IEC 61290-1-2:2026

IEC 61290-1-2 ®
Edition 3.0 2026-02
INTERNATIONAL
STANDARD
REDLINE VERSION
Optical amplifiers - Test methods -
Part 1-2: Power and gain parameters - Electrical spectrum analyzer method
ICS 33.180.30 ISBN 978-2-8327-1054-8
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CONTENTS
FOREWORD . 2
INTRODUCTION .
1 Scope . 4
2 Normative references . 5
3 Terms, definitions, abbreviated terms, and symbol . 5
3.1 Terms and definitions. 5
3.2 Abbreviated terms . 5
3.3 Symbols . 5
4 Apparatus . 5
5 Test sample . 8
6 Procedures . 9
7 Calculation . 12
8 Test results . 13
Bibliography . 16

Figure 1 – Typical arrangement of the electrical spectrum analyzer test apparatus for
measurement of average optical input signal power, electrical input signal power, and
electrical output signal power . 6
Figure 2 – Typical behaviour variation of gain as a function of input signal power . 7

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Optical amplifiers - Test methods -
Part 1-2: power and gain parameters -
Electrical spectrum analyzer method

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
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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
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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
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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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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes made
to the previous edition IEC 61290-1-2:2005. A vertical bar appears in the margin wherever a
change has been made. Additions are in green text, deletions are in strikethrough red text.

IEC 61290-1-2 has been prepared by subcommittee 86C: Fibre optic systems, sensing and
active devices, of IEC technical committee 86: Fibre optics. It is an International Standard.
This third edition cancels and replaces the second edition published in 2005. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of information on the applicability of this document to the scope;
b) harmonization of the scope with the IEC 61290-1 series;
c) addition of safety recommendations to Clause 4 and Clause 5;
d) correction of an error in Clause 7, item e);
e) replacement of the term "wavelength measurement accuracy" with "wavelength accuracy".
The text of this International Standard is based on the following documents:
Draft Report on voting
86C/1973/CDV 86C/1991/RVC
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 61290 series, published under the general title Optical amplifiers -
Test methods, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION
This International Standard is devoted to the subject of optical amplifiers. The technology of
optical amplifiers is still rapidly evolving, hence amendments and new editions to this standard
can be expected.
Each abbreviation introduced in this International Standard is explained in the text at least the
first time it appears. However, for an easier understanding of the whole text, a list of all
abbreviations used in this International Standard is given in Clause 3.
1 Scope
This part of IEC 61290 applies to all commercially available optical amplifiers (OAs) and
optically amplified sub-systems. It applies to OAs using optically pumped fibres (OFAs based
on either rare-earth doped fibres or on the Raman effect), semiconductors (SOAs), and planar
optical waveguides (POWAs). This document does not apply to polarization-maintaining optical
amplifiers.
NOTE The applicability of the test methods described in the present standard to distributed Raman amplifiers is for
further study.
This document defines uniform requirements for accurate and reliable measurements, by means
of the electrical spectrum analyzer test method, of the following OA parameters, as defined in
IEC 61291-1, Clause 3:
a) nominal output signal power;
b) gain;
c) reverse gain;
d) maximum gain;
e) polarization-dependent gain.
f) large-signal output stability;
g) saturation output power;
h) maximum input signal power;
i) maximum output signal power;
j) input power range;
k) output power range;
l) maximum total output power.
In addition, this test method provides a means for measuring the following parameters:
– maximum gain wavelength;
– gain wavelength band.
NOTE All numerical values followed by (‡) are suggested values for which the measurement is assured. Other
values may be acceptable, but should be verified.
This document specifically covers single-channel amplifiers. For multichannel amplifiers, the
IEC 61290-10 series applies.
NOTE 1 The applicability of the test methods described in this document to distributed Raman amplifiers is for
further study.
NOTE 2 A test method for polarization-maintaining optical amplifiers is for further study.

