Silicon Optical Phased Array Hybrid Integrated with III-V Laser for Grating Lobe-Free Beam Steering

A silicon photonics-based optical phased array (OPA) is promising for realizing solid-state and miniature beam steering. In our work, a 1 x 16 silicon optical phased array (OPA) hybrid integrated with a III-V laser is proposed and demonstrated. The III-V laser chip is vertically coupled with a silicon OPA chip based on a chirped grating coupler with a large bandwidth. The coupling efficiency reaches up to 90% through utilizing the metal reflector underneath the silicon oxide layer. The one-dimensional antenna array comprising silicon waveguides with half-wavelength spacing enables beam steering with none high-order grating lobes in a 180 degrees field of view. The measured beam steering angle of the hybrid integrated OPA chip is +/- 25 degrees, without grating lobes, and the suppression ratio of the side-lobes is larger than 9.8 dB with phase calibration.