IEC TR 61292-4:2023

IEC TR 61292-4 ®
Edition 4.0 2023-01
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Optical amplifiers –
Part 4: Maximum permissible optical power for the damage-free and safe use of
optical amplifiers, including Raman amplifiers

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IEC TR 61292-4 ®
Edition 4.0 2023-01
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Optical amplifiers –
Part 4: Maximum permissible optical power for the damage-free and safe use of
optical amplifiers, including Raman amplifiers
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.10; 33.180.30 ISBN 978-2-8322-6365-5

– 2 – IEC TR 61292-4:2023 RLV © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
1 Scope and object . 8
2 Normative references . 8
3 Terms, definitions, and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms . 8
4 Maximum transmissible optical power to keep fibres damage-free . 9
4.1 General . 9
4.2 Fibre fuse and its propagation . 10
4.3 Loss-induced heating at connectors or splices . 11
4.4 Connector endface damage induced by dust/contamination . 12
4.5 Fibre coat burn/melt induced by tight fibre bending . 15
4.6 Summary of the fibre damage . 16
5 Maximum transmissible optical power to keep eyes and skin safe . 16
5.1 Maximum transmissible exposure (MPE) on the surface of eye and skin . 16
5.2 Maximum permissible optical power in the fibre for the safety of eye and skin. 17
5.2.1 General .
5.2.1 Power limit . 17
5.2.2 Need for APR . 18
5.2.3 Wavelengths . 19
5.2.4 Locations . 19
5.2.5 Nominal ocular hazard distance (NOHD). 19
5.2.6 Power reduction times . 19
5.2.7 Medical aspects of the safety of eyes and skin in existing standards . 21
6 Maximum optical power permissible for optical amplifiers from the viewpoint of
fibre damage as well as eye and skin safety . 22
7 Conclusion . 22
Annex A (informative) General information for optical fibre fuse . 23
A.1 Introductory remark . 23
A.2 Generating mechanism . 23
A.3 Void formation mechanism . 27
A.4 Propagation characteristic of a fibre fuse . 27
A.5 Prevention and termination . 29
A.5.1 General . 29
A.5.2 Prevention methods . 29
A.5.3 Termination methods . 30
A.6 Additional safety information . 32
A.7 Conclusion . 33
Bibliography . 34

Figure 1 – Experimental set-up for fibre fuse propagation . 10
Figure 2 – Connection loss versus temperature increase . 12
Figure 3 – Test set-up . 13
Figure 4 – Surface condition contaminated with metal filings, before the test . 14

Figure 5 – Variation of power attenuation during test at several power input values for
plugs contaminated with metal filings . 14
Figure 6 – Polishing surface condition contaminated with metal filing, after test . 14
Figure 7 – Thermo viewer image of tightly bent SMF with optical power of 3 W at
1 480 nm . 15
Figure 8 – Temperature of the coating surface of SMFs against bending with optical
power of 3 W at 1 480 nm . 16
Figure 9 – Maximum permissible power in the fibre against APR power reduction time . 21
Figure A.1 – Front part of the fibre fuse damage generated in the optical fibre . 23
Figure A.2 – SiO absorption model . 25
Figure A.3 – Calculated fibre fuse propagation behaviour simulated with the SiO
absorption model . 26
Figure A.4 – Series of optical micrographs showing damage generated by 9,0 W

1 480 nm laser light suggesting a mechanism of periodic void formation . 27
Figure A.5 – Images of fibre fuse ignition taken with an ultra-high-speed camera and
an optical micrograph of the damaged fibre. 28
Figure A.6 – Power density dependence of the fibre-fuse propagation velocity . 29
Figure A.7 – Optical micrographs showing front part of the fibre fuse damage
generated in SMF-28 fibres with various laser intensities (1 480 nm) . 29
Figure A.8 – Principle of the optical fibre fuse passive termination method and
photograph of a fibre fuse terminator using a TEC structure. 30
Figure A.9 – Photograph of hole-assistantassisted fibre and fibre fuse termination
using a hole-assistantassisted fibre . 31
Figure A.10 – Example of fibre fuse active termination scheme . 32
Figure A.11 – Transformation of electrical signal by optical fibre fuse . 32

Table 1 – Threshold power of fibre fuse propagation for various fibres . 10
Table 2 – Measurement conditions. 12
Table 3 – Examples of power limits for optical fibre communication systems having
automatic power reduction to reduce emissions to a lower hazard level . 17
Table 4 – Location types within an optical fibre communication system and their typical

installations . 19

– 4 – IEC TR 61292-4:2023 RLV © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL AMPLIFIERS –
Part 4: Maximum permissible optical power for the damage-free
and safe use of optical amplifiers, including Raman amplifiers

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