Spectral characteristics and effects of heat treatment on intrinsic Nd-doped fiber thermometer probes

Abstract
A detailed investigation of the practical spectroscopic features and the effect of prolonged exposure to elevated temperatures of an intrinsic Nd:doped fiber optic thermometer probe using the fluorescence decay time technique has been carried out. Results have shown the optimum length for the doped fiber and a maximum operating temperature of 750 °C, beyond which a range of high-temperature “annealing” effects are seen. These are discussed in light of the operation of the thermometers over the range from −196 to 750 °C and potentially above.