Analysis and Design of an Integrated Compact RF Driving System for PIC-Based Hybrid AOM Phase Shifters for Free Space Optical Communication

Abstract

When using Radio Frequency aboard small satellites, for high data rates, this would need large antennas, violating constraints related to size, weight, and power. As an alternative, Free Space Optical Communication (FSOC) uses laser beams, operating in the optical and infrared frequency domain, in order to transmit data through the atmosphere between satellites and ground stations. However, implementing FSOC systems on (small) satellites remains challenging. In this paper, we investigate the role of phase shifting in FSOC systems. The functionality of these phase shifters is used for modulation, beam steering using optical phased arrays, and phase stabilization of the transmit and receive beams. This is where Photonic Integrated Circuit (PIC)-based platforms could offer a solution. Their extremely compact form factor makes them ideal for space applications. Phase shifters embedded within PIC-based platforms offer a known solution by allowing dynamic manipulation of the phase of light. A specific setup, namely the use of hybrid AOMs, looks promising as other phase shifting techniques can suffer from several issues, such as being thermal sensitive, having non-linear effects and possible material degradation in the long-Term. As these devices come with their own challenges, this work identifies these shortcomings and focuses on the analysis and design of an efficient low-power miniaturized RF driving system, in combination with the design of an efficient hybrid AOM setup for phase shifting in a PIC environment.