New approach promising for free-space optical communication capacity expansion

https://www.laserfocusworld.com/science-research/article/14277850/new-approach-promising-for-freespace-optical-communication-capacity-expansion

"spatially multiplexed multi-vortex geometric beams... high-dimensional information carriers... free-space optical communication... three independent DoFs... central OAM, sub-beam OAM, and coherent-state phase... spatial modes in ray-wave duality state... wave-like and ray-like... beam-quality space of tri-DoF MVGB set densely packed... consistent propagation behavior that it possesses a high divergence degeneracy—this is the ability for dozens of different modes to share the same beam divergence"

Related: Mathematical calculations show that quantum communication across interstellar space should be possible

https://phys.org/news/2022-07-mathematical-quantum-interstellar-space.html