Phase Perturbation Analysis for Transient Response of Forward Brillouin Scattering in Acoustic Impedance Sensing

Forward Brillouin scattering (FBS) is a newly developed sensing mechanism in optical fiber that has garnered significant attention recently for its ability to identify substances. FBS occurs as a result of optical scattering caused by transverse resonant acoustic waves, and the lifetime of the acoustic wave and the spectral linewidth are directly linked to the acoustic reflectivity on the boundary of the optical fiber. Analyzing the transient response of FBS is essential for enhancing the performance of distributed and non-distributed optical fiber sensing based on FBS. A novel method for phase perturbation analysis is proposed to extract FBS signals from strong background interference caused by the Kerr effect. This presentation represents the first attempt to analyze the FBS properties in the construction process. The proposed theory and experimental results are consistent with and explain previously observed but unexplained phenomena, and are expected to be useful for future analysis.