Calibration of fibre-optic power meters

IEC 61315:2019 is available as IEC 61315:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 61315:2019 is applicable to instruments measuring radiant power emitted from sources that are typical for the fibre-optic communications industry. These sources include laser diodes, light emitting diodes (LEDs) and fibre-type sources. Both divergent and collimated radiations are covered. This document defines the calibration of power meters to be performed by calibration laboratories or by power meter manufacturers. This third edition cancels and replaces the second edition published in 2005. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) update of terms and definitions; b) update of 5.1, including Table 1 (new type of source); c) update of Annex A; d) addition of Annex B on dB conversion. Keywords: Fibre-optic power meters

Kalibrierung von Lichtwellenleiter-Leistungsmessgeräten

Étalonnage de wattmètres pour dispositifs à fibres optiques

IEC 61315:2019 est disponible sous forme de IEC 61315:2019 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.L'IEC 61315:2019 s'applique aux appareils qui mesurent la puissance rayonnante émise par des sources typiques pour l'industrie des communications par fibres optiques. Ces sources comprennent les diodes laser, les diodes émettant de la lumière (LED) et les sources fibrées. Le rayonnement divergent ainsi que le rayonnement collimaté sont couverts par le présent document. Ce dernier définit l'étalonnage des wattmètres à effectuer par des laboratoires d'étalonnage ou par des fabricants de wattmètres. Cette troisième édition annule et remplace la deuxième édition parue en 2005. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) mise à jour des termes et définitions; b) mise à jour du 5.1, y compris le Tableau 1 (nouveau type de source); c) mise à jour de l'Annexe A; d) ajout d'une Annexe B sur la conversion en dB. Mots-clés : wattmètres pour dispositifs à fibres optiques

Umerjanje optičnih vlakenskih merilnikov moči (IEC 61315:2019)

Ta dokument se uporablja za instrumente merjenja moči sevanja, ki ga oddajajo viri, značilni za industrijo optičnih komunikacij. Ti viri vključujejo laserske diode, svetleče diode (LED) in vire vlakenskega tipa. Zajeta so divergentna in kolimirana sevanja. Ta dokument opredeljuje umerjanje merilnikov moči, ki ga izvajajo laboratoriji za umerjanje ali proizvajalci merilnikov moči.

General Information

Status
Published
Publication Date
16-May-2019
Technical Committee
Drafting Committee
Current Stage
6060 - Document made available
Due Date
17-May-2019
Completion Date
17-May-2019

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SLOVENSKI STANDARD
SIST EN IEC 61315:2019
01-julij-2019
Nadomešča:
SIST EN 61315:2006
Umerjanje optičnih vlakenskih merilnikov moči (IEC 61315:2019)
Calibration of fibre-optic power meters (IEC 61315:2019)
Kalibrierung von Lichtwellenleiter-Leistungsmessern (IEC 61315:2019)
Etalonnage de wattmètres pour dispositifs à fibres optiques (IEC 61315:2019)
Ta slovenski standard je istoveten z: EN IEC 61315:2019
ICS:
33.140 Posebna merilna oprema za Special measuring
uporabo v telekomunikacijah equipment for use in
telecommunications
33.180.10 (Optična) vlakna in kabli Fibres and cables
SIST EN IEC 61315:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 61315:2019
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SIST EN IEC 61315:2019
EUROPEAN STANDARD EN IEC 61315
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2019
ICS 33.140; 33.180.10 Supersedes EN 61315:2006
English Version
Calibration of fibre-optic power meters
(IEC 61315:2019)

Étalonnage de wattmètres pour dispositifs à fibres optiques Kalibrierung von Lichtwellenleiter-Leistungsmessgeräten

(IEC 61315:2019) (IEC 61315:2019)

This European Standard was approved by CENELEC on 2019-05-03. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,

Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 61315:2019 E
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SIST EN IEC 61315:2019
EN IEC 61315:2019 (E)
European foreword

The text of document 86/533/CDV, future edition 3 of IEC 61315, prepared by IEC/TC 86 "Fibre

optics" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN IEC 61315:2019.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2020-02-03