See Bibliography.
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 60793-1-40, Optical fibres - Part 1-40: Measurement methods and test procedures -
Attenuation
IEC 61291-1:2005, Optical amplifiers - Part 1: Generic specification
3 Terms, definitions, abbreviated terms, and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61291-1 apply.
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
3.2 Abbreviated terms
ASE amplified spontaneous emission
DBR distributed Bragg reflector (laser diode)
DFB distributed feedback (laser diode)
ECL external cavity laser (diode)
LED light emitting diode
OA optical amplifier
OFA optical fibre amplifier
POWA planar optical waveguide amplifier
SOA semiconductor optical amplifier
3.3 Symbols
(‡) indicates a suggested value for which a measurement is assured.
4 Apparatus
A diagram of the measurement set-up is given in Figure 1.

A first edition of IEC 61291-1 was published in 1998 under the title Optical fibre amplifiers – Part 1: Generic
specification.
a) Average optical input signal power

b) Electrical input signal power

c) Electrical output signal power

Key
J1, J2 Optical connectors
Figure 1 – Typical arrangement of the electrical spectrum analyzer test apparatus for
measurement of average optical input signal power, electrical input signal power, and
electrical output signal power
The test equipment items with their required characteristics listed in a) to k) in this clause, is
needed shall be used.
a) Optical source: the optical source shall be either at a fixed wavelength or wavelength
tuneable.
1) Fixed-wavelength optical source: the optical source shall generate light with a
wavelength and optical power specified in the relevant detail specification. The optical
source shall emit modulated light with the full width at half maximum of the spectrum
narrower than 1 nm (‡), unless otherwise specified in the relevant detail specification. A
distributed feedback (DFB) laser, a distributed Bragg reflector (DBR) laser, an external
cavity laser (ECL) diode and, or a light-emitting diode (LED) with a narrow-band filter
are applicable can be used as the optical source, for example. The suppression ratio for
of the side modes for the DFB laser, the DBR laser or, and the ECL shall be higher than
30 dB (‡). The output power fluctuation shall be less than 0,05 dB (‡), which may be
better attainable with can require the insertion of an optical isolator at the output port of
the optical source. Spectral broadening at the foot of the lasing spectrum shall should
be minimal for laser sources.
2) Wavelength-tuneable optical source: this optical source shall be able to generate
wavelength-tuneable light within the wavelength range specified in the relevant detail
specification. Its optical power shall be specified in the relevant detail specification. The
optical source shall emit modulated light with the full width at half maximum of the
spectrum narrower than 1 nm (‡), unless otherwise specified in the relevant detail
specification. An ECL or a LED with a narrow bandpass optical filter is applicable can
be used as the optical source, for example. The suppression ratio of side modes for the
ECL shall be higher than 30 dB (‡). The output power fluctuation shall be less than
0,05 dB, which may be better attainable with can require the insertion of an optical
isolator at the output port of the optical source. Spectral broadening at the foot of the
lasing spectrum shall should be minimal for the ECL.
NOTE The use of a LED should be limited to small-signal gain measurements.
NOTE 1 The regime of small-signal gain is the range of input signal power sufficiently small so that the OA
under test operates in the linear region. This regime can be found by plotting the signal gain G versus the
averaged input optical signal power [see Formula (3)]. The linear region is the range of input optical signal
powers where the gain is nearly independent of input optical signal power (see Figure 2). An averaged input
optical signal power between −30 dBm and −40 dBm is generally well within this range. In the saturated
region, the signal power is large enough to well suppress the ASE.

