A 100-Gb/s hybrid PDM-DWDM system for simultaneous bidirectional LEO-to-LEO inter-satellite optical communication

Optical inter-satellite links (ISLs) have emerged as a key enabling technology for next-generation satellite communication networks due to their advantages over traditional radio-frequency (RF) based ISLs. However, practical high-capacity links must combine bidirectional operation, compact terminals and resilience to dynamic pointing errors. We present a unified design and performance analysis of a 100-Gb/s aggregate hybrid polarization division multiplexing (PDM) and dense wavelength division multiplexing (DWDM) bidirectional low-earth orbit (LEO) ISL. The design integrates a compact 10 cm common aperture on each satellite, dedicated forward and return wavelengths around the 1550 nm window, quantified local transmitter-receiver isolation and an optically pre-amplified receiver model. The system performance is evaluated using a detailed link budget and Monte Carlo framework that incorporates two-dimensional Gaussian pointing jitter together with varying transmitter power, link ranges, Mach–Zehnder modulator extinction ratio, polarization extinction ratio and optical aperture efficiency over \:10⁵ independent realizations. Performance is quantified through signal-to-noise ratio (SNR), cumulative distribution functions (CDFs), average bit-error ratio (BER) and outage probabilities. Under conservative worst-case pointing conditions, our proposed system supports simultaneous 100 Gb/s aggregate bidirectional operation over separations up to 6000 km, yielding an average BER \:≤\:2.5×\:10⁻² with \:≤\:\:2.58% SD-FEC outage at 37 dBm transmit power. These results indicate the proposed architecture’s viability for high-capacity bidirectional optical inter-satellite links using a single compact aperture per satellite, while establishing quantitative design requirements for compact LEO satellite terminals.