Inhomogeneous acoustic grating model for stimulated Brillouin scattering

Abstract

Stimulated Brillouin scattering (SBS) is well recognized as being useful in quantum information processing, optical fiber sensing, and LIDAR remote sensing. Here an inhomogeneous acoustic grating model based on coupled wave and dielectric grating theories is established to analyze the SBS process in water. The acoustic grating modulation process was theoretically analyzed based on the proposed model. The results show that variations of the Stokes peak intensity, frequency shift, and linewidth of SBS in water depend on the cosinusoidal refractive index modulation and periodic modulation of the acoustic grating. To verify the theoretical simulation results, an experimental system was designed to measure the SBS process in seawater with different temperatures and salinities. Theoretical results show coincidence with experimental values in the variation trend, and the numerical difference is about 10 MHz per degree Celsius or one thousandth of salinity. This work is essential to future applications of SBS in quantum communication, fiber sensing, and LIDAR technology.