Waveguide grating antenna toward optical phase array application functioned with two polarizations

A waveguide grating antenna (WGA) is an important component in optical phased array (OPA) systems featured by all-solid-state configurations for 3D imaging. The high-performance WGAs with dual polarization, easy fabrication, high radiation efficiency, and high angular resolution are desired for OPAs. This paper presents, to our knowledge, a novel polarization-insensitive WGA design capable of supporting both TE and TM modes, featuring a critical feature size exceeding 250 nm. The designed device demonstrates that this grating antenna exhibits similar upward radiation efficiencies (∼85 % for TE and ∼80 % for TM) and radiation angles at a wavelength of 1550 nm. The experimental results show that grating antenna perturbation strength can be achieved at less than 4.8×10 −4 / μm for both polarizations. The measured beam divergences are 0.01° (TE) and 0.0101° (TM), with a wavelength scanning sensitivity of 0.123 deg/nm. The proposed polarization-insensitive WGA with high performance is compatible with the 3 μm commercial platform and an OPA system based on the designed WGA has been designed and simulated.