Beyond 50 Gbps 100 m visible light laser communication single-transmitter-multi-receiver system utilizing triple branch neural network

In the forthcoming 6 G communication era, traditional electromagnetic spectra are increasingly inadequate to meet growing demands. Visible Light Communication (VLC) technology offers a promising high-speed solution due to its flexible deployment and cost-effectiveness. However, long-distance VLC applications are challenged by factors such as atmospheric turbulence and nonlinear distortions. To address these issues, laser diodes (LDs) with high modulation bandwidth and reliable, easily deployable channel estimation techniques are essential. This paper presents what we believe to be a novel visible light laser communication (VLLC) single-transmitter-multi-receiver system utilizing red, green, and blue (RGB) laser diodes. We successfully achieved a 100-meter free-space transmission using time-domain hybrid huffman coding (TDHHC) combined with a triple branch neural network (TBNN) technique. The system attained transmission rates of 51.05 Gbps in turbulence-free conditions and 46.5 Gbps under strong turbulence, while maintaining a bit error rate (BER) below the stringent 3.8E-3 threshold specified by the 7% hard decision forward error correction (HD-FEC) standard. To our knowledge, this represents the highest data rate recorded in a 100 m tri-color VLLC system.