Sapphire Fiber High-Temperature Tip Sensor With Multilayer Coating

Multilayers of dielectric oxide coated at the end of sapphire fiber act as Fabry-Perot interferometer, and high-temperature sensing elements are proposed and demonstrated. Broadband tungsten halogen lamp is used to generate interferometric fringes from which the temperature-dependent optical thickness change of the coatings can be accurately determined. Experimental investigation shows that the sensor exhibits a temperature responsibility of 40.7 pm/°C when the ambient temperature changes from 400 °C to 1000 °C. The sensor is proved to be simple in configuration and easy for batch fabrication.