Improving the accuracy of BOFDA sensors by suppressing the secondary interaction artifacts

In this paper, we propose and demonstrate a novel method to suppress the secondary interaction artifacts affecting Brillouin Optical Frequency Domain Analysis (BOFDA) sensors. These artifacts, produced by the sidebands of the acoustic wave involved in the stimulated Brillouin scattering process, add two extra components in the baseband transfer function (TF) of the fiber under test (FUT), giving rise to systematic errors in the temperature/strain profile reconstruction. The proposed method is based on an approximate measurement of the spurious term affecting the BOFDA measurements, and its subsequent subtraction from the acquired data. The accuracy of the method is first verified numerically, and then through a number of experiments carried out over properly prepared FUTs.