Single-crystal Sapphire Based Optical Polarimetric Sensor for High Temperature Measurement

Optical sensors have been investigated and widely deployed in industrial andscientific measurement and control processes, mainly due to their accuracy, high sensitivityand immunity to electromagnetic interference and other unique characteristics. They areespecially suited for harsh environments applications, where no commercial electricalsensors are available for long-term stable operations. This paper reports a novel contactoptical high temperature sensor targeting at harsh environments. Utilizing birefringentsingle crystal sapphire as the sensing element and white light interferometric signalprocessing techniques, an optical birefringence based temperature sensor was developed.With a simple mechanically structured sensing probe, and an optical spectrum-codedinterferometric signal processor, it has been tested to measure temperature up to 1600 °Cwith high accuracy, high resolution, and long-term measurement stability.