Solid-state two-dimensional scanning free-space optical communication system

Abstract

Free-space optical communication has emerged as a promising solution for high-capacity wireless transmission due to its high carrier frequency, narrow beam divergence, and strong anti-interception capability. However, conventional FSOC systems commonly rely on mechanically driven beam steering structures, which suffer from large inertia, vibration sensitivity, and limited scalability for compact platforms. To address these limitations, this paper presents a solid-state two-dimensional scanning FSOC system based on the hybrid integration of a silicon optical phased array and a liquid crystal on silicon (LCoS) modulator. The proposed architecture eliminates mechanically moving components while enabling two-dimensional beam steering and gigabit-level optical transmission. In the transmitter, the silicon-based OPA performs one-dimensional beam steering, while the LCoS device provides orthogonal scanning capability. The receiver adopts an LCoS-assisted feedback architecture with centroid extraction for angular tracking and fiber coupling. Experimental validation was conducted over a free-space channel. The proposed system successfully demonstrated on-off keying transmission at data rates up to 1.1 Gbps. The measured eye diagram at 1.1 Gbps achieved a Q-factor of 4.82 and timing jitter of 42.93ps, verifying the feasibility of high-speed communication using a solid-state beam steering architecture. The proposed system provides a promising pathway toward lightweight, low-power, and vibration-insensitive optical communication terminals for future satellite, airborne, and long-distance communication applications.