Novel On-chip True Time Delay Engine using Frozen Modes for mm-Wave Beamforming and Optical Networking

Abstract

We present a simple all-dielectric photonic waveguide structure based on Silicon-on-Insulator platform that exhibits 3rd-order degeneracy enabling frozen modes. Such degenerate propagation modes with vanishing group velocity is realized by introducing coupling among 3 neighboring Si ridge waveguides to design a stationary inflection point in the dispersion diagram, leading to the frozen mode and a true time delay device capable of 0.5 THz ultra-wide-band beamforming for millimeter wave phased arrays. For a 1 Tbit/s optical transmission system, the device is capable of data buffer or synchronization of up to 14 bits. The 600x slowing down of light compared to free space optics could be utilized for applications like biosensors and optical coherence tomography, in addition to ultra-wideband beamforming of phased arrays.