IEC TR 61292-2:2003

Optical amplifier technical reports - Part 2: Theoretical background for noise figure evaluation using the electrical spectrum analyzer

Applies to all commercially available optical amplifiers including optical fibre amplifiers using active fibres and semiconductor optical amplifiers using semiconductor gain media. The object is to provide the theoretical background to clause 6 (Calculation) of IEC 61290-3-2.

General Information

• Status: Published
• Publication Date: 19-Jan-2003
• ICS: 33.160.10 - Amplifiers
• ICS: 33.180.30 - Optic amplifiers
• Technical Committee: SC 86C - Fibre optic systems, sensing and active devices
• Drafting Committee: WG 3 - TC 86/SC 86C/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 31-Dec-2002
• Completion Date: 20-Jan-2003

Overview

IEC TR 61292-2:2003 is a technical report that provides the theoretical background for evaluating the noise figure of optical amplifiers using an Electrical Spectrum Analyzer (ESA). It applies to all commercially available optical amplifiers, including optical fibre amplifiers (OFAs) using active fibres and semiconductor optical amplifiers (SOAs). The document supports Clause 6 (Calculation) of IEC 61290-3-2 by explaining the measurement theory, calibration approach and the mathematical basis for extracting noise contributions when using an ESA.

Key topics and requirements

• Scope and objective: The report focuses on the theory behind noise figure/noise factor evaluation for optical amplifiers measured with an ESA, addressing both OFAs and SOAs.
• Calibration theory: Describes the calibration setup and procedures (source module, receiver module, input/output attenuators, ESA) and the use of two measurement states (full input and reduced input by factor k > 1) to separate noise components.
• Noise decomposition:
  • Shot noise (frequency-independent) from the photodetector.
  • Relative Intensity Noise (RIN) of the optical source (frequency-dependent).
  • ESA thermal noise subtracted from measured spectra.
• Calculation strategy:
  • Subtract shot noise and RIN contributions from measured ESA noise powers.
  • Add the theoretical shot-noise term for an ideal photodetector (quantum efficiency = 1) to obtain the amplifier contribution.
  • Use ratio-type measurements - absolute receiver transfer function calibration is not required.
• Photodetector responsivity and transfer functions: Guidance on relating ESA voltages to optical photocurrents and on estimating effective responsivity when exact values are not necessary.
• Symbols and terminology: Annex A lists abbreviations and symbols (e.g., B, RIN, G, N_shot, N_rin) used throughout the derivations.

Practical applications and users

• Who uses it:
  • Test engineers and metrologists characterizing noise figure of OFAs and SOAs.
  • R&D teams developing optical amplifiers and receiver front-ends.
  • Standards and compliance personnel implementing IEC 61290-3-2 test methods.
• Why it’s useful:
  • Provides rigorous theoretical underpinning for ESA-based noise-figure tests.
  • Helps separate source and detector noise from amplifier-added noise for accurate noise figure and noise factor reporting.
  • Supports reproducible lab measurements and comparison of amplifier performance across vendors.

Related standards

• IEC 61290-3 – Optical fibre amplifiers: Basic specification – Test methods for noise figure parameters
• IEC 61290-3-2 – Noise figure parameters: Electrical spectrum analyzer method (this TR supplies the theoretical background for Clause 6)
• IEC 61291-1 – Generic specification and definitions used for optical amplifier testing

Keywords: IEC TR 61292-2:2003, optical amplifier, noise figure, electrical spectrum analyzer, ESA, RIN, shot noise, photodetector, optical fibre amplifier, semiconductor optical amplifier, calibration, noise factor.

