Brillouin spectral deconvolution method for centimeter spatial resolution and high-accuracy strain measurement in Brillouin sensors

Combining a dc and a short pulse (approximately 1 ns) as the probe beam in the pump-probe configuration of Brillouin-based distributed sensors allows us to represent the Brillouin spectrum as a top Lorentzian-like portion and a bottom Gaussian-like portion. Because of the interaction of these two parts, the Lorentzian-like portion carries spatial information that can be extracted within centimeter spatial resolution. Using this information, we develop a spectrum deconvolution method, which considers the location correlation of the strain distribution, to find the number of Brillouin peaks and their frequencies in the top Lorentzian-like portion and hence achieve accurate strain information. An optimum level of dc to pulse power for the best signal and position detection capability is discussed.