Figure 2 – Typical behaviour variation of gain as a function of input signal power
b) Optical power meter: it shall have a measurement accuracy better uncertainty less than
±0,2 dB, irrespective of the state of polarization, within the operational wavelength
bandwidth of the OA. The optical power meter shall have a dynamic range that exceeds the
measured gain is required (e.g. 40 dB).
c) Electrical spectrum analyzer: the spectral-power-measurement error shall be better than
within ±0,5 dB (optical). The linearity shall be better than within ±0,2 dB (optical).
d) Optical isolator: optical isolators may be used to bracket at the input and output ports of the
OA. The polarization-dependent loss variation of the isolator shall be better less than 0,2 dB
(‡). Optical isolation shall be better higher than 40 dB (‡). The reflectance from this device
shall be smaller less than −40 dB (‡) at each port.
e) Variable optical attenuator: the attenuation range and stability shall be over 40 dB (‡) and
better than within ±0,1 dB (‡), respectively. The reflectance from this device shall be smaller
less than –40 dB (‡) at each port.
f) Polarization controller: this device shall be able to provide as input signal light all possible
states of polarization (e.g. linear, elliptical and circular). For example, the polarization
controller may can consist of a linear polarizer followed by an all-fibre-type polarization
controller, or of a linear polarizer followed by a quarter-wave plate rotatable by minimum of
90° and a half-wave plate rotatable by minimum of 180°. The loss variation of the
polarization controller shall be less than 0,2 dB (‡). The reflectance from this device shall
be smaller less than −40 dB (‡) at each port. The use of a polarization controller is
considered optional, except for the measurement of polarization-dependent gain, but may
also can be necessary to achieve the desired accuracy of other power and gain parameters
for OA devices exhibiting significant polarization-dependent gain.
g) Optical fibre jumpers: the mode field diameter of the optical fibre jumpers used should be
as close as possible to that of fibres used as input and output ports of the OA. The
reflectance from this device shall be smaller less than −40 dB (‡) at each port, and the
length of the jumper shall be shorter than 2 m.
h) Optical connectors (J1 and J2 in Figure 1): the connection loss repeatability shall be better
than within ±0,2 dB.
i) Optical detector: this device shall be highly polarization insensitive and have a linearity
better than within ±0,2 dB. To minimize the saturation effects due to high DC levels, the
optical detector output shall be AC coupled. The maximum safe input power of the optical
detector should be sufficiently large to ensure safe testing of the OA.
NOTE In order to minimize the saturation effects due to high d.c. levels, the optical detector output shall be
a.c. coupled.
NOTE 2 The maximum safe input power to the optical detector can be effectively increased by adding an optical
attenuator with very low polarization sensitivity in front of the optical detector and using it as an integral part of
the optical detector.
j) Signal generator: the signal generator shall generate a sinusoidal wave at a frequency
higher than several hundreds of kilohertz with a linearity better than within ±1,5 dB.
NOTE 3 For small-signal gain measurements an optical chopping system could can be used alternatively.
k) Optical coupler: the polarization dependence of the branching ratio of the coupler shall
should be minimal. Change of the state of polarization of the input light shall should be
negligible. Any free port of the coupler shall be properly terminated in such a way as to
decrease the reflectance below to less than −40 dB (‡).
5 Test sample
The sample type and test parameters shall be confirmed prior to the test.
The OA shall operate at nominal operating conditions. If the OA is likely to cause laser
oscillations due to unwanted reflections, optical isolators should be used to bracket at the input
and output ports of the OA under test. This will minimize the signal instability and the
measurement inaccuracy uncertainty.
For measurements of parameters a) to l) d) of Clause 1 except e), care shall be taken in
maintaining, the state of polarization of the input light shall be maintained during the
measurement. Changes in the polarization state of the input light may can result in input optical
power changes because of the slight polarization dependency expected from all the optical
components used, this leading to measurement errors slight polarization dependence of the
optical components used in the amplifier. This polarization dependence can lead to
measurement errors.
For safety reasons, the optical signal power should be reduced by adjusting the optical source
or variable optical attenuator each time a connector is inserted or removed during the
measurement. Other protective measures are described in IEC 60825-1 and IEC 60825-2.
6 Procedures
The related measurement procedure is as follows a) to h).
a) Nominal output signal power: the nominal output signal power is the minimum output signal
optical power that is obtained at the input signal optical power specified in the relevant detail
specification under the nominal operating conditions specified in the relevant detail
specification.
To find this minimum value, input and output signal power levels shall be continuously
monitored for a given duration of time, and in presence of changes in the state of polarization
and other instabilities, as specified in the relevant detail specification. The measurement
procedures described below in steps 1) to 10) shall be followed, with reference to Figure 1.
1) Set the optical source at the test wavelength specified in the relevant detail specification.