Standards Content (Sample)

TECHNICAL IEC
REPORT
TR 61292-2
First edition
2003-01
Optical amplifier technical reports –
Part 2:
Theoretical background for noise figure evaluation
using the electrical spectrum analyzer
Reference number
IEC/TR 61292-2:2003(E)
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,
edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
base publication incorporating amendment 1 and the base publication incorporating
amendments 1 and 2.
Further information on IEC publications
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology. Information relating to
this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is also available from the following:
• IEC Web Site (www.iec.ch)
• Catalogue of IEC publications
The on-line catalogue on the IEC web site (http://www.iec.ch/searchpub/cur_fut.htm)
enables you to search by a variety of criteria including text searches, technical
committees and date of publication. On-line information is also available on
recently issued publications, withdrawn and replaced publications, as well as
corrigenda.
• IEC Just Published
This summary of recently issued publications (http://www.iec.ch/online_news/
justpub/jp_entry.htm) is also available by email. Please contact the Customer
Service Centre (see below) for further information.
• Customer Service Centre
If you have any questions regarding this publication or need further assistance,
please contact the Customer Service Centre:
Email: [e-mail]
Tel: [phone]
Fax: [phone]
TECHNICAL IEC
REPORT
TR 61292-2
First edition
2003-01
Optical amplifier technical reports –
Part 2:
Theoretical background for noise figure evaluation
using the electrical spectrum analyzer
 IEC 2003  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
M
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – TR 61292-2  IEC:2003(E)
CONTENTS
FOREWORD . 3
INTRODUCTION .4
1 Scope and object . 5
2 Normative references. 5
3 Theoretical background of calibration . 5
3.1 Calculation for photocurrent measurement alternative . 7
3.2 Calculation of source RIN. 7
4 Theoretical background of noise factor calculation. 8
Annex A (informative) List of symbols and abbreviations .11
Figure 1 – Noise figure calibration setup . 5
Figure 2 – Equipment for electrical noise figure test . 8

TR 61292-2  IEC:2003(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL AMPLIFIER TECHNICAL REPORTS –
Part 2: Theoretical background for noise figure evaluation
using the electrical spectrum analyzer
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this technical report may be the subject of
patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example “state of the art”.
IEC 61292-2, which is a technical report, has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
86C/418/DTR 86C/474/RVC
Full information on the voting for the approval of this technical report 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.
The committee has decided that the contents of this publication will remain unchanged until 2008.
At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 4 – TR 61292-2  IEC:2003(E)
INTRODUCTION
This Technical Report should be read in conjunction with IEC 61290-3-2. To enhance the
clarity of this document, some of the text in document 61290-3-2 is repeated here. Definitions
of many terms and parameters contained in this Technical Report can be found in
IEC 61291-1.
Each abbreviation introduced in this Technical Report is generally explained in the text
the first time it appears. However, for an easier understanding of the whole text, a list
of the abbreviations used in this Technical Report is given in Annex A.

TR 61292-2  IEC:2003(E) – 5 –
OPTICAL AMPLIFIER TECHNICAL REPORTS –
Part 2: Theoretical background for noise figure evaluation
using the electrical spectrum analyzer
1 Scope and object
This Technical Report applies to all commercially available optical amplifiers (Oas) including
optical fibre amplifiers (OFAs) using active fibres and semiconductor optical amplifiers (SOAs)
using semiconductor gain media.
The object of this Technical Report is to provide the theoretical background to Clause 6
(Calculation) of IEC 61290-3-2.
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 61290-3: Optical fibre amplifiers – Basic specification – Test methods for noise figure
parameters
IEC 61290-3-2: Optical fibre amplifier test methods – Part 3-2: Noise figure parameters –
Electrical spectrum analyzer method
IEC 61291-1: Optical fibre amplifiers – Part 1: Generic specification
3 Theoretical background of calibration
The calibration setup is shown in Figure 1.
Receiver module
Source module
Variable output El. spectrum
Variable input Detector
attenuator analyser
attenuator
ESA
dB dB
Optical
DFB laser Polarisation
Electrical
filter
with isolator controller
amplifier
(optional)
Possibly separable
Modulation
source
Optical
Power meter
power meter
jumper cable
IEC  2970/02
Figure 1 – Noise figure calibration setup

– 6 – TR 61292-2  IEC:2003(E)
The following quantities are obtained during the calibration process; notice that all noise
measurement results are to be understood as ESA power levels after subtraction of the
thermal noise level:
P is optical input power at 0 dB setting of input attenuator.
in,0
S is electrical power of the modulation signal at 0 dB setting of
...