IEC 61291-1:2012

IEC 61291-1


®


Edition 3.0 2012-04



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE


Optical amplifiers –
Part 1: Generic Specification

Amplificateurs optiques –
Partie 1: Spécification générique


IEC 61291-1:2012

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IEC 61291-1



®


Edition 3.0 2012-04







INTERNATIONAL





STANDARD







NORME



INTERNATIONALE











Optical amplifiers –

Part 1: Generic Specification




Amplificateurs optiques –

Partie 1: Spécification générique

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

V
CODE PRIX


ICS 33.180.20 ISBN 978-2-8322-0074-2



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 61291-1 © IEC:2012


CONTENTS



FOREWORD . 3

1 Scope and object . 5

2 Normative references . 5


3 Terms, definitions and abbreviations . 6

3.1 Overview . 6

3.2 Terms and definitions . 8

3.2.1 OA devices and distributed amplifiers . 8

3.2.2 OA-assemblies . 20
3.3 Abbreviated terms . 23
4 Classification . 24
5 Requirements . 25
5.1 Preferred values . 25
5.2 Sampling . 25
5.3 Product identification for storage and shipping . 25
5.3.1 Marking . 25
5.3.2 Labelling. 25
5.3.3 Packaging . 25
6 Quality assessment . 25
7 Electromagnetic compatibility (EMC) requirements . 25
8 Test methods . 26
Bibliography . 27
Index of definitions . 28

Figure 1 – OA device and assemblies . 7
Figure 2 – Optical amplifier in a multichannel application . 8

Table 1 – Grouping of parameters and corresponding test methods or references . 26

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61291-1 © IEC:2012 – 3 –


INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



OPTICAL AMPLIFIERS –



Part 1: Generic Specification





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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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
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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 61291-1 has been prepared by subcommittee 86C: Fibre optic

systems and active devices, of IEC technical committee 86: Fibre optics.
This third edition cancels and replaces the second edition published in 2006. It is a technical
revision that includes the following significant changes: the definitions related to transient
behaviour have been extensively updated with terms from the 61290-4 series and the
definition for gain ripple has been added.
The text of this standard is based on the following documents:
CDV Report on voting
86C/1013/CDV 86C/1041/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.

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– 4 – 61291-1 © IEC:2012


This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.


A list of all the parts in the IEC 61291 series, published under the general title Optical

amplifiers, can be found on the IEC website.


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.

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61291-1 © IEC:2012 – 5 –


OPTICAL AMPLIFIERS –



Part 1: Generic Specification








1 Scope and object


This part of IEC 61291 applies to all commercially available optical amplifiers (OAs) and

optically amplified assemblies. It applies to OAs using optically pumped fibres (OFAs based
either on rare-earth doped fibres or on the Raman effect), semiconductors (SOAs), and
waveguides (POWAs). The object of this standard is:
– to establish uniform requirements for transmission, operation, reliability and environmental
properties of OAs;
– to provide assistance to the purchaser in the selection of consistently high-quality OA
products for his particular applications.
Parameters specified for OAs are those characterizing the transmission, operation, reliability
and environmental properties of the OA seen as a “black box” from a general point of view. In
the sectional and detail specifications a subset of these parameters will be specified
according to the type and application of the particular OA device or assembly.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61290 (all parts), Optical amplifiers –Test methods
IEC 61290-1-1, Optical amplifiers – Test methods – Part 1-1: Power and gain parameters –
Optical spectrum analyzer method
IEC 61290-1-2, Optical amplifiers – Test methods – Part 1-2: Power and gain parameters –
Electrical spectrum analyzer method
IEC 61290-1-3, Optical amplifiers – Test methods – Part 1-3: Power and gain parameters –

Optical power meter method
IEC 61290-3-1, Optical amplifiers – Test methods – Part 3-1: Noise figure parameters –
Optical spectrum analyzer method
IEC 61290-3-2, Optical amplifiers – Test methods – Part 3-2: Noise figure parameters –
Electrical spectrum analyzer method
IEC 61290-4-1, Optical amplifiers – Test methods – Part 4-1: Gain transient parameters –
Two wavelength method
IEC 61290-4-2, Optical amplifiers – Test methods – Part 4-2: Gain transient parameters –
Broadband source method
IEC 61290-5-1, Optical amplifiers – Test methods – Part 5-1: Reflectance parameters –
Optical spectrum analyzer method

