IEC 61300-3-14:2025

IEC 61300-3-14 ®
Edition 4.0 2025-12
INTERNATIONAL
STANDARD
REDLINE VERSION
Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures -
Part 3-14: Examinations and measurements - Error and repeatability of the
attenuation settings of a variable optical attenuator
ICS 33.180.20 ISBN 978-2-8327-0933-7
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CONTENTS
FOREWORD . 2
1 Scope . 1
2 Normative references . 4
3 Terms, definitions and abbreviated terms . 4
3.1 Terms and definitions. 4
3.2 Abbreviated terms . 4
4 General description . 5
5 Apparatus . 7
5.1 Light source (SLS) and launch conditions . 8
5.2 Detector (D) Power meter (PM) . 8
5.3 Reference fibre (RF) . 8
5.4 Temporary joint (TJ) . 8
6 Measurement procedure . 9
6.1 Measurement set-up . 9
6.2 Measurement procedure . 9
7 Calculation . 10
7.1 Attenuation error for VOAs with absolute calibration . 10
7.2 Attenuation error for VOAs with relative calibration . 10
7.3 Maximum deviation of attenuation error from setting for all attenuation levels
settings . 10
7.4 Repeatability of attenuation . 10
7.5 Measurement report uncertainty considerations . 11
8 Details to be specified and reported . 12
8.1 General .
8.2 Light source and launch condition .
8.3 Detector .
8.4 Reference fibre .
8.5 Temporary joint .
8.6 DUT .
8.7 Measurement procedure .
8.8 Measurement uncertainty .
8.9 Others .
Annex A (informative) Example of a sample measurement record report . 14
Annex B (informative) Measurement method of hysteresis characteristics . 15
B.1 General .
B.1 Measurement procedure . 15
B.2 Calculation . 15
Bibliography . 17

Figure 1 – Measured versus nominal attenuation .
Figure 1 – Absolute versus relative calibrated attenuation settings . 6
Figure 2 – Measurement set-up . 9

Table 1 – Contributors to measurement uncertainty on attenuation error . 12
Table A.1 – Device performance specifications versus actual performance . 14
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Fibre optic interconnecting devices and passive components -
Basic test and measurement procedures -
Part 3-14: Examinations and measurements - Error and repeatability
of the attenuation settings of a variable optical attenuator

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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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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 61300-3-14:2014. 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 61300-3-14 has been prepared by subcommittee 86B: Fibre optic interconnecting devices
and passive components, of IEC technical committee 86: Fibre optics. It is an International
Standard.
This fourth edition cancels and replaces the third edition published in 2014. This edition
constitutes a technical revision
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of IEC 61315, Calibration of fibre-optic power meters as normative reference;
b) addition of Clause 3 containing terms, definitions and abbreviated terms;
c) addition of notes for permission of repeatability definition with 2σ;
d) correction of error in Figure 1 a) and Figure 1 b);
e) addition of a clear statement on EF launch condition requirement for MM source;
f) change of “Detector” to “Power meter”;
g) combination of Clause 7 and Clause 8 into a new Clause 8 titled “Details to be specified and
reported”;
h) addition of uncertainty considerations in Clause 7;
i) correction of error in Formula (B.3).
The text of this International Standard is based on the following documents:
Draft Report on voting
86B/5123/FDIS 86B/5151/RVD
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 61300 series, published under the general title, Fibre optic
interconnecting devices and passive components – Basic test and measurement procedures
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.
1 Scope
This part of IEC 61300 provides a method to measure the error and repeatability of the
attenuation value settings of a variable optical attenuator (VOA). There are two control
technologies for VOAs: manually controlled and electrically controlled. This document covers
both VOA control technologies and also both single-mode fibres and multimode fibres VOAs.
For electrically controlled VOAs, the hysteresis characteristics of attenuation are sometimes
important. The hysteresis characteristics can be measured as stated in Annex B.
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 61300-1, Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures - Part 1: General and guidance
IEC 61300-3-4, Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures - Part 3-4: Examinations and measurements - Attenuation
IEC 61315, Calibration of fibre-optic power meters
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61300-1 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
DOP degree of polarization
DUT device under test
LS light source
PM power meter
PDL polarization dependent loss
RF reference fibre
RMS root mean square
TJ temporary joint
VOA variable optical attenuator
4 General description
A variable optical attenuator is adjusted sequentially through a series of nominal attenuation
settings prescribed in the relevant. It is recommended to adjust sequentially through 10 settings
or more in the specific range or as defined in the product specification. For an electrically
controlled VOA, the attenuation is set by applying electrical voltage or current to the device.
There are two categories of VOAs:
– those that can be adjusted to nominal attenuation levels settings;
– those that have no information on the nominal attenuation levels settings.
Some manually controlled VOAs have a scaled dial to indicate the nominal attenuation levels
settings. Some electrically controlled VOAs have a table (or formula) indicating the applied
voltage (or current) corresponding to the nominal attenuation levels settings. This measurement
method of attenuation error and repeatability can only be applied to VOAs which can be
adjusted to nominal attenuation levels settings.
In this type of measurement, the attenuation value is measured at each setting i (i = 1, 2 …n).
This sequence of measurements is repeated a number of times m as prescribed specified in the
relevant specification 7.4. The error of the attenuator at each setting is then given by the
difference between the mean average of the measured values and the nominal value. The
repeatability at each setting is given by a value of plus and minus two or three times the
standard deviation of the measurements.
GenerallyTypically, the nominal attenuation levels settings are provided in different two ways,
i.e. reported as absolute or relative calibrated attenuation calibration levels settings. Figure 1
a) characterizes an attenuator which is calibrated to read the actual or absolute measured
attenuation. Figure 1 b) characterizes an attenuator for which the manufacturer provides the
calibration calibrated results relative to a zero-point setting. When the attenuator is adjusted to
read zero, the actual or measured attenuation will be some value greater than zero.
Figure 1a – Absolute calibration of attenuation

