Dual-polarized PAM-4 modulation for 100 Gbps inter-satellite optical wireless communication: performance analysis under aperture, loss, and pointing error constraints

Abstract This paper presents a dual-polarized Pulse Amplitude Modulation-4 (PAM-4) based inter-satellite optical wireless communication (IsOWC) system achieving 100 Gbps aggregate data rate using an 850 nm laser. Two orthogonally polarized beams each carry 50 Gbps, enabling spectrally efficient transmission over ranges of 8,000–20,000 km. System performance is evaluated using log(BER), EVM%, and eye diagrams across three parametric studies: receiver aperture diameter (10, 12, 15 cm), additional channel losses (5, 7, 9 dB), and laser transmission power (26, 28, 30 dBm) under pointing errors of 1–2 μrad. Results demonstrate that larger apertures and higher transmission powers significantly improve link performance, while pointing error proves a critical limiting factor at extended ranges. The proposed architecture offers a viable solution for next-generation high-throughput IsOWC systems.