IEC 61280-2-9, prepared by SC 86C, Fibre optic
systems and active devices, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote
and was approved by CENELEC as EN 61280-2-9 on 2009-04-01.
This European Standard supersedes EN 61280-2-9:2002.
The main changes from EN 61280-2-9:2002 are as follows:
– a paragraph has been added to the scope describing the limitations due to signal spectral width and
wavelength filtering;
– Annex B has been added to further explain error in measuring noise level due to signal spectral width
and wavelength filtering.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2010-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2012-04-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61280-2-9:2009 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 61280-2-9:2009
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

1) 2)
IEC 61290-3-1 - Optical amplifiers - Test methods - EN 61290-3-1 2003
Part 3-1: Noise figure parameters - Optical
spectrum analyzer method
1) 2)
IEC 62129 - Calibration of optical spectrum analyzers EN 62129 2006
+ corr. December 2006
1)
Undated reference.
2)
Valid edition at date of issue.

IEC 61280-2-9 ®
Edition 2.0 2009-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fibre optic communication subsystem test procedures –
Part 2-9: Digital systems – Optical signal-to-noise ratio measurement for dense
wavelength-division multiplexed systems

Procédures d'essai des sous-systèmes de télécommunications
à fibres optiques –
Partie 2-9: Systèmes numériques – Mesure du rapport signal sur bruit optique
pour les systèmes multiplexés à répartition en longueur d'onde dense

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
S
CODE PRIX
ICS 33.180.20 ISBN 2-8318-1029-1
– 2 – 61280-2-9 © IEC:2009
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .8
3 Definition.8
4 Apparatus.9
4.1 General .9
4.2 Diffraction grating-based OSA .9
4.3 Michelson interferometer-based OSA .10
4.4 Fabry-Perot-based OSA .10
4.5 OSA performance requirements .11
4.5.1 General .11
4.5.2 Wavelength range .11
4.5.3 Sensitivity.11
4.5.4 Resolution bandwidth (RBW) .11
4.5.5 Resolution bandwidth accuracy .12
4.5.6 Dynamic range .12
4.5.7 Scale fidelity.13
4.5.8 Polarization dependence .13
4.5.9 Wavelength data points .13
5 Sampling and specimens.13
6 Procedure .13
7 Calculations .14
8 Measurement uncertainty .14
9 Documentation .14
Annex A (informative) Error in measuring signal level due to signal spectral width.16
Annex B (informative) Error in measuring noise level due to signal spectral width and
wavelength filtering.19
Bibliography.21

Figure 1 – A typical optical spectrum at an optical interface in a multichannel
transmission system .8
Figure 2 – The OSNR for each channel as derived from direct measurements of the
optical spectrum .9
Figure 3 – A diffraction grating-based OSA .10
Figure 4 – A Michelson interferometer-based OSA.10
Figure 5 – A Fabry-Perot-based OSA.11
Figure 6 – Illustration of insufficient dynamic range as another source of measurement
uncertainty.
Figure A.1 – The power spectrum of a 10 Gb/s, 2 − 1 PRBS signal showing the
considerable amount of power not captured in a 0,1 nm RBW with 0,64 nm filtering
after the signal.17
Figure A.2 – The spectrum of a 2,5 Gb/s 2 − 1 PRBS with 0,36 nm filtering with
considerably less power outside the 0,1 nm OSA RBW .
Figure A.3 – Signal power error versus RBW for a 10 Gb/s modulated signal.18

61280-2-9 © IEC:2009 – 3 –
Figure A.4 – Signal power error versus RBW for a 2,5 Gb/s modulated signal.18
Figure B.1 – Example for noise filtering between channels for a 200 GHz grid .20

Table A.1 – Filtering used in simulation to determine signal power level error.16
Table A.2 – RBW to achieve less than 0,1 dB error in signal power .18

– 4 – 61280-2-9 © IEC:2009
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 2-9: Digital systems –
Optical signal-to-noise ratio measurement
for dense wavelength-division multiplexed systems

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 61280-2-9 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics
This second addition cancels and replaces the first edition published in 2002 and constitutes
a technical revision. The main changes from the previous edition are as follows:
• A paragraph has been added to the Scope describing the limitations due to signal spectral
width and wavelength filtering.
• Annex B has been added to further explain error in measuring noise level due to signal
spectral width and wavelength filtering.

61280-2-9 © IEC:2009 – 5 –
The text of this standard is based on the following documents:
CDV Report on voting
86C/823/CDV 86C/864/RVC
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 procedures, can be found on the IEC website.
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.
– 6 – 61280-2-9 © IEC:2009
INTRODUCTION
At the optical interfaces within wavelength-division multiplexed (WDM) networks, it is
desirable to measure parameters that provide information about the integrity of the physical
plant. Such parameters are necessary to monitor network performance as an integral part of
network management. They are also necessary to assure proper system operation for
installation and maintenance of the network.
Ideally, such parameters would directly correspond to the bit error ratio (BER) of each
channel of a multichannel carrier at the particular optical interface. Related parameters such
as Q-factor or those calculated from optical eye patterns would provide similar information,
that is, they would correlate to the channel BER. However, it is difficult to obtain access to
these parameters at a multichannel interface point. It is necessary to demultiplex the
potentially large number of channels and make BER, Q-factor, or eye-diagram measurements
on a per-channel basis.
In contrast, useful information about the optical properties of the multichannel carrier is
readily obtained by measuring the optical spectrum. Wavelength-resolved signal and noise
levels provide information on signal level, signal wavelength, and amplified spontaneous
emission (ASE) for each channel. Spectral information, however, does not show signal
degradation due to wave-shape impairments resulting from polarization-mode dispersion
(PMD), and chromatic dispersion. Also, intersymbol interference and time jitter are not
revealed from an optical signal to noise ratio (OSNR) measurement. In spite of these
limitations, OSNR is listed as an interface parameter in ITU-T Rec. G.692 [1] , as an optical
monitoring parameter in ITU-T Rec. G.697 [2] and in ITU-T G Rec. Sup. 39 [3].
___________
Figures in brackets refer to the bibliography.

61280-2-9 © IEC:2009 – 7 –
FIBRE OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES –

Part 2-9: Digital systems –
Optical signal-to-noise ratio measurement
for dense wavelength-division multiplexed systems

1 Scope
This part of IEC 61280 provides a parameter definition and a test method for obtaining optical
signal-to-noise ratio (OSNR) using apparatus that measures the optical spectrum at a
multichannel interface. Because noise measurement is made on an optical spectrum analyzer,
the measured noise does not include source relative intensity noise (RIN) or receiver noise.
Three implementations for an optical spectrum analyser (OSA) are discussed: a diffraction-
grating-based OSA, a Michelson interferometer-based OSA, and a Fabry-Perot-based OSA.
Performance characteristics of the OSA that affect OSNR measurement accuracy are
provided.
A typical optical spectrum at a multichannel interface is shown in Figure 1. Important
characteristics are as follows.
• The channels are placed nominally on the grid defined by ITU Recommendation
G.694.1.[4]
• Individual channels may be non-existent because it is a network designed with optical
add/drop demultiplexers or because particular channels are out of service.
• Both channel power and noise power are a function of wavelength.
For calculating the OSNR, the most appropriate noise power value is that at the channel
wavelength. However, with a direct spectral measurement, the noise power at the channel
wavelength is included in the signal power and is difficult to extract. An estimate of the
channel noise power can be made by interpolating the noise power value between channels.
The accuracy of est
...