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2022-05-03

document have to be withdrawn
This document supersedes EN 61315:2006.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 61315:2019 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards

indicated:
IEC 61040:1990 NOTE Harmonized as EN 61040:1992 (not modified)
IEC 60793-1-1 NOTE Harmonized as EN 60793-1-1
IEC 60793-1-43:2015 NOTE Harmonized as EN 60793-1-43:2015 (not modified)
IEC 60825-1 NOTE Harmonized as EN 60825-1
IEC 60825-2 NOTE Harmonized as EN 60825-2
IEC 61280-4-1 NOTE Harmonized as EN 61280-4-1
IEC 61300-3-2:2009 NOTE Harmonized as EN 61300-3-2:2009 (not modified)
IEC 60359:2001 NOTE Harmonized as EN 60359:2002 (not modified)
ISO/IEC 17025 NOTE Harmonized as EN ISO/IEC 17025
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SIST EN IEC 61315:2019
EN IEC 61315:2019 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60793-2 - Optical fibres - Part 2: Product EN 60793-2 -
specifications - General
IEC/TR 61931 1998 Fibre optic - Terminology - -
ISO/IEC Guide 98-3 2008 Uncertainty of measurement - Part 3: - -
Guide to the expression of uncertainty in
measurement (GUM:1995)
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SIST EN IEC 61315:2019
IEC 61315
Edition 3.0 2019-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Calibration of fibre-optic power meters
Étalonnage de wattmètres pour dispositifs à fibres optiques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.140; 33.180.10 ISBN 978-2-8322-6640-3

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

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

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

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ....................................................................................................... 7

3 Terms and definitions....................................................................................................... 7

4 Preparation for calibration .............................................................................................. 15

4.1 Organization.......................................................................................................... 15

4.2 Traceability ........................................................................................................... 15

4.3 Advice for measurements and calibrations ............................................................. 15

4.4 Recommendations to users ................................................................................... 16

5 Absolute power calibration ............................................................................................. 16

5.1 Calibration methods .............................................................................................. 16

5.2 Establishing the calibration conditions ................................................................... 17

5.3 Calibration procedure ............................................................................................ 18

5.4 Calibration uncertainty ........................................................................................... 19

5.4.1 General ......................................................................................................... 19

5.4.2 Uncertainty due to the setup ........................................................................... 19

5.4.3 Uncertainty of the reference meter ................................................................. 20

5.4.4 Correction factors and uncertainty caused by the change of conditions ........... 21

5.4.5 Uncertainty due to the spectral bandwidths ..................................................... 24

5.5 Reporting the results ............................................................................................. 25

6 Measurement uncertainty of a calibrated power meter .................................................... 26

6.1 Overview ............................................................................................................... 26

6.2 Uncertainty at reference conditions ........................................................................ 26

6.3 Uncertainty at operating conditions ........................................................................ 26

6.3.1 General ......................................................................................................... 26

6.3.2 Determination of dependences on conditions .................................................. 27

6.3.3 Ageing ........................................................................................................... 28

6.3.4 Dependence on temperature .......................................................................... 28

6.3.5 Dependence on the power level (nonlinearity)................................................. 28

6.3.6 Dependence on the type of fibre or on the beam geometry ............................. 29

6.3.7 Dependence on the connector-adapter combination ....................................... 30

6.3.8 Dependence on wavelength ........................................................................... 31

6.3.9 Dependence on spectral bandwidth ................................................................ 32

6.3.10 Dependence on polarization ........................................................................... 32

6.3.11 Other dependences ........................................................................................ 33

7 Nonlinearity calibration ................................................................................................... 33

7.1 General ................................................................................................................. 33

7.2 Nonlinearity calibration based on superposition ..................................................... 33

7.2.1 General ......................................................................................................... 33

7.2.2 Procedure ...................................................................................................... 34

7.2.3 Uncertainties.................................................................................................. 35

7.3 Nonlinearity calibration based on comparison with a calibrated power meter .......... 36

7.3.1 General ......................................................................................................... 36

7.3.2 Procedure ...................................................................................................... 36

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7.3.3 Uncertainties.................................................................................................. 37

7.4 Nonlinearity calibration based on comparison with an attenuator ............................ 37

7.5 Calibration of power meter for high power measurement ........................................ 37

Annex A (normative) Mathematical basis for measurement uncertainty calculations .............. 38

A.1 General ................................................................................................................. 38

A.2 Type A evaluation of uncertainty ............................................................................ 38

A.3 Type B evaluation of uncertainty ............................................................................ 39

A.4 Determining the combined standard uncertainty ..................................................... 39

A.5 Reporting .............................................................................................................. 40

Annex B (informative) Linear to dB scale conversion of uncertainties .................................... 41

