High-Pass Filtering for Accuracy Enhancement in Dark-Pulse Brillouin Optical Time Domain Analysis

In this letter, we demonstrate a simple technique aimed to enhance the accuracy in dark-pulse Brillouin optical time-domain analysis (BOTDA) sensors. Modeling the stimulated Brillouin scattering in the frequency domain, we show that the degrading features related to the pump background can be removed by applying a high-pass filter to the raw data, at the cost of some degradation of the signal-to-noise ratio. A numerical analysis, as well as experimental tests carried out at 20-cm spatial resolution, validate the proposed technique.