Strain event detection using a double-pulse technique of a Brillouin scattering-based distributed optical fiber sensor.

Stimulated Brillouin scattering in optical fibers can be used to measure strain or temperature in a distributed manner. Brillouin optical time domain analysis (BOTDA) is the most common sensor system based on the Brillouin scattering. To improve the spatial resolution of these measurements, shorter pulses must be used, resulting in reduced signal powers causing a decrease of the dynamic range. In this paper, a doublepulse technique was proposed to enhance the spatial resolution of BOTDA. Experimental results showed that the ability to resolve two adjacent events could be enhanced, about twice, by using a double-pulsed pump light without decreases in the dynamic range.