Sweep-free distributed Brillouin time-domain analyzer (SF-BOTDA).

A frequency-sweep-free method for distributed Brillouin sensing is proposed, having the potential for fast dynamic strain measurements. In this reported implementation of the method, multiple probe waves with carefully chosen optical frequencies simultaneously propagate in the fiber against an equal number of sequentially-launched, short pump pulses of matching frequencies, where each of pump-probe pair replaces one sweeping step in the classical BOTDA technique. Experimentally, distributed sensing is demonstrated with a spatial resolution of a few meters.