Figure 1b − Calibration relative to zero-point setting
Figure 1 – Measured versus nominal attenuation
a) Absolute calibrated attenuation

b) Relative calibrated to zero-point setting
Figure 1 – Absolute versus relative calibrated attenuation settings
5 Apparatus
5.1 Light source (SLS) and launch conditions
The output power of the light source shall be sufficiently high to permit a sufficiently large
measurement dynamic range with the optical detector used. The output power stability shall be
less than or equal to within ± 0,05 dB over one hour. The dynamic range of the source/ and
detector combination shall be at least 10 dB greater than the absolute value of the maximum
attenuation value to be measured. However, the output power into the fibre shall not exceed
the maximum operating input power rating of the VOA to be tested.
The wavelength and spectral width of the light source shall correspond to the operating
wavelength range and calibration settings of the VOA to be measured. The spectral width is
required to be narrower than the operational wavelength range.
For the measurement of single-mode VOAs, the polarization dependent loss (PDL) may can
influence the error and repeatability of attenuation values. Unless otherwise specified, random
polarization states shall be used or the PDL shall also be characterized.
Other requirements of the light source and launch conditions shall be in accordance with
IEC 61300-3-4. An excitation unit shall be used to satisfy the launch condition defined in
IEC 61300-1, if necessary. Moreover cladding modes shall be stripped as typically achieved by
the fibre coating, so that they do not affect the measurement. Multimode fibre light sources shall
satisfy the launch condition defined in IEC 61300-1. Moreover, cladding modes shall be stripped,
in accordance with IEC 61300-1, so that they do not affect the measurement.
5.2 Detector (D) Power meter (PM)
A high dynamic range optical power meter should be used for the detector. Its wavelength range
shall be wider than the operating wavelength range of the VOA to be measured. In order to
make measurements with low uncertainty, the linearity of the optical power meter is most
important for the error and repeatability of VOA measurements. The minimum resolution of the
detector shall be ≤0,01 Db ≤ 0,005 dB. The nonlinearity of power meter shall be within ± 0,015
over the measurement dynamic range. The nonlinearity calibration or verification, or both of the
power meter shall be in accordance with IEC 61315.
Other requirements of detector relating to the power meter shall be in accordance with
IEC 61300-3-4.
5.3 Reference fibre (RF)
In order to measure the output power of the light source, a reference fibre is used. The reference
fibre shall be of the same performance type and category as the pigtail fibre of the VOA to be
measured.
5.4 Temporary joint (TJ)
This is a method, device or mechanical fixture for temporarily aligning two fibre ends into a
stable, reproducible, low-loss joint. It is used when direct connection of the device under test
(DUT) to the measurement system is not achievable by a standard connector. It may can for
example, be a precision V-groove, vacuum chuck, a micromanipulator, or a fusion or mechanical
splice. The temporary joint shall be stable to within ± 10 % of the measurement uncertainty
required in dB over the time taken to measure P and P P , where P is the reference power
0 n i 0
level before VOA insertion as shown in Figure 2 a) and P is the power level after VOA insertion
i
with a given attenuation setting (i) as shown in Figure 2 b).
A suitable refractive index matching material may can be used to improve the stability of the
TJ.
Patchcords with direct connection to the light source may can be used and the use of TJs is not
mandatory.
6 Measurement procedure
6.1 Measurement set-up
Figure 2 shows the measurement set-up.
The position of the fibres during the measurement shall remain fixed between the measurement
of P and P P to avoid changes in attenuation due to bending losses.
0 n i
a) Measurement of the reference power

b) Measurement of attenuation
Figure 2 – Measurement set-up
6.2 Measurement procedure
The measurement procedure is as follows:
a) Assemble the measurement set-up as shown in Figure 2 a) and measure P .
b) Insert the VOA to be measured (DUT) into the measurement set-up as shown in Figure 2 b).
c) Adjust the DUT to the lowest attenuation level setting and record the power level of P .
d) Increase the attenuation of the DUT to the next lowest attenuation level setting and record
the power level of P .
e) Continue to measure and record the power levels of P , P , …P , increasing the attenuation
3 4 n
levels settings to the next higher attenuation level setting for each step.
f) Repeat steps c) to e) and record a second set of readings P (2) to P (2).
1 n
g) Repeat step f) for the number of times m specified in the relevant specification m times as
specified in 7.1 and 7.4.
7 Calculation
7.1 Attenuation error for VOAs with absolute calibration
Calculate the error of the ith attenuation setting using Formula (1):
δa a−A (dB) (1)
i ii
where
a (n) = −10log10[P(n)/P ] (dB) (2)
i i 0
m
a = a ( j) (dB) (3)
i ∑ i
m
j =1
1 m
a = aj (dB) (2)
( )
∑
ii
j=1
m
a j = −10 log Pj /P (dB)
( ) ( ) (3)
ii 0

