IEC TR 62316:2017
(Main)Guidance for the interpretation of OTDR backscattering traces for single-mode fibres
Guidance for the interpretation of OTDR backscattering traces for single-mode fibres
IEC/TR 62316:2017 which is a Technical Report, aims to provide guidelines for the interpretation of backscattering traces, as obtained by traditional optical time domain reflectometers (OTDRs) – not including polarization OTDRs – for single-mode fibres. Also, backscattered power effects are discussed in case of unidirectional trace. Full description of the test measurement procedure can be found in Annex C of IEC 60793-1-40:2001. This third edition cancels and replaces the second edition published in 2007. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a. the scope has been extended to include single-mode fibres;
b. backscattered power effects are discussed in case of unidirectional trace, including so-called losers and gainers.
c. example of apparent splice loss evaluation for unidirectional OTDR measurements has been added:
d. description of launch and tail cords have been added;
e. figures have been improved.
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IEC TR 62316 ®
Edition 3.0 2017-07
TECHNICAL
REPORT
colour
inside
Guidance for the interpretation of OTDR backscattering traces
for single-mode fibres
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IEC TR 62316 ®
Edition 3.0 2017-07
TECHNICAL
REPORT
colour
inside
Guidance for the interpretation of OTDR backscattering traces
for single-mode fibres
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.10 ISBN 978-2-8322-4553-8
– 2 – IEC TR 62316 © IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Backscattering phenomenon . 6
4.1 Rayleigh scattering . 6
4.2 Fresnel reflections and dead zone fibres . 6
5 Measurement of the backscattered power (OTDR) . 7
5.1 General . 7
5.2 Representation of the backscattered power. 7
5.3 Noise and perturbations . 8
6 Interpretation of a backscattering trace . 8
6.1 General . 8
6.2 Launch cord . 9
6.3 Tail cord . 9
6.4 Unidirectional trace . 9
6.4.1 General . 9
6.4.2 Slope as the attenuation coefficient of a fibre . 10
6.4.3 Impurity and discontinuity . 10
6.4.4 Pulse width . 10
6.4.5 Polarization effects . 10
6.5 Bi-directional trace . 11
6.5.1 General . 11
6.5.2 Attenuation uniformity . 11
6.5.3 MFD uniformity . 12
6.6 Splice loss evaluation . 12
6.6.1 General . 12
6.6.2 Event measurement methods . 13
6.6.3 Apparent losers and gainers . 14
6.6.4 Example of apparent splice loss evaluation for uni-directional OTDR
measurements . 17
7 Uncertainties, deviation and resolution . 18
7.1 General . 18
7.2 Attenuation coefficient measurements . 18
7.3 Fault locations . 19
Bibliography . 21
Figure 1 – Unidirectional OTDR trace showing splice and/or macro bend loss. 9
Figure 2 – Idealized unidirectional OTDR traces corresponding to a non-reflective
splice between two fibres . 13
Figure 3 – OTDR traces for similar or different fibre types with different MFD and/or
different backscatter properties . 14
Figure 4 – Loss in unidirectional OTDR measurements as function of the MFD
difference between two spliced fibres. 15
IEC TR 62316 © IEC 2017 – 3 –
Figure 5 – Theoretical power through splice loss due to MFD difference (with ω =
9µm) . 16
a) Mean spice loss measured from B6 to B1.3 fibre . 17
b) Mean spice loss measured from B1.3 to B6 fibre . 18
Figure 6 – Apparent cumulative unidirectional backscattering mismatch distribution for
six splice combinations of B1.3 and B6 reported in Table 1 . 18
Figure 7 – Schematic drawing of a fibre with two consecutive defects 1 and 2 . 19
Table 1 – Summary for six fibre splice combinations of B1.3 and B6 based on popular
1 310 nm MFD fibre distributions . 17
– 4 – IEC TR 62316 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDANCE FOR THE INTERPRETATION OF OTDR BACKSCATTERING
TRACES FOR SINGLE-MODE FIBRES
FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a Technical Report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 62316, which is a Technical Report, has been prepared by subcommittee 86A: Fibres
and cables, of IEC technical committee 86: Fibre optics.
This third edition cancels and replaces the second edition published in 2007. It constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the scope has been extended to include single-mode fibres;
a) backscattered power effects are discussed in case of unidirectional trace, including
so-called losers and gainers.
b) example of apparent splice loss evaluation for unidirectional OTDR measurements has
been added:
IEC TR 62316 © IEC 2017 – 5 –
c) description of launch and tail cords have been added;
d) figures have been improved.
The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
86A/1754/DTR 86A/1768A/RVC
Full information on the voting for the approval of this technical report 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.
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 th
...
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