We present the structures and performances of silicon-photonics-based optical phased-arrays (OPAs) to achieve wide beam-forming angles for LiDAR applications. Beam-forming and steering are experimentally
demonstrated with 1x16 OPAs in which power splitters, phase shifters, and radiators are integrated on a silicon photonics platform. For wide transversal steering over 45degrees, two radiator types are examined, the
grating- and photonic crystal-based structures. We will compare the detailed performances and tradeoffs for such structures.