and where A is the ith nominal attenuation setting (dB).
i
7.2 Attenuation error for VOAs with relative calibration
Calculate the error of the ith attenuation setting using Formula (4):
δa=a−−a A (dB)
(4)
i i 1 i
where a is the mean value of the zero-point attenuation.
7.3 Maximum deviation of attenuation error from setting for all attenuation levels
settings
The maximum deviation of attenuation from setting error for all attenuation levels settings can
be calculated using Formula (5):
δa = max ( δa )
(dB) (5)
max i =1−n i
δa = max δa
( ) (dB)
(5)
i
max
=
where i is from 1 to n.
7.4 Repeatability of attenuation
Calculate the 3σ-repeatability of attenuation by
∆a = ± 3 σ
(dB) (6)
i i
∆=ak± σ (dB) (6)
i i
where k is equal to 2 or 3, and σ is the standard deviation of the measurements calculated
i
using Formula (7):
n
(dB) (7)
σ = (a ( j) − a )
i ∑ i i
n
j =1
1 m
(7)
σ aj−a (dB)
( ( ) )
i ∑ ii
j=1
m
A minimum of m = 10 measurements at each setting are recommended should be carried out
for each setting to provide a reasonable estimate of σ .
i
7.5 Measurement report uncertainty considerations
The following values shall be described in the measurement report. Annex A shows an example
of a sample measurement record.
th
– i nominal attenuation level, A ;
i
th
– error of the i attenuation levels, δa ;
i
– maximum deviation of attenuation from setting for all attenuation levels, δa ;
max
– repeatability of ith attenuation levels, ∆a .
i
It is recommended that a chart plotting the measurement result such as those shown in
Figure 1a or Figure 1b is included in the measurement report.
VOA's technologies are described in IEC 60869-1:2018, Annex G. The VOA's main features are
the linearity and variable attenuation range, the wavelength dependency, the PDL, and the
multiple path interference (MPI).
Table 1 shows the main considered contributors to measurement uncertainty on attenuation
error, induced from DUT (VOAs), light sources and power meters.
=
Table 1 – Contributors to measurement uncertainty on attenuation error
Parameters VOA (DUT) Light sources Power meter
Linearity Variable attenuation range Stability of output power Dynamic range of detection
(maximum and minimum
detection power); nonlinearity
in measurement range
Repeatability Repeatability of attenuation n/a n/a
setting
Wavelength Wavelength dependency of Centre wavelength Wavelength dependency of
dependency attenuation (centroid); spectral width responsibility
(RMS)
PDL PDL DOP Polarization dependent
responsibility
MPI Fabri-Perot and Mach- Coherency Fabri-Perot based
Zehnder based
8 Details to be specified and reported
8.1 General
The following details, as applicable, shall be specified in the relevant specification and/or
recorded in the measurement report.
8.2 Light source and launch condition
– Type of light source
– Centre wavelength
– Spectral width
– Output power
– Power stability during measurement
– Type of measurement method of polarization dependency (when used)
– Type of mode filter and launch condition (when used)
8.3 Detector
– Type of detector
– Dynamic range of sensitivity
– Linearity of sensitivity
– Polarization dependency of sensitivity
8.4 Reference fibre
– Category of reference fibre
– Fibre length
– Fibre jacket type
8.5 Temporary joint
– Type of temporary joint
– Nominal return loss of temporary joint
– Nominal attenuation of temporary joint
8.6 DUT
– Device performance specifications versus actual performance
8.7 Measurement procedure
– Attenuation settings measured
– Number of measurements at each setting (m)
8.8 Measurement uncertainty
8.9 Others
– Deviations from this measuring procedure
The following details shall be specified as noted below and shall be reported in the test report.
Annex A shows an example of a sample test report.
• Measurement equipment specification and set-up (see Clause 5):
– light source – type, centre wavelength (centroid), and spectral width (RMS);
– power meter – type, model and serial number;
– reference fibre – category, fibre length, and fibre jacket type;
– temporary joint – type, nominal return loss, and nominal attenuation.
• Final examinations, measurements, and calculations and performance requirements (see
Clause 6 and Clause 7):
– number of measurements at each setting (m);
– attenuation settings measured (results should be plotted in a graph such as in
Figure 1 a) or Figure 1 b);
– ith nominal attenuation setting, A ;
i
– error of the ith attenuation setting, δa ;
i
δa
– maximum attenuation error from setting for all attenuation setting; ;
max
– repeatability of ith attenuation settings, ∆a ,with kσ (k = 2 or 3);
i
• Additional pass-or-fail criteria;
• Deviations from test procedure.
Annex A
(informative)
Example of a sample measurement record report
The following example is for illustration only and does not indicate recommended apparatus or
measuring conditions.
• Source description: 1 307 nm Fabry-Perot laser source.
• Excitation unit description: none.
• Detector description: InGaAs power sensor.
• Reference fibre: cut-back section of attenuator input port.
• Reference connector set: none.
• Temporary joint: fusion splice.
• Reference fibre lengths: 0,25 m.
• Pigtail fibre length of VOA: 1 m.
• Preconditioning procedure: Standard atmospheric conditions for 24 h as per IEC 61300 -1
• Attenuation settings to be measured: minimum setting, 10 dB, 20 dB, 30 dB, 40 dB, 50 dB
and 60 dB.
• Number of measurements at each setting: m = 10.
• Deviations from this test procedure: P measured by cut-back of attenuator input port.
• Device performance specifications versus actual performance: see Table A.1 below.
Table A.1 – Device performance specifications versus actual performance
Setting Nominal values Measured values
(i) Attenuation Error Repeatability Attenuation Error Repeatability
A δa ∆a a δa Δa
i i i i i i
dB dB ±dB dB dB ±dB
1 1,4 < 0,5 < 0,3 1,7 +0,3 0,11
2 10 < 0,5 < 0,3 9,8 -0,2 0,16
3 20 < 0,5 < 0,4 19,7 -0,3 0,23
4 30 < 0,5 < 0,4 30,0 0,0 0,30
5 40 < 0,5 < 0,5 40,3 +0,3 0,33
6 50 < 0,5 < 0,5 50,4 +0,4 0,39
7 60 < 0,5 < 0,6 60,4 +0,4 0,41
Maximum – − − − +0,4 0,41
Annex B
(informative)
Measurement method of hysteresis characteristics
B.1 General
For electrically controlled VOAs, the hysteresis characteristics of attenuation are sometimes
important. The hysteresis characteristics can be measured as follows.
B.1 Measurement procedure
The measurement procedure is as follows:
a) proceed using steps a) and b) specified in 6.2;
b) adjust the DUT to the lowest attenuation level setting and record the power level of P
1;
c) increase the attenuation of the DUT to the next lowest attenuation level setting and record
the power level of P ;
d) continue to measure and record the power levels of P , P , …P , increasing the attenuation
3 4 n
levels settings to the next higher attenuation level setting for each step;
e) after measuring and recording the power level of P (1), decrease the attenuation of the DUT
n
to the next lower attenuation level setting and record the power of P’n-1(1). Repeat steps of
(f) for the number of times m specified in the relevant specification;
f) continue to measure and record the power levels of P’n-2(1) to P’1(1), decreasing the
attenuation levels settings to the next lower attenuation level setting for each step;
g) repeat steps b) to f) and record a second set of readings P (2) to P (2) and P’n-1(2) to
1 n
P’1(2);
h) repeat step g) for the number of times m specified in the relevant specification m times as
specified in 7.4.
B.2 Calculation
The hysteresis of the attenuation is calculated using Formula (B.1):
δa max a−a ' (dB)
( ) (B.1)
hys ii
11≤≤in−
where
(dB) (B.2)
a' (n) = −10log[P' (n)/ P ]
i i 0
m
(dB) (B.3)
a = a '( j)
i i
∑
m
j=1
=
m
a ' = aj' (dB) (B.2)
( )
∑
ii
j=1
m
 
