Improved model on asynchronous measurement-device-independent quantum key distribution with realistic devices

In principle, the asynchronous measurement-device-independent quantum key distribution (AMDI-QKD) can surpass the key rate capacity without phase tracking and phase locking. However, practical imperfections in sources or detections would dramatically depress its performance. Here, we present an improved model on AMDI-QKD to reduce the influence of these imperfections, including intensity fluctuation, the afterpulse effect, and the dead time of detectors. Furthermore, we carry out corresponding numerical simulations. Simulation results show that, by implementing our present work, it can have more than 100 km longer secure transmission distance and one order of magnitude enhancement in the key generation rate after 320 km compared with the standard method. Moreover, our model can still break the Pirandola–Laurenza–Ottaviani–Banchi (PLOB) bound even under realistic experimental conditions.