This phenomenon, known as the acousto-optic (AO) diffraction, has led to a variety of optical devices that perform spatial, temporal, and spectral modulations of light. These devices have been used in optical systems for light-beam control and signal-processing applications. Our group, established at the Institute of Materials Science, Department of Applied Physics, of. Follow the acousto-optic devices expert Smart to enter the world of Distributed Acoustic Sensing (DAS) and Distributed Fiber Optic Sensing (DFOS) in Acoustic/Optical Fibers. This groundbreaking technology converts a single fiber optic cable into a powerful monitoring tool capable of “hearing”. The ideal development direction of the fiber-optic acoustic sensor (FOAS) is toward broadband, a high sensitivity and a large dynamic range.