(dB)
a' (j) = −10log P' (j) /P
(B.3)
i
10  i 0 
Bibliography
IEC 60869-1:2018, Fibre optic interconnecting devices and passive components - Fibre optic
passive power control devices - Part 1: Generic specification

___________
IEC 61300-3-14 ®
Edition 4.0 2025-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures -
Part 3-14: Examinations and measurements - Error and repeatability of the
attenuation settings of a variable optical attenuator

Dispositifs d'interconnexion et composants passifs fibroniques - Procédures
fondamentales d'essais et de mesures -
Partie 3-14: Examens et mesures - Erreur et répétabilité des positions
d'affaiblissement d'un affaiblisseur optique variable
ICS 33.180.20  ISBN 978-2-8327-0898-9

CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms, definitions and abbreviated terms . 4
3.1 Terms and definitions. 4
3.2 Abbreviated terms . 4
4 General description . 5
5 Apparatus . 7
5.1 Light source (LS) and launch conditions . 7
5.2 Power meter (PM) . 7
5.3 Reference fibre (RF) . 7
5.4 Temporary joint (TJ) . 7
6 Measurement procedure . 8
6.1 Measurement set-up . 8
6.2 Measurement procedure . 8
7 Calculation . 8
7.1 Attenuation error for VOAs with absolute calibration . 8
7.2 Attenuation error for VOAs with relative calibration . 9
7.3 Maximum attenuation error from setting for all attenuation settings . 9
7.4 Repeatability of attenuation . 9
7.5 Measurement uncertainty considerations . 9
8 Details to be specified and reported . 10
Annex A (informative) Example of a sample measurement report . 11
Annex B (informative) Measurement method of hysteresis characteristics . 12
B.1 Measurement procedure . 12
B.2 Calculation . 12
Bibliography . 13

Figure 1 – Absolute versus relative calibrated attenuation settings . 6
Figure 2 – Measurement set-up . 8

Table 1 – Contributors to measurement uncertainty on attenuation error . 10
Table A.1 – Device performance specifications versus actual performance . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Fibre optic interconnecting devices and passive components -
Basic test and measurement procedures -
Part 3-14: Examinations and measurements - Error and repeatability
of the attenuation settings of a variable optical attenuator

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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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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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) 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.
IEC 61300-3-14 has been prepared by subcommittee 86B: Fibre optic interconnecting devices
and passive components, of IEC technical committee 86: Fibre optics. It is an International
Standard.
This fourth edition cancels and replaces the third edition published in 2014. This edition
constitutes a technical revision
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of IEC 61315, Calibration of fibre-optic power meters as normative reference;
b) addition of Clause 3 containing terms, definitions and abbreviated terms;
c) addition of notes for permission of repeatability definition with 2σ;
d) correction of error in Figure 1 a) and Figure 1 b);
e) addition of a clear statement on EF launch condition requirement for MM source;
f) change of “Detector” to “Power meter”;
g) combination of Clause 7 and Clause 8 into a new Clause 8 titled “Details to be specified and
reported”;
h) addition of uncertainty considerations in Clause 7;
i) correction of error in Formula (B.3).
The text of this International Standard is based on the following documents:
Draft Report on voting
86B/5123/FDIS 86B/5151/RVD
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 61300 series, published under the general title, Fibre optic
interconnecting devices and passive components – Basic test and measurement procedures
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.
...

IEC 61300-3-14 ®
Edition 4.0 2025-12
NORME
INTERNATIONALE
Dispositifs d'interconnexion et composants passifs fibroniques - Procédures
fondamentales d'essais et de mesures -
Partie 3-14: Examens et mesures - Erreur et répétabilité des positions
d'affaiblissement d'un affaiblisseur optique variable
ICS 33.180.20  ISBN 978-2-8327-0898-9

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

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CH-1211 Geneva 20 www.iec.ch
Switzerland
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

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SOMMAIRE
AVANT-PROPOS . 2
1 Domaine d’application . 4
2 Références normatives . 4
3 Termes, définitions et abréviations . 4
3.1 Termes et définitions . 4
3.2 Abréviations . 4
4 Description générale . 5
5 Appareillage . 7
5.1 Source de rayonnement lumineux (LS) et conditions d’injection . 7
5.2 Appareil de mesure de la puissance (PM) . 7
5.3 Fibre de référence (RF) . 7
5.4 Jonction temporaire (TJ) . 7
6 Procédure de mesure . 8
6.1 Montage de mesure . 8
6.2 Procédure de mesure . 8
7 Calculs . 9
7.1 Erreur d’affaiblissement concernant les VOA avec étalonnage absolu . 9
7.2 Erreur d’affaiblissement concernant les VOA avec étalonnage relatif . 9
7.3 Erreur maximale d’affaiblissement du réglage pour toutes les positions
d’affaiblissement . 9
7.4 Répétabilité de l’affaiblissement . 10
7.5 Considérations sur l’incertitude de mesure . 10
8 Détails à spécifier et à consigner dans le rapport d’essai . 11
Annexe A (informative) Exemple de rapport de mesures . 12
Annexe B (informative) Méthode de mesure des caractéristiques d’hystérésis . 13
B.1 Procédure de mesure . 13
B.2 Calcul . 13
Bibliographie . 14

