Silicon-Carbide-Based Extreme Environment Temperature Sensor Using Wavelength-Tuned Signal Processing

A wavelength-tuned signal-processing approach is proposed for enabling direct unambiguous temperature measurement in a free-space targeted single-crystal silicon carbide (SiC) temperature sensor. The approach simultaneously exploits the 6H SiC fundamental Sellmeier equation-based wavelength-sensitive refractive index change in combination with the classic temperature-dependent refractive index change and the material thermal-expansion path-length change to encode SiC chip temperature with wavelength. Presently, the technique is useful for fast coarse temperature measurement as demonstrated from room temperature to 10000C using a 10-peak count wavelength-tuned measurement with a 0.31 nm total wavelength change. This coarse technique can be combined with the previously presented two-wavelength signal-processing temperature measurement approach to simultaneously deliver a wide temperature range and a highresolution temperature sensor. Applications for the sensor range from power plants to materials processing facilities. © 2008 Optical Society of America