Environmental impact on the spectral performance of gold-coated retroreflector in UAV-based free-space optical communication systems

This research presents an experimental and simulation-based study on the performance of a gold-coated retroreflector designed to operate in the visible to infrared (500 nm - 1600 nm) spectral range, with potential applications in free-space optical (FSO) communication and UAV-based systems. The retroreflector, with a 2 cm² integrating sphere, was tested experimentally to measure its specular reflection properties under varying conditions of bed temperature and initial beam line width. These conditions were selected to simulate typical operational and environmental stressors that a UAV or optical communication system might encounter. Experimental measurements of the specular reflection coefficient were obtained across a range of bed temperatures, simulating the thermal gradients that could be experienced in high-altitude or varying climate conditions. Additionally, different line widths were applied to assess the retroreflector’s performance under diverse optical alignment scenarios, relevant to practical deployments where beam divergence and alignment errors could degrade signal quality. The experimental data, specifically the reflective values, were subsequently employed in Optsystem simulations to evaluate the power returned from the retroreflector under different atmospheric conditions, including clear and cloudy skies, with varying rain rates. These simulations were critical in assessing the degradation of signal power due to absorption, scattering, and atmospheric turbulence, which are common challenges in FSO systems. The simulation results demonstrate how environmental factors affect the returned power, which is critical for applications in optical communication systems, UAV navigation, and tracking systems in adverse weather conditions. This study paves the way for further research into optimizing retroreflective materials and system configurations for real-world applications, including satellite communication and UAV-based systems operating in diverse meteorological environments.