Temperature Measurement Based on Phase<b>-</b>OFDR With a Narrow Frequency Scanning Range

In recent years, fiber-optic distributed temperature sensors (DTS) based on optical frequency domain reflectometry (OFDR) have shown high accuracy and spatial resolution. In such systems, a large measurement range requires a large scanning range of the laser source, but this usually means a small coherence length, which limits the measurement length. To address this limitation, this study introduces a high-precision temperature sensing method based on polarization mode dispersion and phase measurement. Temperature measurements are achieved by using the biaxial phase method and the phase translation method based on panda polarization-maintaining fiber (PMF) with enhanced scattering points array. The experimental results show that based on a 0.25 nm scanning range laser, this scheme can achieve high-precision temperature measurement (0.002 °C at 51 m) with a range of 21 °C, and its temperature measurement/laser scanning range ratio is 3 times higher than the reported schemes. This research provides valuable reference for the development of cost-effective and wide range distributed temperature measurement systems based on OFDR.