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IEC TR 61282-14
Edition 2.0 2019-07
TECHNICAL
REPORT
colour
inside
Fibre optic communication system design guidelines –
Part 14: Determination of the uncertainties of attenuation measurements in fibre
plants
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IEC TR 61282-14
Edition 2.0 2019-07
TECHNICAL
REPORT
colour
inside
Fibre optic communication system design guidelines –
Part 14: Determination of the uncertainties of attenuation measurements in fibre
plants
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.01 ISBN 978-2-8322-7069-1
– 2 – IEC TR 61282-14:2019 © IEC 2019
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 10
4 Overview of uncertainty . 10
4.1 What is uncertainty? . 10
4.2 Origin of uncertainties . 11
4.3 What may not be considered as uncertainty? . 11
5 Fibre cabling attenuation measurement . 11
5.1 Test methods . 11
5.2 Sources of uncertainty to be considered . 11
5.2.1 Analysis . 11
5.2.2 Uncertainties due to the environment . 14
5.2.3 Uncertainties due to operator skills . 14
5.2.4 Uncertainties due to test methods . 14
5.2.5 Uncertainties due to measuring instruments . 14
5.2.6 Uncertainties due to the setup . 16
5.2.7 Uncertainties due to cabling. 16
6 Uncertainties estimation . 17
6.1 Measurement model. 17
6.2 Accumulation of uncertainties . 19
7 General representation of the equation using sensitivity coefficients . 19
8 Calculation . 23
8.1 Combined standard uncertainty . 23
8.2 Expanded uncertainty . 23
8.3 Determination of the coverage factor k . 23
8.3.1 General approach . 23
8.3.2 Discussion . 23
8.3.3 Typical values of degree of freedom . 24
Annex A (informative) Mathematical basis. 25
A.1 General . 25
A.2 Type A evaluation of uncertainty . 25
A.3 Type B evaluation of uncertainty . 25
A.4 Determining the combined standard uncertainty . 26
A.5 Reporting . 27
Annex B (informative) Test methods . 28
B.1 Test methods as per IEC 61280-4-1 and 61280-4-2 . 28
B.1.1 General . 28
B.1.2 Measurement configuration . 28
B.1.3 One-cord reference configuration . 28
B.1.4 Two-cord reference configuration . 29
B.1.5 Three-cord reference configuration . 29
B.2 Test methods defined in ISO/IEC 14763-3:2014 . 29
B.2.1 General . 29
B.2.2 Channels . 30
B.2.3 Links. 31
Annex C (informative) Uncertainties evaluation . 32
C.1 Type A uncertainties . 32
C.1.1 General . 32
C.1.2 Evaluation of optical source instability and associated uncertainties . 32
C.2 Type B uncertainties . 32
C.2.1 General . 32
C.2.2 Evaluation of the power meter noise . 32
C.2.3 Elements to be considered for power meter stability analysis . 33
C.2.4 Evaluation of the centre wavelength dependence . 33
C.2.5 Spectral width dependence . 35
C.2.6 Evaluation of the uncertainties due to MM launch conditions . 35
C.2.7 Evaluation of the PDL . 36
C.2.8 Uncertainty of absolute power measurement . 37
Annex D (informative) Typical values of uncertainties . 38
Annex E (informative) Linear to dB scale conversion of uncertainties . 40
E.1 Definition of decibel . 40
E.2 Conversion of relative uncertainties . 40
Bibliography . 41
Figure 1 – Fishbone analysis . 13
Figure 2 – Measurement model . 17
Figure B.1 – Measurement configuration . 28
Figure B.2 – One-cord reference measurement . 28
Figure B.3 – Two-cord reference measurement . 29
Figure B.4 – Three-cord reference measurement . 29
Figure B.5 – Measurement on channel . 30
Figure B.6 – Channel reference measurement . 30
Figure B.7 – Link measurement configuration . 31
Figure B.8 – Link reference measurement . 31
Figure C.1 – Typical spectral response of a fibre . 34
Figure C.2 – Uncertainties due to the launch conditions for a given loss . 36
Table 1 – Source of uncertainty (raw list) . 12
Table 2 – Uncertainties due to measuring instruments . 15
Table 3 – Uncertainties due to the setup . 16
Table 4 – Uncertainties due to cabling . 16
Table 5 – Sensitivity coefficients for IEC 61280-4-1 and IEC 61280-4-2 methods . 21
Table 6 – Sensitivity coefficients for ISO/IEC 14763-3:2014 methods. 22
Table 7 – Values of k for different values of ν . 24
Table 8 – Typical values of ν . 24
i
Table C.1 – Spectral attenuation coefficients . 34
– 4 – IEC TR 61282-14:2019 © IEC 2019
Table C.2 – Sensitivity coefficients . 35
Table D.1 – Typical values of uncertainties . 39
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC COMMUNICATION
SYSTEM DESIGN GUIDELINES –
Part 14: Determination of the uncertainties
of attenuation measurements in fibre plants
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 el
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