Figure 1 – Positions d’affaiblissement étalonné absolu par rapport à l’affaiblissement
étalonné relatif . 6
Figure 2 – Montage de mesure . 8

Tableau 1 – Contributeurs à l’incertitude de mesure sur l’erreur d’affaiblissement . 10
Tableau A.1 – Spécifications de performance du dispositif par rapport à la performance
réelle . 12

COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
Dispositifs d’interconnexion et composants passifs fibroniques -
Procédures fondamentales d’essais et de mesures -
Partie 3-14: Examens et mesures - Erreur et répétabilité des positions
d’affaiblissement d’un affaiblisseur optique variable

AVANT-PROPOS
1) La Commission Électrotechnique internationale (IEC) est une organisation mondiale de normalisation composée
de l’ensemble des comités électrotechniques nationaux (Comités nationaux de l’IEC). L’IEC a pour objet de
favoriser la coopération internationale pour toutes les questions de normalisation dans les domaines de
l’électricité et de l’électronique. À cet effet, l’IEC – entre autres activités – publie des Normes internationales,
des Spécifications techniques, des Rapports techniques, des Spécifications accessibles au public (PAS) et des
Guides (ci-après dénommés "Publication(s) de l’IEC"). Leur élaboration est confiée à des comités d’études, aux
travaux desquels tout Comité national intéressé par le sujet traité peut participer. Les organisations
internationales, gouvernementales et non gouvernementales, en liaison avec l’IEC, participent également aux
travaux. L’IEC collabore étroitement avec l’Organisation Internationale de Normalisation (ISO), selon des
conditions fixées par accord entre les deux organisations.
2) Les décisions ou accords officiels de l’IEC concernant les questions techniques représentent, dans la mesure du
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sont représentés dans chaque comité d’études.
3) Les Publications de l’IEC se présentent sous la forme de recommandations internationales et sont agréées
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l’éventuelle mauvaise utilisation ou interprétation qui en est faite par un quelconque utilisateur final.
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mesure possible, à appliquer de façon transparente les Publications de l’IEC dans leurs publications nationales
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6) Tous les utilisateurs doivent s’assurer qu’ils sont en possession de la dernière édition de cette publication.
7) Aucune responsabilité ne doit être imputée à l’IEC, à ses administrateurs, employés, auxiliaires ou mandataires,
y compris ses experts particuliers et les membres de ses comités d’études et des Comités nationaux de l’IEC,
pour tout préjudice causé en cas de dommages corporels et matériels, ou de tout autre dommage de quelque
nature que ce soit, directe ou indirecte, ou pour supporter les coûts (y compris les frais de justice) et les dépenses
découlant de la publication ou de l’utilisation de cette Publication de l’IEC ou de toute autre Publication de l’IEC,
ou au crédit qui lui est accordé.
8) L’attention est attirée sur les références normatives citées dans cette publication. L’utilisation de publications
référencées est obligatoire pour une application correcte de la présente publication.
9) L'IEC attire l'attention sur le fait que la mise en application du présent document peut entraîner l'utilisation d'un
ou de plusieurs brevets. L'IEC ne prend pas position quant à la preuve, à la validité et à l'applicabilité de tout
droit de brevet revendiqué à cet égard. À la date de publication du présent document, l'IEC n'avait pas reçu
notification qu'un ou plusieurs brevets pouvaient être nécessaires à sa mise en application. Toutefois, il y a lieu
d'avertir les responsables de la mise en application du présent document que des informations plus récentes
sont susceptibles de figurer dans la base de données de brevets, disponible à l'adresse https://patents.iec.ch.
L'IEC ne saurait être tenue pour responsable de ne pas avoir identifié de tels droits de brevets.
L'IEC 61300-3-14 a été établie par le sous-comité 86B: Dispositifs d’interconnexion et
composants passifs à fibres optiques, du comité d’études 86 de l’IEC: Fibres optiques. Il s'agit
d'une Norme internationale.
Cette quatrième édition annule et remplace la troisième édition parue en 2014. Cette édition
constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition
précédente:
a) ajout de l’IEC 61315, Étalonnage de wattmètres pour dispositifs à fibres optiques, comme
référence normative;
b) ajout de l’Article 3 contenant des termes, des définitions et des abréviations;
c) ajout de notes relatives à la définition de l’autorisation de répétabilité avec 2σ;
d) correction d’une erreur à la Figure 1 a) et à la Figure 1 b);
e) ajout d'une déclaration claire relative aux exigences des conditions d’injection de flux inscrit
pour la source MM;
f) remplacement de "Détecteur" par "Appareil de mesure de la puissance";
g) regroupement des Articles 7 et 8 dans le nouvel Article 8 intitulé "Détails à spécifier et à
consigner dans le rapport d’essai";
h) ajout de considérations d’incertitude à l’Article 7;
i) correction d’une erreur dans une formule (B.3).
Le texte de cette Norme internationale est issu des documents suivants:
Projet Rapport de vote
86B/5123/FDIS 86B/5151/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à son approbation.
La langue employée pour l’élaboration de cette Norme internationale est l’anglais.
Ce document a été rédigé selon les Directives ISO/IEC, Partie 2, il a été développé selon les
Directives ISO/IEC, Partie 1 et les Directives ISO/IEC, Supplément IEC, disponibles sous
www.iec.ch/members_experts/refdocs. Les principaux types de documents développés par
l'IEC sont décrits plus en détail sous www.iec.ch/standardsdev/publications.
Une liste de toutes les parties de la série IEC 61300, publiées sous le titre général, Dispositifs
d’interconnexion et composants passifs fibronique – Procédures fondamentales d’essais et de
mesures peut être consultée sur le site Web de l’IEC.
Le comité a décidé que le contenu de ce document ne sera pas modifié avant la date de stabilité
indiquée sur le site web de l'IEC sous webstore.iec.ch dans les données relatives au document
recherché. À cette date, le document sera
– reconduit,
– supprimé, ou
– révisé.
1 Domaine d’application
La présente partie de l’IEC 61300 fournit une méthode pour mesurer l’erreur et la répétabilité
des réglages des valeurs d’affaiblissement d’un affaiblisseur optique variable (VOA). Il existe
deux technologies de commande pour les VOA, la commande manuelle et la commande
électrique. Le présent document couvre les deux technologies de commande VOA et les VOA
des fibres unimodales et multimodales. Pour les VOA à commande électrique, les
caractéristiques d’hystérésis de l’affaiblissement sont parfois importantes. Les caractéristiques
d’hystérésis peuvent être mesurées comme indiqué à l’Annexe B.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu'ils constituent, pour tout ou partie
de leur contenu, des exigences du présent document. Pour les références datées, seule
l'édition citée s'applique. Pour les références non datées, la dernière édition du document de
référence s'applique (y compris les éventuels amendements).
IEC 61300-1, Dispositifs d’interconnexion et composants passifs fibroniques - Procédures
fondamentales d’essais et de mesures - Partie 1: Généralités et recommandations
IEC 61300-3-4, Dispositifs d’interconnexion et composants passifs fibroniques - Procédures
fondamentales d’essais et de mesures - Partie 3-4: Examens et mesures - Affaiblissement
IEC 61315, Étalonnage de wattmètres pour dispositifs à fibres optiques
3 Termes, définitions et abréviations
3.1 Termes et définitions
Pour les besoins du présent document, les termes et définitions de l’IEC 61300-1 s’appliquent.
L'ISO et l'IEC tiennent à jour des bases de données terminologiques destinées à être utilisées
en normalisation, consultables aux adresses suivantes:
– IEC Electropedia: disponible à l'adresse https://www.electropedia.org/
– ISO Online browsing platform: disponible à l'adre
...

