Wide-steering-angle high-resolution optical phased array

Optical phased array(OPA) technology is considered a promising solution for solid-state beam steering to supersede the traditional mechanical beam steering. As a key component of the LIDAR system for long-range detection,OPAs featuring a wide steering angle and high resolution without beam aliasing are highly desired. However, a wide steering range requires a waveguide pitch less than half of the wavelength, which is easily subjected to cross talk. Besides, high resolution requires a large aperture, and it is normally achieved by a high count number of waveguides, which complicates the control system. To solve the mentioned issues, we design two highperformance 128-channel OPAs fabricated on a multilayered Si N-on-SOI platform. Attributed to the nonuniform antenna pitch, only 128 waveguides are used to achieve a 4 mm wide aperture. Besides, by virtue of innovative dual-level silicon nitride(Si3N4) waveguide grating antennas, the fishbone antenna OPA achieves a 100°× 19.4°field of view(FOV) with divergence of 0.021°× 0.029°, and the chain antenna OPA realizes a 140°× 19.23° FOV with divergence of 0.021°× 0.1°. To our best knowledge, 140° is the widest lateral steering range in twodimensional OPA, and 0.029° is the smallest longitudinal divergence. Finally, we embed the OPA into a frequency-modulated continuous-wave system to achieve 100 m distance measurement. The reflected signal from100 m distance is well detected with 26 d Bm input transmitter power, which proves that OPA serves as a promising candidate for transceiving optical signal in a LIDAR system.