6G quantum-classical signal convergence communication architecture with coordinated key management

With 5G networks enabling high-speed, low-latency communication, future 6G and quantum communications will require even higher data rates and enhanced security. Integrating quantum-safe technologies with classical systems through cofiber transmission enables the reuse of existing fiber infrastructure via multiplexing—reducing deployment costs and avoiding redundant construction. This approach offers a sustainable and environmentally friendly pathway for network evolution, positioning it as a key breakthrough in the development of secure 6G architecture.By leveraging Dense Wavelength Division Multiplexing (DWDM) over Optical Transport Networks (OTN), the system establishes an efficient bidirectional coordination framework between quantum and classical channels. The architecture incorporates multi-stage amplification, dispersion compensation, and an advanced optical-domain processing mechanism based on a "split-amplifycombine" scheme for quantum pulses. These features preserve signal integrity for both quantum and classical data while mitigating nonlinear effects. Additionally, the design includes a dual-mode key management system that meets the stringent requirements of 6G for high-speed responsiveness and large-scale concurrent quantum key distribution (QKD) through the dynamic coordination of real-time key generation and pre-stored keys. Crucially, the study analyzes Raman scattering noise in co-fiber transmission and reveals the distinct impacts of forward and backward Raman scattering on communication performance. Simulation results demonstrate that backward Raman scattering causes significantly greater degradation in secure key rate (SKR) and quantum bit error rate (QBER) than forward Raman scattering as transmission distance increases. Notably, forward Raman scattering yields better quantum communication performance metrics under ultra-long-distance transmission conditions.