Full-range acoustic modulator based on magnetically-driven phononic crystal

Abstract This paper proposes a solid–liquid phononic crystal-based acoustic modulator which can be effectively controlled by an external magnetic field. This design is particularly well-suited for acoustic communication systems. The design consists of a square lattice of steel cylinders embedded in water as the substrate. By selectively removing specific rods, a symmetric Mach–Zehnder interferometer (MZI) is formed. The ferromagnetic material Terfenol-D is inserted into the sensing (upper) arm of the MZI as an inclusion. Applying magnetic fields of varying intensities alters the Young’s modulus of the ferromagnetic material. This change in elastic modulus induces a phase difference in the output of the modulator. The proposed modulator achieves a complete range of transmission from minimum (0%) to maximum (100%). Additionally, a high extinction ratio of 28.09 dB is reported, highlighting the excellent performance of the proposed structure.