IEC 61300-3-14 ®
Edition 4.0 2025-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures -
Part 3-14: Examinations and measurements - Error and repeatability of the
attenuation settings of a variable optical attenuator

Dispositifs d'interconnexion et composants passifs fibroniques - Procédures
fondamentales d'essais et de mesures -
Partie 3-14: Examens et mesures - Erreur et répétabilité des positions
d'affaiblissement d'un affaiblisseur optique variable
ICS 33.180.20  ISBN 978-2-8327-0898-9

All rights reserved. Unless otherwise specified, 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 either
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questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
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A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
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informations sur les projets et les publications remplacées
ou retirées. Electropedia - www.electropedia.org
Le premier dictionnaire d'électrotechnologie en ligne au
IEC Just Published - webstore.iec.ch/justpublished monde, avec plus de 22 500 articles terminologiques en
Restez informé sur les nouvelles publications IEC. Just anglais et en français, ainsi que les termes équivalents
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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms, definitions and abbreviated terms . 4
3.1 Terms and definitions. 4
3.2 Abbreviated terms . 4
4 General description . 5
5 Apparatus . 7
5.1 Light source (LS) and launch conditions . 7
5.2 Power meter (PM) . 7
5.3 Reference fibre (RF) . 7
5.4 Temporary joint (TJ) . 7
6 Measurement procedure . 8
6.1 Measurement set-up . 8
6.2 Measurement procedure . 8
7 Calculation . 8
7.1 Attenuation error for VOAs with absolute calibration . 8
7.2 Attenuation error for VOAs with relative calibration . 9
7.3 Maximum attenuation error from setting for all attenuation settings . 9
7.4 Repeatability of attenuation . 9
7.5 Measurement uncertainty considerations . 9
8 Details to be specified and reported . 10
Annex A (informative) Example of a sample measurement report . 11
Annex B (informative) Measurement method of hysteresis characteristics . 12
B.1 Measurement procedure . 12
B.2 Calculation . 12
Bibliography . 13

Figure 1 – Absolute versus relative calibrated attenuation settings . 6
Figure 2 – Measurement set-up . 8

Table 1 – Contributors to measurement uncertainty on attenuation error . 10
Table A.1 – Device performance specifications versus actual performance . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Fibre optic interconnecting devices and passive components -
Basic test and measurement procedures -
Part 3-14: Examinations and measurements - Error and repeatability
of the attenuation settings of a variable optical attenuator

