Light intensity modulation temperature sensor based on U-shaped bent single-mode fiber

A light intensity modulation temperature sensor based on U-shaped bent single-mode fiber is presented, which has been employed in a ratiometric power measurement scheme and a FBG temperature calibration system. The sensor is a U-shaped fiber with double coating, i.e., inner absorptive India ink coating and outer nickel protection coating. An approximately linear relationship between the bend loss of the fiber and temperature is obtained, when the temperature of the sensor is varied from 0 °C to 80 °C. The proposed sensor shows a bend loss response of 0.023 dB/°C and a temperature resolution of 0.5 °C.