Influence of optical mode polarization state on the Brillouin gain spectrum in optical microfibers

Abstract

During the stimulated Brillouin scattering (SBS) process, when the two H E 11 modes in the pump light and scattered light have different polarization states, between which is an angle θ , the Brillouin gain spectrum characteristics in a microfiber are studied in detail. The difference of θ directly changes the generated optical force distribution. When 0 ≤ θ ≤ π / 2 , for the T R 0 n acoustic mode in forward SBS and the L 0 n acoustic mode in backward SBS, the corresponding Brillouin gain values have a clear cosine-like functional relationship with θ . Considering the change of optical force, the T R 0 n and L 0 n acoustic modes with symmetrical displacement distributions of center circles are the key features to realize the change of gain with θ . The characteristics of gain value with θ may provide interesting theoretical enlightenment for Brillouin applications involving angles, such as Brillouin sensors and acousto-optic modulators.