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) 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.
IEC 61300-3-14 has been prepared by subcommittee 86B: Fibre optic interconnecting devices
and passive components, of IEC technical committee 86: Fibre optics. It is an International
Standard.
This fourth edition cancels and replaces the third edition published in 2014. This edition
constitutes a technical revision
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of IEC 61315, Calibration of fibre-optic power meters as normative reference;
b) addition of Clause 3 containing terms, definitions and abbreviated terms;
c) addition of notes for permission of repeatability definition with 2σ;
d) correction of error in Figure 1 a) and Figure 1 b);
e) addition of a clear statement on EF launch condition requirement for MM source;
f) change of “Detector” to “Power meter”;
g) combination of Clause 7 and Clause 8 into a new Clause 8 titled “Details to be specified and
reported”;
h) addition of uncertainty considerations in Clause 7;
i) correction of error in Formula (B.3).
The text of this International Standard is based on the following documents:
Draft Report on voting
86B/5123/FDIS 86B/5151/RVD
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 61300 series, published under the general title, Fibre optic
interconnecting devices and passive components – Basic test and measurement procedures
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.
1 Scope
This part of IEC 61300 provides a method to measure the error and repeatability of the
attenuation value settings of a variable optical attenuator (VOA). There are two control
technologies for VOAs: manually controlled and electrically controlled. This document covers
both VOA control technologies and also both single-mode fibres and multimode fibres VOAs.
For electrically controlled VOAs, the hysteresis characteristics of attenuation are sometimes
important. The hysteresis characteristics can be measured as stated in Annex B.
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 61300-1, Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures - Part 1: General and guidance
IEC 61300-3-4, Fibre optic interconnecting devices and passive components - Basic test and
measurement procedures - Part 3-4: Examinations and measurements - Attenuation
IEC 61315, Calibration of fibre-optic power meters
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61300-1 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
DOP degree of polarization
DUT device under test
LS light source
PM power meter
PDL polarization dependent loss
RF reference fibre
RMS root mean square
TJ temporary joint
VOA variable optical attenuator
4 General description
A variable optical attenuator is adjusted sequentially through a series of nominal attenuation
settings. It is recommended to adjust sequentially through 10 settings or more in the specific
range or as defined in the product specification. For an electrically controlled VOA, the
attenuation is set by applying electrical voltage or current to the device.
There are two categories of VOAs:
– those that can be adjusted to nominal attenuation settings;
– those that have no information on the nominal attenuation settings.
Some manually controlled VOAs have a scaled dial to indicate the nominal attenuation settings.
Some electrically controlled VOAs have a table (or formula) indicating the applied voltage (or
current) corresponding to the nominal attenuation settings. This measurement method of
attenuation error and repeatability can only be applied to VOAs which can be adjusted to
nominal attenuation settings.
In this type of measurement, the attenuation value is measured at each setting i (i = 1, 2 …n).
This sequence of measurements is repeated a number of times m as specified in 7.4. The error
of the attenuator at each setting is then given by the difference between the average of the
measured values and the nominal value. The repeatability at each setting is given by a value
of plus and minus two or three times the standard deviation of the measurements.
Typically, the nominal attenuation settings are reported as absolute or relative calibrated
attenuation settings. Figure 1 a) characterizes an attenuator which is calibrated to read the
absolute measured attenuation. Figure 1 b) characterizes an attenuator for which the
manufacturer provides the calibrated results relative to a zero-point setting. When the
attenuator is adjusted to read zero, the actual or measured attenuation will be some value
greater than zero.
a) Absolute calibrated attenuation

b) Relative calibrated to zero-point setting
Figure 1 – Absolute versus relative calibrated attenuation settings
5 Apparatus
5.1 Light source (LS) and launch conditions
The output power stability shall be within ± 0,05 dB over one hour. The dynamic range of the
source and detector combination shall be at least 10 dB greater than the absolute value of the
maximum attenuation value to be measured. However, the output power into the fibre shall not
exceed the maximum operating input power rating of the VOA to be tested.
The wavelength and spectral width of the light source shall correspond to the operating
wavelength range and calibration settings of the VOA to be measured. The spectral width is
required to be narrower than the operational wavelength range.
For the measurement of single-mode VOAs, the polarization dependent loss (PDL) can
influence the error and repeatability of attenuation values. Unless otherwise specified, random
polarization states shall be used or the PDL shall also be characterized.
Other requirements of the light source and launch conditions shall be in accordance with
IEC 61300-3-4. Multimode fibre light sources shall satisfy the launch condition defined in
IEC 61300-1. Moreover, cladding modes shall be stripped, in accordance with IEC 61300-1, so
that they do not affect the measurement.
5.2 Power meter (PM)
A high dynamic range optical power meter should be used. Its wavelength range shall be wider
than the operating wavelength range of the VOA to be measured. In order to make
measurements with low uncertainty, the linearity of the optical power meter is most important
for the error and repeatability of VOA measurements. The minimum resolution of the detector
shall be ≤ 0,005 dB. The nonlinearity of power meter shall be within ± 0,015 over the
measurement dynamic range. The nonlinearity calibration or verification, or both of the power
meter shall be in accordance with IEC 61315.
Other requirements relating to the power meter shall be in accordance with IEC 61300-3-4.
5.3 Reference fibre (RF)
In order to measure the output power of the light source, a reference fibre is used. The reference
fibre shall be of the same type and category as the pigtail fibre of the VOA to be measured.
5.4 Temporary joint (TJ)
This is a method, device or mechanical fixture for temporarily aligning two fibre ends into a
stable, reproducible, low-loss joint. It can for example, be a precision V-groove, vacuum chuck,
a micromanipulator, or a fusion or mechanical splice. The temporary joint shall be stable to
within ± 10 % of the measurement uncertainty required in dB over the time taken to measure
and P , where P is the reference power level before VOA insertion as shown in Figure 2 a)
P
0 i 0
is the power level after VOA insertion with a given attenuation setting (i) as shown in
and P
i
Figure 2 b).
A suitable refractive index matching material can be used to improve the stability of the TJ.
Patchcords with direct connection to the light source can be used and the use of TJs is not
mandatory.
6 Measurement procedure
6.1 Measurement set-up
Figure 2 shows the measurement set-up.
The position of the fibres during the measurement shall remain fixed between the measurement
of P and P to avoid changes in attenuation due to bending losses.
0 i
a) Measurement of the reference power

b) Measurement of attenuation
Figure 2 – Measurement set-up
6.2 Measurement procedure
The measurement procedure is as follows:
a) Assemble the measurement set-up as shown in Figure 2 a) and measure P .
b) Insert the VOA to be measured (DUT) into the measurement set-up as shown in Figure 2 b).
c) Adjust the DUT to the lowest attenuation setting and record the power level of P .
d) Increase the attenuation of the DUT to the next lowest attenuation setting and record the
power level of P .
e) Continue to measure and record the power levels of P , P , …P , increasing the attenuation
3 4 n
settings to the next higher attenuation setting for each step.
f) Repeat steps c) to e) and record a second set of readings P (2) to P (2).
1 n
g) Repeat step f) m times as specified in 7.1 and 7.4.
7 Calculation
7.1 Attenuation error for VOAs with absolute calibration
Calculate the error of the ith attenuation setting using Formula (1):
δa a−A (dB)
(1)
i ii
where
1 m
a = aj (dB)
( ) (2)
ii∑
j=1
m
=
a(j)=−10 log Pj( ) /P (dB)
(3)
ii 0

