Limited-size aperture effects in an orbital-angular-momentum-multiplexed free-space optical data link between a ground station and a retro-reflecting UAV

In this letter, we experimentally explore the limited-size aperture effects in an orbital-angular-momentum (OAM)-multiplexed free-space optical (FSO) data link for aerial platforms. 200-Gbit/s data transmission is demonstrated between a ground transmitter and a ground receiver via a flying, retro-reflecting unmanned-aerial-vehicle (UAV) over 100-m round-trip distance by multiplexing two OAM beams. Our results indicate that when the receiver aperture size is limited, both power loss and channel crosstalk would increase. With a receiver aperture diameter of >5 cm, bit error rate (BER) mostly below 3.8 × 10−3 has been achieved for both channels