Common-path optical terminals for Gbps full-duplex FSO communications between a ground and UAVs

We present common path-based optical terminals designed for full-duplex free-space optical (FSO) communications to apply for unmanned aerial vehicles (UAVs) to ground communication. The FSO terminals were carefully designed by taking into account flight issues of UAVs. Simple and compact FSO terminals were produced by integrating optical components for transmitting and receiving data-carrying beams and a beacon beam to track the other party FSO terminal. Preliminary experiment that was carried out with the FSO terminals installed at fixed position showed a 1.25-Gbps full-duplex error-free communication link for a bit error rate of ~10−12 over 50 m.