Enhanced Atmospheric Turbulence Resiliency With Successive Interference Cancellation DSP in Mode Division Multiplexing Free-Space Optical Links

• DOI: 10.1109/jlt.2022.3209092
• Publication Date: 2022-09-30T19:48:29Z
• Authors: Yiming Li; Zhaozhong Chen; Zhouyi Hu; David M. Benton; Abdallah A. I. Ali; Mohammed Patel; Martin P. J. Lavery; Andrew D. Ellis
• Keywords: Signal Processing (eess.SP); 0103 physical sciences; FOS: Electrical engineering, electronic engineering, information engineering; FOS: Physical sciences; Electrical Engineering and Systems Science - Signal Processing; 01 natural sciences; Physics - Optics; Optics (physics.optics)

We experimentally demonstrate the enhanced atmospheric turbulence resiliency in a 137.8 Gbit/s/mode mode-division multiplexing free-space optical communication link through the application of a successive interference cancellation digital signal processing algorithm. The turbulence resiliency is further enhanced through redundant receive channels in the mode-division multiplexing link. The proof of concept demonstration is performed using commercially available mode-selective photonic lanterns, a commercial transponder, and a spatial light modulator based turbulence emulator. In this link, 5 spatial modes with each mode carrying 34.46 GBaud dual-polarization quadrature phase shift keying signals are successfully transmitted with an average bit error rate lower than the hard-decision forward error correction limit. As a result, we achieved a record-high mode- and polarization-division multiplexing channel number of 10, a record-high line rate of 689.23 Gbit/s, and a record-high net spectral efficiency of 13.9 bit/s/Hz in emulated turbulent links in a mode-division multiplexing free-space optical system.