Cooperative FSO and mmWave System for Reliable 200G Wireless Transmission

The use of free-space optics (FSO) for ultra-high-speed communications has been recently standing out as a promising alternative for fiber/wireless-based scenarios. However, FSO communications still suffer from variations in the received optical power due to atmospheric turbulence and weather instability, which limits its use in reliability-driven applications. To explore the full potential of FSO and maintain communications reliability, hybrid FSO and radio-frequency systems can be employed to leverage the strengths of the two technologies. In this letter, we demonstrate a 3m hybrid FSO and millimeter-wave system for 200G stable wireless transmission. Resorting to time-adaptive probabilistic constellation shaping and a cross-domain entropy loading scheme, we are able to compensate for up to 15% (30Gbps) of data-rate reduction in the FSO link. Comparing with FSO-only transmission, we demonstrate a cumulative capacity gain of over 150Gbps after 40 offline measurement iterations.