Abstract The advent of quantum computing necessitates the integration of post-quantum cryptography (PQC) into high-speed optical networks to safeguard against emerging threats. This study rigorously evaluates NIST-standardized PQC digital signature algorithms – CRYSTALS-Dilithium, FALCON, and SPHINCS+ – in wavelength-division multiplexing (WDM) systems, addressing the critical interplay between cryptographic robustness, file size dynamics, and optical network performance. Through comprehensive OptiSystem simulations, we analyze transmission fidelity (BER, Q-factor), power efficiency, and channel spacing impacts across single- and multi-channel WDM architectures. Key findings reveal that compact lattice-based schemes like FALCON-512 achieve high Q-factor at optimum power (−2) dBm for small files (≤45 bits), making them ideal for latency-sensitive applications such as real-time financial transactions. Conversely, large files (>200 bits) demand adaptive power allocation (−12 dBm–−10 dBm) and hybrid error correction (LDPC + FEC) when using SPHINCS + , despite its 41 kB signature overhead. Optimal channel spacing (0.8 nm for metro networks, 1.6 nm for long-haul links) balances spectral efficiency and resilience to distortions. The results underscore the necessity of context-aware cryptographic frameworks: FALCON-512 excels in low-power, high-security metro-scale deployments (50–100 km), while SPHINCS + suits archival data with high throughput tolerance. This work provides actionable insights for designing quantum-safe optical networks, harmonizing PQC standards with the evolving demands of high-capacity, low-latency infrastructure.
Hamood et al. (Thu,) studied this question.