1. Introduction
An optical phased array (OPA), which enables high-speed non-mechanical beam-steering using a compact semiconductor chip, is drawing increasing interest for various sensing applications, such as light detection and ranging (LiDAR) and optical coherence tomography (OCT). With the recent advancement of photonic integration technologies, large-scale OPAs with hundreds of phase shifters operating at 1550-nm wavelength range have been demonstrated on Si and platforms [1]–[4]. For many sensing applications, however, operation at wavelength range (i.e., 905-nm or 1050-nm) has several advantages, such as smaller water absorption [5], [6], higher spatial resolution due to the shorter wavelength, and the feasibility of using cost-effective silicon photo detectors [7]. While OPAs working at band have been developed on platforms [8], [9], the number of phase shifters was limited to 16 or fewer.