This technical report describes two methods for the measurement of the sensitivity of single – mode optical fibres to high-power damage at bends:<\/p>\n
te st method 1 \u2013 Failure time characterisation as a function of the launch power and bend conditions (bend angle and bend diameter);<\/p>\n<\/li>\n
t est method 2 \u2013 Equilibrium temperature measurement .<\/p>\n<\/li>\n<\/ul>\n
Results from the two methods can only be compared qualitatively.<\/p>\n
The results in this report are predominantly on un -cabled and un-buffered fibres. Cabled and buffered fibres are expected to respond differently , because the outer layers can affect the ageing process. Note also that test method 2 testing cannot be applied to buffered or cabled fibres.<\/p>\n
These methods do not constitute a routine test to be used in the evaluation of optical fibre.<\/p>\n
The parameters derived from the two methods are not intended to be specified within a detailed fibre specification.<\/p>\n
The catastrophic failure modes arising and which are described in this document in general occur at bending radii much smaller than specified in the single -mode fibre specification IEC 60793-2-50 or than would be recommended based on mechanical reliability considerations alone.<\/p>\n
This report includes several annexes, including a discussion on the rationale for the approaches adopted, metrics for assessment, guidance, examples and some conclusions from initial studies.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 4<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 6<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | 1 Scope 2 Normative references <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | 3 Background <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 4 Test procedures 4.1 Safety 4.1.1 Safety issues 4.1.2 Eye safe working 4.1.3 Risk of fire\/flame 4.1.4 Risk of atmospheric pollution from coating by-products 4.1.5 Risk of fibre fuse initiation <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 4.1.6 Risk of damage to downstream components 4.1.7 Risk avoidance 4.2 General 4.3 Apparatus 4.3.1 Light source 4.3.2 Isolator <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 4.3.3 Bend jig 4.3.4 Receiver 4.3.5 Attenuator 4.3.6 Computer 4.3.7 Camera 4.3.8 Thermal imaging camera 4.3.9 Oven Figures Figure 1 \u2013 Example of experimental layout <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 4.3.10 Sample 4.4 Test method 1 \u2013 Failure time characterization as a function of the launch power and bend conditions (bend angle and diameter) 4.4.1 Description and procedure <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 4.4.2 General comments and conclusions on test method 1 Figure 2 \u2013 Damage results for fibre \u2018G\u2019 <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 4.4.3 Reported items for test method 1 4.5 Test method 2 \u2013 Equilibrium temperature measurement 4.5.1 General <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | Figure 3 \u2013Example of time evolution of catastrophic high-power loss and related maximum temperature reached by the coating near to the top of the bent fibre (apex) <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4.5.2 Coating heating measurements and power lost at bend Figure 4 \u2013 Sample FLIR camera output of the fibre bent under high power Figure 5 \u2013 Dependence of the coating equilibrium temperature as a function of launched power and bend diameter for an IEC B1.2\/ITU-T G.654 single-mode fibre (see reference [10]) <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 4.5.3 Analysis \u2013 test method 2: equilibrium temperature <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 4.5.4 Test conditions for test method 2 Figure 6a \u2013 Calculated from experimental test data at 1 360 nm Figure 6b \u2013 Extrapolated for 1 550 nm Figure 6c \u2013 Extrapolated for 1 625 nm Figure 6 \u2013 Maximum safe powers for 25 year life time as a function of bend radius enabling a safe coating temperature of ~80 \u00b0C for four single-mode fibre (sub-) categories <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 4.5.5 Conclusions on test method 2 4.5.6 Reported items for test method 2 <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 5 Conclusions <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | Annex A (informative) Robustness of fibres against damage fromexposure to high power at bends <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | Figure A.1 \u2013 Clamping arrangements for high-power damage testing in 180\u00b0 bends Figure A.2 \u2013 Clamping arrangement for high-power damage testing in 90\u00b0 bends <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | Figure A.3 \u2013 Typical R1 failure characteristics with a loss of greater than 10 dB Figure A.4 \u2013 Typical R2 failure characteristics Figure A.5 \u2013 A schematic illustration of the three regimes <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Figure A.6 \u2013 Monitor signal changes \u2013 Typical for an R1 failure Figure A.7 \u2013 Monitor signal changes \u2013 Typical for an R2 failure <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Figure A.8 \u2013 Damage results for fibre sample \u2018D\u2019 Figure A.9 \u2013 High-power damage results at 90\u00b0 and 180\u00b0 for fibre \u2018D\u2019 <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Figure A.10 \u2013 Time to failure versus bend diameter at different launched powers <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | Figure A.11 \u2013 Bend loss performance at 180\u00b0 (and 90\u00b0 for comparison) for fibre \u2018D\u2019 Figure\u00a0A.12 \u2013 Power limitation for primary coated fibre <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | Figure\u00a0A.13 \u2013 Comparison of power limitation for primary and secondary coated fibre \u2018D\u2019 <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | Figure\u00a0A.14 \u2013 Maximum optical power ensuring a 25 year lifetime and 180\u00b0 bendloss versus bend diameter (from reference [10]) Figure\u00a0A.15 \u2013 Maximum optical power ensuring a 25 year lifetime versus 180\u00b0 bend loss <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Figure A.16 \u2013 180( 2-point OSA bend loss for fibre \u2018D\u2019 Figure A.17 \u2013 180( 2-point bend loss at 1 480 nm for fibre \u2018D\u2019 <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Figure A.18 \u2013 2-point bend loss for fibre \u2018D\u2019 at various angles <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Figure A.19 \u2013 180( 2-point bend loss at 1 480\u00a0nm for a range of fibres <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure A.20 \u2013 Time to failure versus inverse of equilibrium temperature using an IEC\u00a0B1.2\/ITU-T G.654 single-mode fibre for bend diameters varying from 4\u00a0mm to 10\u00a0mm and launched power in the range 0,8 W to 3,2 W Figure\u00a0A.21 \u2013 Effect of baking primary coated fibre \u2018C\u2019 (reference [15]) in an oven at constant temperature <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Figure A.22 \u2013 Time to failure for different coatings as a function of bend radius Tables Table A.1 \u2013 Dependence of high-power damage on power entering coating <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Guidelines for the measurement of high-power damage sensitivity ofsinglemode fibre to bends. Guidance for the interpretation of results<\/b><\/p>\n |