A 4 × 210 Gbps high-speed optical wireless system in medium earth orbit (MEO) using matched filters and digital signal processing

Abstract In this work, a high-speed optical wireless system is realized to cater to the bandwidth demands of data services in inter-satellite by using 4 × 210 Gbps capacity enabled by dual-polarization (DP) 128-Quadrature amplitude modulation (QAM) at 25 GHz channel spacing and artificial intelligence (AI). For nonlinear compensation, equalization, normalization, and interference reduction, digital signal processing (DSP), and matched filters are included in the receiver. Results are analyzed by considering error vector magnitude (EVM), Q-factor, and BER at different link lengths. Moreover, two polarizations such as horizontal and vertical polarizations are investigated separately to find out optimal polarization state. Further comparison of the proposed DP-128 QAM is performed with quadrature phase-shift keying (QPSK)and results revealed that the QAM system carrying different states of polarization (SOPs) successfully covered 17,500 km at 125 Gbps and offered enhanced performance as compared to the conventional QPSK and QAM modulations due to narrow carrier spectrum (2 7 symbols).