Improved understanding of high-power damage phenomena at fibre bends through analytical temperature mapping

摘要

The full characterisation of a fibre's sensitivity to high power damage is time consuming and expensive. The fibre's initial equilibrium temperature under bending is a practical metric that can be used to mitigate the risk of damage by keeping this temperature below that which causes accelerated ageing of the coating. Modelling of the temperature distribution can be used to filter fibre and coating designs before proceeding with more expensive experimental evaluation. The inclusion of stress terms that modify the refractive index in the BPM analysis of bend loss enables the bend loss to be modelled more accurately. This together with the appropriate thermal boundary conditions on the fibre surface substantially improves the accuracy of computing the temperature distribution within the coatings of a bent fibre.