B.1 Definition of decibel ............................................................................................... 41

B.2 Conversion of relative uncertainties ....................................................................... 41

Bibliography .......................................................................................................................... 42

Figure 1 – Typical spectral responsivity of photoelectric detectors .......................................... 13

Figure 2 – Example of a traceability chain .............................................................................. 14

Figure 3 – Measurement setup for sequential, fibre-based calibration .................................... 17

Figure 4 – Change of conditions and uncertainty .................................................................... 22

Figure 5 – Determining and recording an extension uncertainty .............................................. 27

Figure 6 – Possible subdivision of the optical reference plane into 10 × 10 squares, for

the measurement of the spatial response .............................................................................. 29

Figure 7 – Wavelength dependence of response due to Fabry-Perot type interference ........... 32

Figure 8 – Measurement setup of polarization dependent response ....................................... 32

Figure 9 – Nonlinearity calibration based on superposition ..................................................... 34

Figure 10 – Measurement setup for nonlinearity calibration by comparison ............................. 36

Table 1 – Calibration methods and correspondent typical power ............................................ 16

Table 2 – Nonlinearity ........................................................................................................... 35

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CALIBRATION OF FIBRE-OPTIC POWER METERS
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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 61315 has been prepared by IEC technical committee 86: Fibre

optics.

This third edition cancels and replaces the second edition published in 2005. It constitutes a

technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
a) update of terms and definitions;
b) update of 5.1, including Table 1 (new type of source);
c) update of Annex A;
d) addition of Annex B on dB conversion.
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SIST EN IEC 61315:2019
IEC 61315:2019 © IEC 2019 – 5 –
The text of this International Standard is based on the following documents:
CDV Report on voting
86/533/CDV 86/540A/RVC

Full information on the voting for the approval of this International Standard can be found in the

report on voting indicated in the above table.

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

In this document, the following print types are used:
– terms defined in the document: in italic type.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

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INTRODUCTION

Fibre-optic power meters are designed to measure optical power from fibre-optic sources as

accurately as possible. This capability depends largely on the quality of the calibration process.

In contrast to other types of measuring equipment, the measurement results of fibre-optic

power meters usually depend on many conditions of measurement. The conditions of

measurement during the calibration process are called calibration conditions. Their precise

description is therefore an integral part of the calibration.

This document defines all of the steps involved in the calibration process: establishing the

calibration conditions, carrying out the calibration, calculating the uncertainty, and reporting the

uncertainty, the calibration conditions and the traceability.

The absolute power calibration describes how to determine the ratio between the value of the

input power and the power meter's result. This ratio is called correction factor. The

measurement uncertainty of the correction factor is combined following Annex A from

uncertainty contributions from the reference meter, the test meter, the setup and the

procedure.

The calculations go through detailed characterizations of individual uncertainties. It is important

to know that
a) some uncertainties are type B estimations, experience-based,

b) a detailed uncertainty analysis is usually only done once for each power meter type under

test, and all subsequent calibrations are usually based on this one-time analysis, using the

appropriate type A measurement contributions evaluated at the time of the calibration, and

c) some of the individual uncertainties are simply considered to be part of a checklist, with an

actual value which can be neglected.

Clause 5 defines absolute power calibration, which is mandatory for calibration reports

referring to this document.

Clause 6 describes the evaluation of the measurement uncertainty of a calibrated power meter

operated within reference conditions or within operating conditions. It depends on the

calibration uncertainty of the power meter as calculated in 5.4, the conditions and its

dependence on the conditions. It is usually performed by manufacturers in order to establish

specifications and is not mandatory for reports referring to this document. One of these

dependences, the nonlinearity, is determined in a separate calibration (Clause 7).

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IEC 61315:2019 © IEC 2019 – 7 –
CALIBRATION OF FIBRE-OPTIC POWER METERS
1 Scope

This document is applicable to instruments measuring radiant power emitted from sources that

are typical for the fibre-optic communications industry. These sources include laser diodes,

light emitting diodes (LEDs) and fibre-type sources. Both divergent and collimated radiations

are covered. This document defines the calibration of power meters to be performed by

calibration laboratories or by power meter manufacturers.
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 60793-2, Optical fibres – Part 2: Product specifications – General
IEC TR 61931:1998, Fibre optic – Terminology

ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of

uncertainty in measurement (GUM:1995)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC TR 61931 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
accredited calibration laboratory

calibration laboratory authorized by the appropriate national organization to issue calibration

certificates with a minimum specified uncertainty, which demonstrate traceability to national

standards (3.14)
3.2
adjustment

set of operations carried out on an instrument in order that it provides given indications

corresponding to given values of the measurand

Note 1 to entry: When the instrument is made to give a null indication corresponding to a null value of the

measurand, the set of operations is called zero adjustment.
Note 2 to entry: For more information, see ISO/IEC Guide 99:2007, 3.11.