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– 6 – 61291-1 © IEC:2012


IEC 61290-5-2, Optical amplifiers – Test methods – Part 5-2: Reflectance parameters –

Electrical spectrum analyzer method


IEC 61290-5-3, Optical fibre amplifiers – Basic specification– Part 5-3: Test methods for

reflectance parameters – Reflectance tolerance using an electrical spectrum analyzer


IEC 61290-6-1, Optical fibre amplifiers – Basic specification – Part 6-1: Test methods for

pump leakage parameters – Optical demultiplexer


IEC 61290-7-1, Optical amplifiers – Test methods – Part 7-1: Out-of-band insertion losses –

Filtered optical power meter method

IEC 61290-10-1, Optical amplifiers – Test methods – Part 10-1: Multichannel parameters –
Pulse method using an optical switch and optical spectrum analyzer
IEC 61290-10-2, Optical amplifiers – Test methods – Part 10-2: Multichannel parameters –
Pulse method using a gated optical spectrum analyzer
IEC 61290-10-3, Optical amplifiers – Test methods – Part 10-3: Multichannel parameters –
Probe methods
IEC 61290-10-4, Optical amplifiers – Test methods – Part 10-4: Multichannel parameters –
Interpolated source subtraction method using an optical spectrum analyzer
IEC 61290-11-1, Optical amplifiers – Test methods – Part 11-1: Polarization mode dispersion
parameter – Jones matrix eigenanalysis (JME)
IEC 61290-11-2, Optical amplifiers – Test methods – Part 11-2: Polarization mode dispersion
parameter – Poincaré sphere analysis method
IEC 61291-2, Optical amplifiers – Part 2: Digital applications – Performance specification
template
IEC 61291-4, Optical amplifiers – Part 4: Multichannel applications – Performance speci-
fication template
IEC 61291-5-2, Optical amplifiers – Part 5-2: Qualification specifications – Reliability
qualification for optical fibre amplifiers
IEC/TR 61292-3, Optical amplifiers – Part 3: Classification, characteristics and applications

IEC Guide 107, Electromagnetic compatibility – Guide to the drafting of electromagnetic
compatibility publications
3 Terms, definitions and abbreviations
3.1 Overview
The definitions listed in this clause refer to the meaning of the terms used in the specifications
of OAs. Only those parameters listed in the appropriate specification template, as in
IEC 61291-2 and IEC 61291-4, are intended to be specified.
NOTE 1 The numbered terms in this clause are indexed and cross-referenced in Annex A.
The list of parameter definitions of OAs, given in this clause, is divided into two parts: the first
part, in 3.1.2, lists those parameters relevant for OA devices, namely power, pre-, line- and

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61291-1 © IEC:2012 – 7 –


distributed amplifiers; the second part, in 3.2, lists the parameters relevant for optically

amplified, elementary assemblies, namely the optically amplified transmitter (OAT) and the

optically amplified receiver (OAR).


In any case where the value of a parameter is given for a particular device, it will be

necessary to specify certain appropriate operating conditions such as temperature, bias

current, pump optical power, etc. In this clause, two different operating conditions are referred

to: nominal operating conditions, which are those suggested by the manufacturer for normal

use of the OA, and limit operating conditions, in which all the parameters adjustable by the

user (e.g. temperature, gain, pump laser injection current, etc.) are at their maximum values,
according to the absolute maximum ratings stated by the manufacturer.


