Speeds of 20 Gbps at distances of 20km without fiber cable seem impossible but this is promised by project taara or google fsco tech. This is achieved by sending a concentrated beam of light between through transceiver who have a direct LoS.

Free-space optical communication (FSOC) uses tightly focused laser beams to quickly send data over long distances. This makes the signal strong but also requires precise alignment between devices, especially in changing environments. Convention beam steering methods such as MEMS mirrors or voice-coil actuators rely on moving parts, which can make systems more complex, costly, and less reliable over time.

New advances to know- photonic chip advances, optical phased arrays