Dynamic Distributed Fiber Optic Strain Sensing on Movement Detection

A real-time dynamic Brillouin optical time domain reflectometry (BOTDR)-based system is introduced by using small gain stimulated Brillouin scattering with fast data managing and saving method. The system achieves 2-cm read-out interval, 2-m spatial resolution, and about 7-mu epsilon accuracy with about 7 Hz or even faster with 23 Hz continuous monitoring. A movement response on a polymer mat made pavement was successfully monitored by the proposed system. For example, the pace distance at each walking step was detected to be 0.62 m. In addition, the minimum strain difference measured after several human loads is about 10 mu epsilon with 7-mu epsilon uncertainty and 3-mu epsilon repeatability, indicating the possibility of real-time strain monitoring and the movement or trajectory detection by distributed fiber optic strain sensing.