Fibre optic pressure and temperature sensor for applications in harsh environments

A high-temperature fibre optical sensor for the simultaneous measurement of pressure and temperature has been demonstrated and tested over a pressure range of 60 bar and up to 700°C. The sensor is based on a multi-cavity design and employs a monolithic sapphire transducer element. Excellent linearity with pressure < ±0.1% FS across the whole temperature range and low temperature cross-sensitivity to pressure < ±0.03% FS have been demonstrated.