An accurate high-resolution technique for distributed sensing based on frequency-domain Brillouin scattering

A novel high-resolution temperature/strain profile reconstruction approach, based on frequency-domain stimulated Brillouin scattering (SBS) measurements in single-mode optical fibers, is proposed and experimentally demonstrated. The proposed technique is based on an accurate modeling of the SBS interaction in the frequency domain, where even the modulation of the acoustic wave involved in the scattering process is taken into account. The reconstruction algorithm determines the unknown profile by minimizing a cost function representing the error between the measured and the model data. Experimental results show that the proposed technique allows accurate temperature/strain profile reconstructions, even when dealing with modulation frequencies rising above the natural Brillouin gain linewidth. This permits us to achieve a spatial resolution below 1 m.