High-Directionality Silicon Nitride Antenna Based on Distributed Bragg Reflector for Optical Phased Array

Abstract

Optical phased arrays (OPAs) have great potential in the fields of integrated solid-state light detection and ranging. The ranging distance of an OPA can be further enlarged by improving the directionality of the grating antenna. A high-directionality silicon nitride grating antenna with a distributed Bragg reflector (DBR) is proposed. The DBR consists of a stack of silicon nitride and silicon dioxide layers, which are utilized as the bottom reflectors to further reduce downward radiation. In a simulation, the directionality of the antenna exceeded 71.6% within the wavelength range of 1420–1740 nm. Additionally, the directionality of the antenna can achieve 97.6% at 1550 nm. Compared to a grating antenna without a DBR, the directionality is improved by 1.52 dB. Moreover, the proposed silicon nitride grating antenna has a large fabrication tolerance and is compatible with CMOS fabrication techniques, showing great potential for enhancing the performance of the integrated optical phased array.