Wavelength-multiplexed decoy-state quantum key distribution with advantage distillation
Phys. Rev. Applied 25, 024018 – Published 5 February, 2026
DOI: https://doi.org/10.1103/r21k-mf9b
Abstract
Quantum key distribution (QKD) can distribute secret keys between two parties over a long distance. In practical applications, the demand for multiplexing QKD and conventional data communication through wavelength-division multiplexing (WDM) in the same fiber is increasing. However, the in-band noise that is difficult to filter out through experimental methods has become a key factor limiting the performance of WDM-QKD systems. In this work, we establish a practical decoy-state WDM-QKD model with advantage distillation (AD). We theoretically investigate the enhancement of AD technology on WDM-QKD systems and experimentally verify it. When the classical launch power is fixed at 8.6 dBm, the transmission distance can be extended by 80.3 km. When the classical received power is fixed at dBm, the tolerable classical launch power can be extended by 5.4 dBm. In the experiment, we obtained positive key rates at the optimal block lengths of 2 and 3, respectively. Our results demonstrate the enormous potential of AD in WDM-QKD applications, providing a way for reducing the impact of noise on practical WDM-QKD systems.
