Encapsulated and coated photonic crystal fibre sensor for temperature measurements up to 1000°C

Fibre optic sensors for high temperature applications have significant advantages over their non-optical counterparts, because they are passive and immune to electromagnetic interference, can be multiplexed, have higher sensitivity, better accuracy, etc. The development of such sensors has emerged owing to their large number of industrial and R&D applications. Fabry-Perot and modal interferometer in photonic crystal fibre (PCF) have been proposed to overcome the drawbacks of Ge-doped fibre sensors for high temperatures. The inconvenience of PCF based devices is their fragility, especially at high operating temperatures. A proper packaging that protects the fibre sensing head and at the same time maintains its optical performance is thus required, this being the aim of our work here presented.