The OA shall be considered as a “black box”, as shown in Figure 1. The OA device shall have
two optical ports, namely an input and an output port (Figure 1a)). The OAT and OAR are to
be considered as an OA integrated on the transmitter side or on the receiver side,
respectively. Both kinds of integration imply that the connection between the transmitter or the
receiver and the OA is proprietary and not to be specified. Consequently, only the optical
output port can be defined for the OAT (after the OA, as shown in Figure 1b) and only the
optical input port can be defined for the OAR (before the OA, as shown in Figure 1c)). The
optical ports may consist of unterminated fibres or optical connectors. Electrical connections
for power supply (not shown in Figure 1) are also necessary. Following this "black box"
approach, the typical loss of one connection and the corresponding uncertainty will be
included within the values of gain, noise figure and other parameters of the OA device.
NOTE 2 For distributed amplifiers, as described in Clause 4, this black-box configuration may be simulated for
test purposes, for example by attaching a reference fibre to test a Raman pump unit.

Input Output Output Input
Tx
OA OA
Rx
OA
port port port port
IEC  1483/06

Figure 1a – OA device Figure 1b – OAT Figure 1c – OAR
Figure 1 – OA device and assemblies
The OA amplifies signals in a nominal operating wavelength region. In addition, other signals
outside of the band of operating wavelength can in some applications, also cross the OA. The
purpose of these out-of-band signals and their wavelength, or wavelength region, can be
specified in the detail specifications.
When signals at multiple wavelengths are incident on the OA, as is the case in multichannel

systems, suitable adjustment of the definitions of some existing relevant parameters is
needed together with the introduction of definitions of new parameters relevant to this
different application.
A typical configuration of an OA in a multichannel application is shown in Figure 2. At the
transmitting side m signals, coming from m optical transmitters, Tx , Tx , . . . Tx , each with a
1 2 m
unique wavelength, λ , λ , . . . λ , respectively, are combined by an optical multiplexer (OM).
1 2 m
At the receiving side the m signals at λ , λ , . . . λ , are separated with an optical
1 2 m
demultiplexer (OD) and routed to separate optical receivers, Rx , Rx , . . . Rx , respectively.
1 2 m
To characterize the OA in this multichannel application, an input reference plane and an
output reference plane are defined at the OA input and output ports, respectively, as shown in
Figure 2.

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– 8 – 61291-1 © IEC:2012



   Input Output

Tx Rx
1 1
reference
reference

plane plane



Tx Rx
2 2


OM OD
OA


P OA P
i1 o1

P P

i2 o2

. . . . . .
Tx Rx
m m
P P
im om
P (λ)
ASE
IEC  1484/06

Figure 2 – Optical amplifier in a multichannel application
At the input reference plane, m input signals at the m wavelengths are considered, each with a
unique power level, P , P , . . . P , respectively. At the output reference plane, m output
i1 i2 im
signals at the m wavelengths, resulting from the optical amplification of the corresponding m
input signals, are considered, each with power level P , P , . . . P , respectively. Moreover,
o1 o2 om
the amplified spontaneous emission, ASE, with a noise power spectral density, P (λ), is
ASE
also to be considered at the OA output port.
Most definitions of relevant single-channel parameters can be suitably extended to
multichannel applications. When this extension is straightforward, the word “channel” will be
added to the pertinent parameter. In particular, the noise figure and the signal-spontaneous
noise figure may be extended to multichannel applications, channel by channel, by
considering the value of P (λ) at each channel wavelength and the channel signal
ASE
bandwidth. For each channel wavelength there will be a unique value of noise figure that will
be a function of the input power level of all signals. In this case the parameters, channel noise
figure and channel signal-spontaneous noise figure, are introduced. However some additional
parameters also need to be defined. For each parameter, the particular multichannel
configuration, including the full set of channel signal wavelengths and input powers, needs to
be specified.
NOTE 3 Except where noted, the optical powers mentioned in the following are intended as average powers.
NOTE 4 The parameters defined below will in general depend also on temperature and polarization state of input
channels. The temperature and state of polarization should be kept constant or controlled or be measured and
reported together with the measured parameter.

NOTE 5 It should be noted that the measured optical powers are open beam powers: this can result in differences
of about 0,18 dB in the measurement of absolute power levels.
NOTE 6 In the case of the distributed amplifier, all the parameters are related to a suitable reference fibre used to
emulate the transmission fibre in conjunction with the pumping assembly.
3.2 Terms and definitions
3.2.1 OA devices and distributed amplifiers
For the purposes of this document, the following terms and definitions apply.
NOTE These terms and conditions furthermore apply, in general, to optical amplifiers under the IEC 61290 and
IEC 61291 series.

