Integration of Quantum Key Distribution in 6G Passive WDM Optical Fronthaul Architecture

The advancement of 6G networks demands high-capacity, ultra-low latency, and secure communication infrastructure. Traditional fronthaul solutions face significant challenges in meeting these demands due to increasing data traffic, network densification, and security vulnerabilities. To address these issues, this paper proposes an innovative 6G passive Wavelength Division Multiplexing (WDM) fronthaul architecture integrated with Quantum Key Distribution (QKD). By leveraging quantum cryptographic principles, our approach ensures unbreakable security and protects network transmissions from potential cyber threats and eavesdropping attacks. The proposed architecture effectively combines high-speed optical transmission with quantum-secured key exchange, optimizing network reliability and reducing security risks. Through comprehensive simulations, we evaluate key performance factors, including secure key rate (SKR), quantum bit error rate (QBER), detector efficiency, and quantum transmission loss. Results indicate that our architecture maintains high SKR with minimal QBER, even under challenging transmission conditions, ensuring robust quantum-secured communication. Additionally, the passive nature of WDM significantly reduces power consumption and maintenance costs, improving network sustainability. This research establishes a practical pathway for integrating quantum security into next-generation optical fronthaul networks, enabling highly secure, scalable, and efficient data transmission for future 6G applications, including autonomous vehicles, smart cities, and industrial IoT.