2) Measure the branching ratio of the optical coupler through the signal power levels exiting
the two output ports, with an optical power meter.
3) Measure the loss, L , of the optical fibre jumper between the OA and the optical detector
j
[see Figure 1c)] by the insertion loss technique described in IEC 60793-1-40, Method B.
4) Set the signal generator in a way that the light emitted by the optical source is intensity
modulated at the frequency specified in the detail specification. The modulation
frequency shall be higher than several hundreds of kilohertz (e.g. 1 MHz) to avoid
waveform distortion due to slow gain response, unless otherwise specified. The
modulation depth shall be unchanged during the measurement.
5) For measuring optical powers with the electrical spectrum analyzer, the following
calibration procedure (of the electrical spectrum analyzer) is needed, the electrical
spectrum analyzer shall be calibrated as follows using an optical power meter:
i) for calibration, set the time-averaged optical power P using an optical power meter
cal
[see Figure 1a)], as specified in the relevant detail specification;
ii) measure the AC component of the input signal electrical power P with the optical
e,cal
detector and the electrical spectrum analyzer.
Keep the modulation depth unchanged during the measurement. The time-averaged
optical signal power P shall be derived from the AC component of the corresponding
signal electrical power P (measured with the electrical spectrum analyzer) using
e
Formula (1).
P= P PP
(1)
cal e e,cal
6) Set the optical source and the variable optical attenuator in such a way as to provide,
at the input port of the OA, the time-averaged input optical signal power specified P
in
in the relevant detail specification. Record the time-averaged optical power P
o
measured with an optical power meter at the other (second) output port of the optical
coupler, as shown in Figure 1a).
7) Keep the time-averaged optical signal power P at the OA input constant during the
in
following measurements, by monitoring the second output port of the coupler and, if
necessary, setting the variable optical attenuator in such a way that the time-averaged
optical power P exiting the second output port of the optical coupler remains constant.
o
8) Set the polarization controller at a given state of polarization as specified in the
relevant detail specification, and monitor, by means of the electrical spectrum
analyzer, the (time-averaged) optical signal power at the output of the OA for the
specified period of time, recording the minimum value.
9) Change the state of polarization of the input signal by means of the polarization
controller, trying to minimize the output optical signal power measure with the electrical
spectrum analyzer, and repeat step 8).
10) Repeat step 9) for the different states of polarization indicated in the relevant detail
specification, and finally take the absolute minimum output optical signal power
recorded in the various conditions: P .
out-min
NOTE 1 Optical connectors J1 and J2 should not be removed during the measurement
to avoid additional measurement errors uncertainty due to reconnection.
NOTE 2 The polarization controller should be operated as specified in the relevant
detail specifications. A possible way, when using a linear polarizer followed by a
quarter-wave rotatable plate, is the following When using a linear polarizer followed by
a rotatable quarter-wave plate and a rotatable half-wave plate, the polarization
controller can be operated as follows:
i) the linear polarizer is adjusted so that the OA output power is maximized;
ii) the quarter-wave plate is then rotated by at least 90° in small steps;
iii) at each step of the quarter-wave plate, the half-wave plate is rotated by at least
180° in small steps.
b) Gain: as in a), but this method permits determination of the gain, by measuring the
modulated electrical power, S and S , corresponding to the OA input and output signal
in out
powers, respectively, at the signal wavelength. The method, using a modulated input signal
and an electrical spectrum analyzer, permits discrimination of the output signal from the
amplified spontaneous emission (ASE) because the ASE is free of modulation at the
specified frequency. Thus, after filtering out the DC power component, the electrical output
power at the modulation frequency is considered free of the ASE. The measurement
procedures described below in steps 1) to 5) shall be followed.
1) Set the signal generator in such a way that the light emitted by the optical source is
intensity modulated at the frequency specified in the detail specification. The modulation
frequency shall be higher than several hundreds of kilohertz (e.g. 1 MHz) to avoid
waveform distortion due to slow gain response, unless otherwise specified.
2) Set the optical source to the test wavelength specified in the relevant detail specification.
3) Measure the time-averaged input optical signal power with the optical power meter, as
shown in Figure 1a), for calibration reference. Set the optical source and the variable
optical attenuator in a way to provide, at the input port of the OA, the time-averaged
input optical signal power specified in the relevant detail specification.
4) Measure the electrical power, S , corresponding to the specified time-averaged input
in
optical signal power at the modulation frequency by means of the optical detector and
the electrical spectrum analyzer, as shown in Figure 1b).
5) Measure the electrical power, S , corresponding to the OA output optical signal at the
out
modulation frequency by means of the optical detector and the electrical spectrum
analyzer, as shown in Figure 1c).
NOTE Optical connectors J1 and J2 should not be removed during the measurement to avoid measurement

