We demonstrate crosstalk mitigation using 4 × 4 multiple-input- multiple-output (MIMO) equalization on an orbital angular momentum (OAM) multiplexed free-space data link with heterodyne detection. Four multiplexed OAM beams, each carrying a 20 Gbit/s quadrature phase-shift keying signal, propagate through weak turbulence. The turbulence induces inter-channel crosstalk among each beam and degrades the signal performance. Experimental results demonstrate that with the assistance of MIMO processing, the signal quality and the bit-error-rate (BER) performance can be improved. The power penalty can be reduced by >4 dB at a BER of 3.8 × 10-3.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics