A Compact Sagnac Loop for Temperature Sensing Based on Time-Stretch Method

In this letter, we present a new method to detect temperature based on polarization maintaining fiber (PMF) to construct a Sagnac interference structure in time domain. The working principle of the sensor is introduced in detail, and the feasibility of the scheme is demonstrated by experiment. The temperature sensitivity of this structure is as high as -0.712 nm/°C. Furthermore, in the time domain, an ultrafast temperature sensor with an ultrafast interrogation speed of 200 MHz and a sensitivity of 0.482 ns/ °C is realized. The designed sensing system has potential important value for ammunition temperature monitoring and military industry.