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61291-1 © IEC:2012 – 9 –


3.2.1.1

gain

in an OA which is externally connected to an input jumper fibre, the increase of signal optical

power from the output end of the jumper fibre to the OA output port, expressed in dB


Note 1 to entry: The gain includes the connection loss between the input jumper fibre and the OA input port.

Note 2 to entry: It is assumed that the jumper fibres are of the same type as the fibres used as input and output

port of the OA.


Note 3 to entry: Care should be taken to exclude the amplified spontaneous emission power from the signal
optical powers.


3.2.1.2
small-signal gain
gain of the amplifier, when operated in linear regime, where it is essentially independent of
the input signal optical power, at a given signal wavelength and pump optical power level
Note 1 to entry: This property can be described at a discrete wavelength or as a function of wavelength.
3.2.1.3
reverse gain
gain measured using the input port of the OA as output port and vice versa
3.2.1.4
reverse small-signal gain
small-signal gain measured using the input port of the OA as output port and vice versa
3.2.1.5
maximum gain
highest gain that can be achieved when the OA is operated within the stated nominal
operating conditions
3.2.1.6
maximum small-signal gain
highest small-signal gain that can be achieved when the OA is operated within the stated
nominal operating conditions
3.2.1.7
maximum gain wavelength
wavelength at which the maximum gain occurs
3.2.1.8
maximum small-signal gain wavelength

wavelength at which the maximum small-signal gain occurs
3.2.1.9
wavelength variation
peak-to-peak variation of the gain over a given wavelength range
3.2.1.10
small-signal gain wavelength variation
peak-to-peak variation of the small-signal gain over a given wavelength range
3.2.1.11
gain-slope under single wavelength operation (for analogue operation)
in the presence of a signal of given wavelength and input power, the derivative of the gain of
a small probe versus wavelength, at the signal wavelength

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– 10 – 61291-1 © IEC:2012


Note 1 to entry: The probe total average power level must be at least 20 dB below the input signal level, to

minimize the effect on the gain wavelength-profile.

3.2.1.12

polarization-dependent gain

PDG

the maximum variation of the OA gain due to a variation of the state of polarization of the

input signal, at nominal operating conditions


Note 1 to entry: A source of PDG in OAs is the polarization dependent loss of the passive components used

inside.

3.2.1.13

channel gain (for multichannel operation)
gain for each channel (at wavelength λ ) in a specified multichannel configuration
j
Channel gain can be expressed as follows (P and P being respectively the input and output
ij oj
power levels, in dBm, of the j-th channel and j = 1, 2, . . . n; n total number of channels):
G = P – P


j oj ij
Note 1 to entry: Channel gain is expressed in dB.
Note 2 to entry: Since the amplifier saturation power level is determined by the combined effect of the input
signals at all wavelengths, the channel gain is dependent on the input power level of all signals.
3.2.1.14
multichannel gain variation (interchannel gain difference) (for multichannel operation)
difference between the channel gains of any two of the channels in a specified multichannel
configuration
Multichannel gain variation can be expressed as follows (G and G being respectively the
j l
channel gains of j-th and l-th channel and j, l = 1, 2, . . . n; j ≠ l; n total number of channels):
ΔG = G – G
jl j l
Note 1 to entry: Multichannel gain variation is expressed in dB.
Note 2 to entry: Normally this parameter is specified as the maximum multichannel gain variation, intended as the
maximum absolute value of multichannel gain variation, considering all possible combinations of channel pairs. The
input power levels would normally be set to their minimum and maximum specified values. Input power levels may
also be specified to achieve certain gain values or total output power levels. Maximum multichannel gain variation
can be expressed as follows:
ΔG = MAX {|ΔGjl|}
MAX j,l
Note 3 to entry: Maximum multichannel gain variation is expressed in dB.

Note 4 to entry: This parameter is often referred to as gain flatness.
3.2.1.15
gain cross-saturation (for multichannel operation)
ratio of the change in channel gain of one channel, ΔG , to a given change in the input power
j
level of another channel, ΔP , while the input power levels of all other channels are ke
...