Sustained 103.125 Gbps simultaneously bidirectional FSO communication in a 1395-m airship-to-ground link over 216 min

Free-space optical (FSO) communication offers promising advantages not only for satellite links but also for low-altitude floating platforms (LAFPs) such as airships. However, unlike satellites, airships are subject to random attitude perturbations during station-keeping, posing significant challenges to FSO link acquisition and stability, while atmospheric turbulence further degrades link availability. In an experimental demonstration conducted over the coastal area in Ningbo, a simultaneous bidirectional 103.125-Gbps link was maintained over 216 min between an airship at 420-m altitude and a ground station over a 1395-m slant range. Using dual-polarization quadrature phase shift keying (DP-QPSK) modulation, the system achieved a tracking accuracy of 10 µrad under airship motion while sustaining a bit-error rate (BER) between 1E-8 and 1E-11. To the best of our knowledge, this work represents the first demonstration of simultaneous bidirectional, 100 Gbps-class, hour-long uninterrupted FSO communication for an airship-to-ground link, marking a notable milestone in FSO technology applications.