High-capacity free-space optical communication using quadruplex cylindrical vector beam multiplexing: a 3.2km field experiment

In this work, we demonstrated an 80Gbit/s high-speed FSO communication system using four coaxially multiplexed CVBs over a 3.2km real atmospheric link. Each beam carried a 20Gbit/s on–off keying (OOK) signal. Under moderate atmospheric turbulence conditions, with an average turbulence intensity of approximately C2n ≈ 1×10-14, all four channels achieved bit error rates (BER) below the HD-FEC threshold of 3.8×10-3 in approximately 50% of the communication trials, demonstrating the potential for reliable demodulation in practical turbulent environments. This work demonstrates the feasibility of multi-dimensional spatial multiplexing using CVBs and offers a foundation for next -generation free-space laser communication.