Pulse shapes effects on backscattering Brillouin gain for distributed fiber sensing

Abstract

Distributed fiber sensing based on Brillouin gain scattering (BGS) principle is a useful way to develop devices capable to measure temperature and/or strain in optical fibers. In these distributed sensors, spatial resolution is a topic of special interest in the distributed fiber sensing field. The influence of the probe-pulse shape in the interaction between the pulsed light and the continuous wave laser in a pump-probe system. This study has the purpose of improving the spatial resolution of the measurement without losing stability in the BGS is presented. Also it is showed how the backscattering Brillouin gain is affected by inducing variations on the final value of the BGS intensity. Theoretical analysis of the probe pulse in the Brillouin shift and intensity values using triangular, sinusoidal and saw tooth shapes around the phonon lifetime (~10ns) are presented; and also considerations and conclusions are explained.