Advances of Optical Time Domain Brillouin Distributed Fiber Dynamic Strain Sensing Technology

Brillouin distributed fiber sensing technology can realize distributed, long-distance, high precision temperature, or strain sensing and has a wide range of applications in large-scale infrastructure security monitoring. Traditional Brillouin optical time domain analysis and reflectometry (BOTDA/R) must measure Brillouin's gain spectrum by sweeping frequency to obtain Brillouin's frequency shift. The measurement process is time-consuming, and it is difficult to measure the dynamic strain. To solve this problem, researchers have proposed various technical schemes and made significant progress. This paper summarizes the recent progress of the time-domain Brillouin optical distributed fiber dynamic strain sensing system, including the BOTDA/R dynamic sensing system based on the slope-assisted method as well as the frequency-agile, optical chirp chain, and optical frequency comb techniques.