Design and implementation of a mobile optical ground station for air-to-ground FSOC-Links

We present QuBUS, a mobile optical ground station designed for free-space optical communication (FSOC) and quantum key distribution (QKD). Built into a transportable lab container, QuBUS includes key subsystems such as an optical antenna with uplink lasers, a freeform telescope, acquisition and tracking hardware, relay optics, and an adaptive optics system for single-mode fiber coupling. The station is being prepared for an air-to-ground quantum communication experiment involving an aircraft-based transmitter. Initial 7-km horizontal link tests validate core functionalities, demonstrating QuBUS's potential as a compact and deployable platform for future secure quantum communication networks.