Approach to tuning phase for periodical subwavelength grating based on Sb₂Se₃-incorporated silicon metalines

Relying on periodic alignment, dense integration and sensitive optical properties, silicon waveguide with subwavelength grating (SWG) plays an important role in area of micro-nano integrated optics. Currently, diffractive deep neural networks for passive grating component are not reconfigurable, which means their function has been fixed once fabricated. As Sb₂Se₃ material has the advantage of post-design programmability, we propose a scheme that fills Sb₂Se₃ material into the slot of the periodic SWG structure to obtain the programmable phase-change. By changing the refractive index of phase-change material (PCM) and slot structural parameters, the impact of phase-change on diffractive function are obtained, which makes the characterization of components performance reconfigurable. By using the finite-difference time-domain (FDTD) method, phase-changing are more sensitive to slot length than slot width. With the change of the refractive index, the phase can be tuned from 0 to 360° with the slot length 2.5μm, width 220nm of Sb₂Se₃. Thanks to the programmable property of silicon metalines, our proposed design has broad potentials for applications in sophisticated phase management, photonic convolution neural networks, high-speed optical communications, distributed feedback grating filters, waveguide antennas, lens modal confinement, etc.