Phase-combining unit for aliasing suppression in an optical phased array.

Integrated optical phased array (OPA) devices have been widely studied as a solution for solid-state light detection and ranging technology in the autonomous driving application. In this work, a phase-combining unit (PCU) is proposed and studied. With a given number (N) of phase shifters, instead of the general N (phase shifters) to N (emitters) control, the PCU can enable an N to 2N-1 control, which efficiently suppresses the aliasing effect. The theoretical analysis, numerical simulation, and experimental proof-of-concept have been completed in this work. The results show that a maximum suppression of 92.54% can be achieved for the grating lobes in simulation, and an average 53.76% is tested for one grating lobe in the experiment. In conclusion, the PCU can be used as a universal aliasing suppression unit on many types of integrated OPA devices.