Compact and Efficient Transverse Spliced Waveguide Grating Antenna for Integrated Optical Phased Array

Abstract

Waveguide grating antenna with compact size and high diffraction efficiency remains a significant challenge in beam steering applications for integrated Optical Phased Arrays (OPA). Traditional waveguide grating antennas have large footprints, limiting antenna arrays' density. High diffraction efficiency is essential for effective signal transmission, making it a crucial aspect of antenna design. Optical antennas need higher diffraction efficiency, compact size, and broader field of view to achieve this. The proposed work aims to design a single-etch grating antenna on a silicon-on-insulator (SOI) platform that emits light off-chip. The methodology combines the initial grating antenna designed using Finite-difference time-domain (FDTD) simulations and optimizes it with a genetic algorithm. The proposed design uses a transverse spliced grating, Bragg reflectors, and bottom reflector to achieve an impressive upward diffraction efficiency of nearly 88% operating in C -band centered at 1550 nm. The size of the proposed antenna is 2.8 μm and offers a wide far-field beam width of 38 ° x 136 °. This work enables new advancements in integrated waveguide grating antenna development, with potential applications in free-space optical interconnects and on-chip optical phased arrays.