error due to reconnection.
c) Reverse gain: as in b), but with the OA operating with the input port used as output port and
vice-versa.
d) Maximum gain: as in b), but using a wavelength-tuneable optical source. Repeat steps 1) to
5) at different wavelengths to cover the wavelength range specified in the relevant detail
specification, and replace step 2) with the following step 2):
2) Set the wavelength-tuneable optical source at a test wavelength within the specified
wavelength range.
NOTE 1 The wavelength should be changed by steps smaller than 1 nm (‡) around the
wavelength where the ASE spectral profile, observed (e.g. with an optical spectrum analyzer
or a monochromator) without the input signal, takes its maximum value, unless otherwise
specified.
NOTE 2 A wavelength measurement accuracy of ±0,01 nm, around 1 550 nm, is attainable can be attained with
commercially available wavelength meters based on interference-fringes counting techniques. Some tuneable
external-cavity laser-diode instruments provide a wavelength measurement accuracy of ±0,2 nm or better.
e) Maximum gain wavelength: as in d).
f) Maximum gain variation with temperature: Under consideration.
f) Gain wavelength band: as in d).
g) Gain variation: as in d).
i) Gain stability: Under consideration.
h) Polarization-dependent gain: as in b), but using a polarization controller between the
variable optical attenuator and the connector J1 (see Figure 1); repeat steps 1) to 5) at
different states of polarization as specified in the relevant detail specification, and replace
step 2) with the following step 2):
2) Set the optical source to the test wavelength specified in the relevant detail specification.
Set the polarization controller at a given state of polarization as specified in the relevant
detail specification.
NOTE 1 The state of polarization of the input signal should be changed after each
measurement of S and S by means of the polarization controller, so that substantially
in out
all the states of polarization, in principle, are successively launched into the input port
of the OA under test.
NOTE 2 The polarization controller should be operated as specified in the relevant detail
specifications. A possible way, When using a linear polarizer followed by a quarter-wave
rotatable plate, is the following When using a linear polarizer followed by a rotatable
quarter-wave plate and a rotatable half-wave plate, the polarization controller can be
operated as follows:
i) the linear polarizer should be is adjusted so that the OA output power is maximized;
ii) the quarter-wave plate is then rotated by at least 90° in small steps;
iii) at each step of the quarter-wave plate, the half-wave plate is rotated by at least 180°
in small steps.
Another possible way is Alternatively, the polarization controller can be operated to select
four known and specified states of polarization to allow matrix calculation of the resulting
polarization-dependent gain.
NOTE 3 A short optical jumper at the OA input, kept as straight or and stable as possible,
should be used, in order to minimize the change of the state of polarization induced in it the
jumper by possible stress and anisotropy.
NOTE 4 The polarization-dependent loss of the optical connector should be less than 0,2 dB
(‡).
k) Large-signal output stability: under consideration.
l) Saturation output power: under consideration.
m) Maximum input signal power: under consideration.
n) Maximum output signal power: under consideration.
o) Input power range: under consideration.
p) Output power range: under consideration.
q) Maximum total output power: under consideration.
7 Calculation
Calculation is carried out as follows described below in steps a) to h).
a) Nominal output signal power: the nominal output signal power P (in dBm) shall be calculated
using Formula (2).
P = 10 log (P ) + L (dBm)
out-min j
P 10 log PL+
( )
(2)
10 out-min j
where
P is the recorded absolute minimum value of output optical signal power (in mW);
out-min
L is the insertion of the optical fibre jumper placed between the OA and the optical
j
detector (in dB).
NOTE 1 The measurement error uncertainty can be better than ±0,5 dB (‡), depending mainly on the accuracy
of the electrical spectrum analyzer accuracy.
b) Gain:
The gain G at the signal wavelength shall be calculated as:
S (with el. mod .) − S (without el. mod.)
out out
G = (linear units)
S (with el. mod .) − S (without el. mod .)
in in
or
S (with el. mod .) − S (without el. mod.)
out out
G = 5 log  (dB)
S (with el. mod .) − S (without el. mod .)
in in
NOTE 1 The small-signal regime is the range of input signal power sufficiently small so that the OA under test
operates in the linear regime. This regime can be established by plotting G versus the averaged input optical
signal power. The linear regime demands averaged input optical signal power to be in the range where the gain
is quite independent from it (see Figure 2). An averaged input optical signal power ranging from –30 dBm to –

