Simulation of an ultrahigh capacity free space optical (FSO) communication system incorporating hybrid WDM-CPDM techniques under disturbed weather

Circular polarization division multiplexing (CPDM) is a pioneering technology that has superiority over linear polarization division multiplexing (LPDM) due to the absence of polarization axis alignment synchronization at the receiver and because it distributes the scattered light evenly. In this work, a wavelength division multiplexed (WDM) 2 x 320 Gbps free space optical (FSO) system has been presented by incorporating CPDM, 256-quadrature amplitude modulation (256-QAM), and digital signal processing (DSP). Moreover, matched filters are employed due to their anti-jamming and noise-cancelation properties. For the investigation of the proposed system at varied FSO ranges in terms of bit error rate (BER) under different weather disturbances, we have considered clear weather, heavy rain, heavy fog, and heavy dust. Results revealed that the proposed system can withstand very high power levels as high as 100 dBm and can cover 38 km under clear weather, 5 km under heavy rain, 3 km under heavy fog, and 400 m under heavy dust at 10(-3) BER.