Design and Simulation of a Hybrid Optical Antenna on Engineered Silicon on Insulator

Abstract

Microwave photonics has emerged as a promising technology for smart and efficient microwave and photonic networks. Smart antennas together with their counterpart photonic devices are crucial for the realization of microwave photonic systems. In this work, novel design of a hybrid optical antenna containing coupling waveguide, photodetector and an engineered patch antenna is proposed to realize a microwave photonic system. The detailed analysis of the whole hybrid device is presented. An efficient coupling of optical modulated signal on this hybrid chip (antenna) with ultra-low transmission losses at narrow-core waveguide is achieved to obtain high performance photodetection and optimized radiation from an engineered antenna. Firstly, an efficient broadband in-coupler on engineered Siliconon-Insulator (SOI) for strong coupling of optical modulated signal and hybrid chip is designed and analyzed using grating based photonic coupler approach. High-index contrast grating (HCG) is one of the innovative form of grating which is used for this coupling scheme. The formation of high-index contrast grating (HCG) by the periodic layers of silicon and air on top layer of silicon of SOI allows a tight interaction between the guided mode and the grating thereby efficient coupling is achieved by optimizing the different grating parameters i.e. grating thickness (tg), grating period (and#923;) and duty cycle (C)over a broad range of wavelength (and#955;). Further, a new plan for ultra low-loss transmission of this efficient coupled light through HCG assisted narrow-core optical waveguide structure is proposed. The analysis of transmission of guided modes within narrow-core waveguide is done by Finite-difference-time-domain (FDTD) numerical method. An ultra low transmission loss through proposed design is achieved in the narrow-core hollow waveguide due to unique polarization and angular dependence of the HCG reflection spectrum. Finally, HCG assisted hollow waveguide considerably reduces the dispersion and nonlinear effects