Photonic Lantern-Based High Capacity Multiple-Input Multiple-Output Free-Space Optical Communications
Yiming Li, Aston University

By developing a highly-flexible digital signal processing (DSP) architecture, we successfully demonstrate record-high-performance mode-division multiplexing (MDM) multiple-input multiple-output (MIMO) coherent free-space optical (FSO) communication systems. The DSP architecture supports versatile MIMO decoding algorithms, allowing us to demonstrate a record-high channel number of 10. By employing the adaptive bit-loading algorithm, the DSP architecture demonstrated a spectral efficiency of 28.35 bit/s/Hz and a record-high transmission line rate of 1.33 Tbit/s. By employing a successive interference cancellation MIMO decoder, the system also demonstrates enhanced turbulence resiliency using the DSP-based method with a line rate of 689.23 Gbit/s. Moreover, this architecture supports asynchronous phase noise and shows Cramer-Rao Lower Bound approaching performance for channel and phase estimation. Furthermore, the architecture reduces the hardware requirements and enables the possibility to employ commercially available mode-selective photonic lanterns for MDM transmission, which is preferable for commercial applications.