Er Doped Sapphire Fibre Temperature Sensors Using Upconversion Emission

We report the production of Er:Al₂O₃ and Er:Yb:Al₂O₃ fibres using the LHPG method for application as fibre temperature sensors. Intense upconversion emission in the blue, green and red was observed from these fibres when pumped with a laser diode at 965nm. The lifetime and the integrated intensity of the upconversion signal was characterised as function of laser power and temperature. Results indicate the ratiometric analysis of the integrated intensities provides a suitable transduction mechanism for temperatures up to 1000K.