Amadou Soumahoro^1,, Douatia Koné^{1, 2}, Aladji Kamagaté¹

Free space optics (FSO) is a promising technology, enabling high-speed data transmission despite challenging and unpredictable atmospheric conditions. However, its performance remains highly dependent on the propagation environment and the type of optical pulse used. This present work analyzes the reception performance of FSO systems employing soliton microcombs with wavelength division multiplexing (WDM) and polarization shift keying (PolSK) modulation across various pulse profiles. The study focuses on comparison of the impact of pulse shaping namely Gaussian, Sech, Super-Gaussian, and Lorentzian profiles on key reception parameters such as Bit Error Rate (BER), received power, Q-factor, and eye diagram opening, under realistic atmospheric conditions including turbulence () and pointing errors. Results reveal that the Sech-shaped microcombs consistently offer superior performance, with larger eye openings (± 2.5 A), higher received power (28.5 dBm), Q-factors exceeding 12.5, and BERs below 10⁻⁹ for a total generated bandwidth of ~12.5 THz, even under non-ideal alignment. The Gaussian profile follows closely, while Lorentzian and Super-Gaussian pulses exhibit significant performance degradation. The analysis also shows that optimizing receiver aperture diameter (40–60 cm) and beam divergence (0.25 mrad) enhances resilience to turbulence and alignment jitter. This study highlights the importance of pulse-profile design in soliton-based multi-wavelength FSO systems and provides actionable insights for optimizing waveform generation in spectrally efficient optical wireless links.

Optical Free Space, reception performance, soliton, microcombs, pointing errors, pulse profiles