Temperature sensing based on forward stimulated Brillouin scattering using high-order optical modes in few-mode fibers

This paper proposes and investigates a temperature sensing approach using forward stimulated Brillouin scattering (FSBS) activated by high-order optical modes (HOMs) in four-mode fibers. Experimental and simulation results demonstrate that high-order guided acoustic modes associated with HOMs are significantly enhanced in few-mode fibers (FMFs) compared to single-mode fibers. The increased amplitude of these guided acoustic modes, along with their larger temperature sensitivity, provides an improved temperature resolution for FSBS-based temperature sensing in FMFs. This research not only contributes to a better understanding of FSBS in FMFs but also opens new avenues for developing high-performance temperature sensors in FMFs using a sub-GHz frequency scan for a wide range of applications.