40 dBm is generally well within this range. In the saturated regime, the signal power is large enough to well
suppress the ASE.
NOTE 2 The measurement error can be better than ±0,4 dB (‡), depending mainly on the optical detector and
electrical spectrum analyzer linearities.
the gain G at the signal wavelength shall be calculated either in linear units using Formula
(3) or in units of dB using Formula (4).
SS−
out-m out-0
G=
(3)
S − S
in-m in-0
SS−
out-m out-0
G= 5 log
 (4)
S − S
in-m in-0
where
S is the modulated electrical power measured by the electrical spectrum analyzer at
out-m
the OA output, expressed in mW;
=
S is the modulated electrical power measured by the electrical spectrum analyzer at
in-m
the OA input, expressed in mW;
S is the electrical power measured by the electrical spectrum analyzer at the OA
out-0
output without intensity modulation of the optical source, expressed in mW;
S is the electrical power measured by the electrical spectrum analyzer at the OA input
in-0
without intensity modulation of the optical source, expressed in mW.
NOTE 2 The measurement uncertainty can be better than ±0,4 dB (‡), depending mainly on the linearity of the
optical detector and the linearity of the electrical spectrum analyzer.
c) Reverse gain: as in b).
d) Maximum gain: calculate the gain values at the different wavelengths, as in b). The
maximum gain shall be given by the highest of all these gain values.
e) Maximum gain wavelength: calculate the maximum gain as in d). The maximum gain
wavelength shall be that wavelength at which the maximum small-signal gain occurs.
f) Maximum gain variation with temperature: Under consideration.
f) Gain wavelength band: calculate the maximum gain as in d). Identify those wavelengths at
which the gain is N dB below the maximum gain. The gain wavelength band shall be given
by the wavelength interval(s), comprised between those wavelengths, within which the gain
is between the maximum gain value and a value N dB below the maximum gain.
NOTE 3 A value of N = 3 is typically applied.
g) Gain variation: calculate the maximum gain as in d). Calculate the minimum gain as the
lowest of all gain values within the specified measurement wavelength range. The gain
variation shall be the difference between the maximum and the minimum gain values.
i) Gain stability: Under consideration.
h) Polarization-dependent gain: calculate the gain values at the different states of polarization,
as in b). Identify the maximum gain, G , and the minimum gain, G , as the highest and
max min
the lowest of all these gain values, respectively. The polarization-dependent gain ∆G ,
p
expressed in dB, is calculated using Formula (5).
ΔGG− G
(5)
p max min
where
G is the maximum gain, expressed in dB;
max
G is the minimum gain, expressed in dB.
min
NOTE 4 G is defined as the same as G in b). G is defined as G in which P is replaced by P .
min max out-min out-max
NOTE 5 ∆G does not necessarily indicate the possible maximum variation of the polarization dependency.
p
This is because the attenuation through the OA under test is maximum only when each input state of polarization
simultaneously yields maximum attenuation in each component in the OA under test.
NOTE 6 The measurement error can be within ±0,4 dB (‡), depending mainly on thepolarization dependency
of the optical detector.
k) Large-signal output stability: under consideration.
l) Saturation output power: under consideration.
m) Maximum input signal power: under consideration.
n) Maximum output signal power: under consideration.
o) Input power range: under consideration.
p) Output power range: under consideration.
q) Maximum total output power: under consideration.
=
8 Test results
The following test results shall be presented recorded.
a) Nominal output signal power:
the following details shall be presented recorded:
1) arrangement of the test set-up;
2) spectral linewidth (full width at half maximum) of the optical source;
