Ultra-Sparse Aperiodic Silicon Optical Phased Array Using High-Performance Thermo-Optic Phase Shifter

Abstract

Integrated optical phased array (OPA) is evolving into a transformational technology for LiDAR and free-space optical communication systems due to its distinctive qualities of compact size, rapid scanning, and low cost. When the integrated OPA is utilized for long-range vehicle LiDAR (300 m range), a large emission aperture (mm-cm length) is required. However, a large aperture typically necessitates thousands of phase-controlled emitters and consumes tens of watts when utilizing traditional thermo-optic phase shifters. Here, an easy-to-understand theory is proposed and an ultra-sparse aperiodic OPA is experimentally demonstrated with a large aperture (6 mm (Formula presented.) 5 mm) using just 120 phase-controlled emitters. In the azimuthal ((Formula presented.)) direction, high resolvable points of (Formula presented.) 1300 have attained within a field of view (FOV) beam steering range of (Formula presented.). The consumed electric power is only 0.47 W thanks to the ultra-sparse aperiodic spacing ((Formula presented.) 50 (Formula presented.) average pitch) and the high-performance optical phase shifters. The fabrication-robust thermo-optic phase shifter achieved high performance in all relevant aspects including power consumption (3.1 mW/ (Formula presented.)), driving voltage (1.1 V for 2 (Formula presented.)), insertion loss (0.6 dB), modulation bandwidth (34 kHz), and footprint (42 (Formula presented.) 42 (Formula presented.)), acting as an ideal phase tuning component in large-scale photonic integrated circuits.