A
and where is the ith nominal attenuation setting (dB).
i
7.2 Attenuation error for VOAs with relative calibration
Calculate the error of the ith attenuation setting using Formula (4):
δa=a−−a A (dB)
(4)
i i 1 i
a
where is the mean value of the zero-point attenuation.
7.3 Maximum attenuation error from setting for all attenuation settings
The maximum attenuation error for all attenuation settings can be calculated using Formula (5):
δa = max δa (dB)
( ) (5)
i
max
where i is from 1 to n.
7.4 Repeatability of attenuation
Calculate the repeatability of attenuation by
∆=ak± σ (dB)
(6)
i i
where k is equal to 2 or 3, and σ is the standard deviation of the measurements calculated
i
using Formula (7):
1 m
(7)
σ aj−a (dB)
( ( ) )
i ∑ ii
j=1
m
A minimum of m = 10 measurements should be carried out for each setting to provide a
reasonable estimate of σ .
i
7.5 Measurement uncertainty considerations
VOA's technologies are described in IEC 60869-1:2018, Annex G. The VOA's main features are
the linearity and variable attenuation range, the wavelength dependency, the PDL, and the
multiple path interference (MPI).
=
Table 1 shows the main considered contributors to measurement uncertainty on attenuation
error, induced from DUT (VOAs), light sources and power meters.
Table 1 – Contributors to measurement uncertainty on attenuation error
Parameters VOA (DUT) Light sources Power meter
Linearity Variable attenuation range Stability of output power Dynamic range of detection
(maximum and minimum
detection power); nonlinearity
in measurement range
Repeatability Repeatability of attenuation n/a n/a
setting
Wavelength Wavelength dependency of Centre wavelength Wavelength dependency of
dependency attenuation (centroid); spectral width responsibility
(RMS)
PDL PDL DOP Polarization dependent
responsibility
MPI Fabri-Perot and Mach- Coherency Fabri-Perot based
Zehnder based
8 Details to be specified and reported
The following details shall be specified as noted below and shall be reported in the test report.
Annex A shows an example of a sample test report.
• Measurement equipment specification and set-up (see Clause 5):
– light source – type, centre wavelength (centroid), and spectral width (RMS);
– power meter – type, model and serial number;
– reference fibre – category, fibre length, and fibre jacket type;
– temporary joint – type, nominal return loss, and nominal attenuation.
• Final examinations, measurements, and calculations and performance requirements (see
Clause 6 and Clause 7):
– number of measurements at each setting (m);
– attenuation settings measured (results should be plotted in a graph such as in
Figure 1 a) or Figure 1 b);
– ith nominal attenuation setting, A ;
i
– error of the ith attenuation setting, δa ;
i
– maximum attenuation error from setting for all attenuation setting; δa ;
max
– repeatability of ith attenuation settings, ∆a ,with kσ (k = 2 or 3);
i
• Additional pass-or-fail criteria;
• Deviations from test procedure.

Annex A
(informative)
Example of a sample measurement report
The following example is for illustration only and does not indicate recommended apparatus or
measuring conditions.
• Source description: 1 307 nm Fabry-Perot laser source.
• Excitation unit description: none.
• Detector description: InGaAs power sensor.
• Reference fibre: cut-back section of attenuator input port.
• Reference connector set: none.
• Temporary joint: fusion splice.
• Reference fibre lengths: 0,25 m.
• Pigtail fibre length of VOA: 1 m.
• Attenuation settings to be measured: minimum setting, 10 dB, 20 dB, 30 dB, 40 dB, 50 dB
and 60 dB.
• Number of measurements at each setting: m = 10.
• Deviations from this test procedure: P measured by cut-back of attenuator input port.
• Device performance specifications versus actual performance: see Table A.1 below.
Table A.1 – Device performance specifications versus actual performance
Setting Nominal values Measured values
(i) Attenuation Error Repeatability Attenuation Error Repeatability
A δa ∆a a δa Δa
i i i i i i
dB dB ±dB dB dB ±dB
1 1,4 < 0,5 < 0,3 1,7 +0,3 0,11
2 10 < 0,5 < 0,3 9,8 -0,2 0,16
3 20 < 0,5 < 0,4 19,7 -0,3 0,23
4 30 < 0,5 < 0,4 30,0 0,0 0,30
5 40 < 0,5 < 0,5 40,3 +0,3 0,33
6 50 < 0,5 < 0,5 50,4 +0,4 0,39
7 60 < 0,5 < 0,6 60,4 +0,4 0,41
Maximum +0,4 0,41
– − − −
Annex B
(informative)
Measurement method of hysteresis characteristics
B.1 Measurement procedure
The measurement procedure is as follows:
a) proceed using steps a) and b) specified in 6.2;
b) adjust the DUT to the lowest attenuation setting and record the power level of P
1;
c) increase the attenuation of the DUT to the next lowest attenuation setting and record the
power level of P ;
d) continue to measure and record the power levels of P , P , …P , increasing the attenuation
3 4 n
settings to the next higher attenuation setting for each step;
e) after measuring and recording the power level of P (1), decrease the attenuation of the DUT
n
to the next lower attenuation setting and record the power of P’n-1(1);
f) continue to measure and record the power levels of P’n-2(1) to P’1(1), decreasing the
attenuation settings to the next lower attenuation setting for each step;
g) repeat steps b) to f) and record a second set of readings P
...