Magnetically switchable 1×3 demultiplexer based on Terfenol-D-integrated phononic crystal ring resonators

This research unveils a magnetically adjustable 1 × 3 demultiplexer architecture engineered within a two-dimensional solid-state phononic crystal. The core design leverages ring resonator cavities integrated with magnetostrictive Terfenol-D cylinders, capitalizing on their field-dependent Young's modulus to achieve dynamic resonance control in the GHz frequency regime. The phononic crystal platform is designed from silicon, incorporating a square lattice of cylindrical tungsten scatters to establish a complete phononic band gap. A central bus waveguide couples acoustically to three distinct ring resonators, each further coupled to individual drop waveguides for channel isolation. Notably, each ring resonator features a strategically positioned Terfenol-D cylinder adjacent to its central cavity. Magnetically tunable switching of the elastic demultiplexer outputs is achieved by dynamically modulating the Young's modulus of Terfenol-D cylinders embedded within the ring resonators via an external magnetic field. This field-induced magnetoelastic effect enables precise resonance control. Application of three distinct magnetic field intensities selectively sets the Young's modulus of the Terfenol-D to three discrete values (39 GPa, 49 GPa, and 60 GPa). Each modulus value configures its corresponding ring resonator to resonate at a unique frequency (5.5788 GHz, 5.5918 GHz, 5.6003 GHz), facilitating discrete high-transmission peaks with narrow bandwidth at the designated output channels. Key performance metrics include an average quality factor (Q-factor) of 7105, indicating high spectral selectivity; minimal average insertion loss of 1.01 dB, signifying efficient signal transmission; and average crosstalk of -33.71 dB, highlighting effective channel isolation. Its innovative use of magnetostrictive materials and external field modulation opens new avenues for reconfigurable acoustic systems and networks.