Performance stability of the sapphire fiber and cladding under high temperature

This paper concentrates on the performance stability of sapphire fiber thermometer probe and the development of an alumina fiber cladding durable under high temperature and of high transparency. Analysis was made on the performance stability of sapphire fiber probe under high temperature when using different kinds of protective tube. It is found that direct contacting of the fiber with protective tubes is the most important factor that result in performance deterioration and the dirtying of evaporating substance is another important factor. Then it is applicable to design a suitable protective tube to assure the performance stability.