[SOURCE: IEC 60050-311:2001, 311-03-16, modified – The words "of a measuring instrument"

have been deleted from the term, and Note 2 to entry has been added.]
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3.3
calibration

set of operations that establish, under specified conditions, the relationship between the values

of quantities indicated by a measuring instrument and the corresponding values realized by

measurement standards

Note 1 to entry: The result of a calibration permits either the assignment of values of measurands to the

indications or the determination of corrections with respect to indications.

Note 2 to entry: A calibration may also determine other metrological properties such as the effect of influence

quantities.

Note 3 to entry: The result of a calibration may be recorded in a document, sometimes called a calibration

certificate or a calibration report.
Note 4 to entry: See also ISO/IEC Guide 99:2007, 2.39.
3.4
calibration conditions
conditions of measurement in which the calibration is performed
3.5
centroidal wavelength
power-weighted mean wavelength of a light source in vacuum

Note 1 to entry: For a continuous spectrum, the centroidal wavelength is defined as:

p λ λdλ
( )
λ = (1)
total

For a spectrum consisting of discrete lines, the centroidal wavelength is defined as:

λ = (2)
∑ i
where
p(λ) is the power spectral density of the source, for example, in W/nm;
λ is the vacuum wavelength of the i discrete line;
P is the power of the i discrete line, for example, in W;
P is the total power, for example, in W.
total

Note 2 to entry: The above integrals and summations theoretically extend over the entire spectrum of the light

source. However, it is usually sufficient to perform the integral or summation over the spectrum where the spectral

density p(λ) or power P is higher than 0,1 % of the maximum spectral density p(λ) or power P .

i i
3.6
correction factor

numerical factor by which the uncorrected result of a measurement is multiplied to compensate

for systematic error
Note 1 to entry: This note applies to the French language only.
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3.7
detector

element of the power meter that transduces the radiant optical power into a measurable,

usually electrical, quantity

Note 1 to entry: In this document, the detector is assumed to be connected with the optical input port by an optical

path.
Note 2 to entry: For more information, see ISO/IEC Guide 99:2007, 3.9.
3.8
deviation

relative difference between the power measured by the test meter (3.32) P and the

DUT
reference power P :
ref
PP−
DUT ref
D= (3)
ref
Note 1 to entry: This note applies to the French language only.
3.9
excitation

description of the distribution of optical power between the modes in the fibre

Note 1 to entry: In context with multimode fibres, the fibre excitation is described by

a) the spot diameter (3.31) on the surface of the fibre end, and
b) the numerical aperture (3.17) of the radiation emitted from the fibre.

Single-mode fibres are generally assumed to be excited by only one mode (the fundamental mode).

3.10
instrument state
set of parameters that can be chosen on an instrument

Note 1 to entry: Typical parameters of the instrument state are the optical power range, the wavelength setting,

the display measurement unit and the output from which the measurement result is obtained (for example, display,

interface bus, analogue output).
3.11
irradiance

quotient of the incremental radiant power ∂P incident on an element of the reference plane by

the incremental area ∂A of that element:
E= W/m (4)
( )
[Note 1 to entry: For more information, see IEC TR 61931:1998, 2.1.15.
3.12
measurement result

(displayed or electrical) output of a power meter (or standard), after completing all actions

suggested by the operating instructions, for example warm-up, zero adjustment and

wavelength-correction

Note 1 to entry: Measurement result is expressed in watts (W). For the purposes of uncertainty, measurement

results in other units, for example volts, should be converted to watts. Measurement results in decibels (dB) should

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also be converted to watts, because the entire uncertainty accumulation is based on measurement results

expressed in watts. See Annex B.
3.13
measuring range

set of values of measurands for which the error of a measuring instrument is intended to lie

within specified limits

Note 1 to entry: In this document, the measuring range is the range of radiant power (part of the operating range),

for which the uncertainty at operating conditions is specified. The term "dynamic range

...

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