3) indication of the optical pump power and possibly driving current of pump lasers for
OFAs and injection current for SOAs (if applicable);
4) operating temperature (if required);
5) time-averaged input signal optical power P ;
in
6) resolution bandwidth of the electrical spectrum analyzer;
7) wavelength of the measurement;
8) nominal output signal power levels;
9) change in the state of polarization given to the input signal light.
b) Gain: the details 1) - 7) from a) shall be presented recorded in addition to:
8) gain.
NOTE 1 Parameters Details 5) and 8) can be replaced with the gain versus the averaged input signal optical
power curve.
c) Reverse gain: the details 1) to 7), previously listed for the gain, shall be presented recorded
and, in addition:
89) reverse gain.
NOTE 2 Parameters Details 5) and 8) can be replaced with the reverse small-signal gain versus the averaged
input signal optical power curve.
d) Maximum gain: the details 1) to 7), previously listed for the gain, shall be presented recorded
and, in addition to:
8) wavelength range of the measurement;
9) wavelength measurement accuracy;
10) maximum gain.
NOTE 3 Parameters Details 5) and 10) can be replaced with the maximum gain versus the averaged input
signal optical power curve.
e) Maximum gain wavelength: the details 1) to 7), previously listed for the gain, shall be
presented recorded and, in addition to:
8) wavelength range of the measurement;
9) wavelength measurement accuracy;
10) maximum gain wavelength.
NOTE 4 Parameters Details 8) and 10) can be replaced with the gain versus input signal wavelength curve.
f) Maximum gain variation with temperature: Under consideration.
f) Gain wavelength band: The details 1) to 7), previously listed for the gain, shall be presented
recorded and, in addition to:
8) wavelength range of the measurement;
9) wavelength measurement accuracy;
10) gain wavelength band;
11) the value of N chosen for the determination of the wavelength bandwidth.
NOTE 5 Parameters Details 8) and 10) and 11) can be replaced with the gain versus input signal wavelength
curve.
g) Gain variation: The details 1) to 7), previously listed for the gain, shall be presented
recorded and, in addition:
8) wavelength range of the measurement;
9) wavelength measurement accuracy;
10) gain variation.
NOTE 6 Parameters Details 8) and 10) can be replaced with the gain versus input signal wavelength curve.
i) Gain stability: Under consideration.
h) Polarization-dependent gain: The details 1) to 8), previously listed for the gain, shall be
presented recorded and, in addition:
9) polarization dependency of the optical detector;
10) the maximum and minimum gain, G and G ;
max min
11) polarization-dependent gain;
12) change in the state of polarization given to the input signal light.
k) Large-signal output stability: under consideration.
l) Saturation output power: under consideration.
m) Maximum input signal power: under consideration.
n) Maximum output signal power: under consideration.
o) Input power range: under consideration.
p) Output power range: under consideration.
q) Maximum total output power: under consideration.

Bibliography
IEC 60793-1-1, Optical fibres – Part 1-1: Measurement methods and test procedures – General
and guidance
IEC 60825-1, Safety of laser products - Part 1: Equipment classification and requirements and
user's guide
IEC 60825-2, Safety of laser products - Part 2: Safety of optical fibre communication systems
(OFCS)
IEC 60874-1, Connectors for optical fibres and cables – Part 1: Generic specification
IEC 61931, Fibre optic – Terminology
IEC 61290 (all parts), Optical amplifiers - Test methods
IEC 61290-10 (all parts), Optical amplifiers - Test methods - Part 10: Multichannel parameters
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
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IEC 61290-1-2 ®
Edition 3.0 2026-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
...