We present a fiber-optic temperature sensor with a single-crystal sapphire fiber as the light guide and a sapphire wafer as the sensing element. Temperature is determined by measurement of the thermal dependence of the wafer's optical thickness by use of white-light interferometry. We applied digital signal processing techniques to analyze the sensor's spectrum. A prototype sensor was tested to 1600 °C and demonstrated excellent reproducibility. An accuracy of ±0.2% full scale was obtained. The sensor is simple, small, and flexible, with potential advantages of batch fabrication and easy calibration.
© 2005 Optical Society of America
Yizheng Zhu, Zhengyu Huang, Fabin Shen, and Anbo Wang, "Sapphire-fiber-based white-light interferometric sensor for high-temperature measurements," Opt. Lett. 30, 711-713 (2005)