It is very critical to develop sensor that can operate in high temperature and chemically harsh environments. Sapphire (Al₂O₃) material, which possesses a melting point of 2050°C and a wide transmission wavelength region as high as ~3.5μm, has been demonstrated to be an ideal candidate for high temperature fiber-based environmental sensing applications. Under harsh environment, the performance of conventional blackbody radiation based sapphire fiber high temperature sensor could be easily affected due to the lack of cladding. In this paper, a fiber-optic temperature sensor with a single-crystal sapphire fiber as the light guide and a high temperature ceramic coating as the sensing element as well as the protection layer was presented. The radiance emitted from the ceramic coating is used to measure the temperature, and it is transmitted to optical receiver through the sapphire fiber. This ceramic coating greatly improved the stability and dynamical range of pyrometer. Preliminary experimental results demonstrated that the sensor is very promising for measuring ultra-high temperature up to 1900°C in the harsh environment.

Date Published: 24 August 2006
PDF: 8 pages
Proc. SPIE 6314, Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications XII, 63140Z (24 August 2006); doi: 10.1117/12.681040

Published in SPIE Proceedings Vol. 6314:
Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications XII
Francis T. S. Yu; Ruyan Guo; Shizhuo S. Yin, Editor(s)