Two-dimensional single-lobe Si photonic optical phased array with minimal antennas using a non-uniform large spacing array design

Abstract

We report a two-dimensional Si photonic optical phased array (OPA) optimized for a large optical aperture with a minimal number of antennas while maintaining single-lobe far field. The OPA chip has an optical aperture of ∼ 200 µ m by 150 µm comprising a 9 × 9 antenna array. The two-dimensional spacings between these antennas are much larger than the wavelength and are highly non-uniform optimized by the genetic deep learning algorithm. The phase of each antenna is independently tunable by a thermo-optical phase shifter. The experimental results validate the design and exhibit a 0.39 ∘ × 0.41 ∘ beamwidth within the 3 dB steering range of 14 ∘ × 11 ∘ limited by the numerical aperture of the far-field camera system. The method can be easily extended to a larger aperture for narrower beamwidth and wider steering range.