Optical Fiber High-Temperature Sensor Based on Dielectric Films Extrinsic Fabry-Perot Cavity

In this letter, an optic fiber high-temperature sensor with a low-fineness Fabry-Perot cavity formed by dielectric films at the end of multimode fiber is proposed and demonstrated. The sensor is proved to be simple in configuration and low cost for component and easy for batch fabrication. Experimental investigation shows that the sensor exhibits a sensitivity of 5.4 x 10(-3) nm/degrees C when the ambient temperature changes from 250 degrees C to 750 degrees C.