Hybrid Optical–Quantum Networks: Optimal Design and Physical-Layer Cybersecurity

The rapid advancement of quantum computing poses a fundamental threat to classical cryptographic systems, creating an urgent need for quantum-safe communication architectures at the physical layer. Most quantum communication studies to date have focused on fiber-based environments, while transitioning these systems to free-space channels remains challenging due to polarization instability, phase fluctuations, and strong line-of-sight (LOS) sensitivity. At the same time, laser and free-space optical links have typically been examined independently, without considering their interaction with quantum channels. In practice, both technologies rely on a nearly shared LOS-dependent optical infrastructure: the quantum channel provides secure key generation, and the laser link complements it with high-rate secure data transmission. This project introduces an optimal design framework that integrates a DV-QKD-based quantum and physical-layer security core with a unified hybrid optical–quantum link built on shared infrastructure

Hamad Bin Khalifa University (HBKU)