Group-Delay-Based Temperature Sensing in Linearly-Chirped Fiber Bragg Gratings Using a Kerr Phase-Interrogator

We present a novel temperature sensor based on temperature dependence of reflection group-delay in a linearly chirped fiber Bragg grating. The reflection group-delay of a chirped grating changes with temperature leading to a variation in the phase of a sinusoidal optical signal reflected from the grating. A Kerr phase-interrogator converts the phase variation into power variation allowing for high-precision temperature sensing. A temperature sensor with a resolution of 0.0089°C and a sensitivity of 1.122 rad/°C is experimentally demonstrated.