Advantages of Asynchronous Measurement-Device-Independent Quantum Key Distribution in Intercity Networks

The alternative variant of measurement-device-independent quantum key distribution (MDI QKD), called asynchronous MDI QKD or mode-pairing MDI QKD, offers similar repeaterlike rate-loss scaling but has the advantage of simple technology implementation by exploiting an innovative postmeasurement pairing technique. We herein present an evaluation of the practical aspects of decoy-state asynchronous MDI QKD. To determine its effectiveness, we analyze the optimal method of decoy-state calculation and examine the impact of asymmetrical channels and multiuser networks. Our simulations show that, under realistic conditions, aynchronous MDI QKD can furnish the highest key rate with MDI security as com-pared to other QKD protocols over distances ranging from 50 to 480 km. At fiber distances of 50 and 100 km, the key rates attain 6.02 and 2.29 Mbps, respectively, which are sufficient to facilitate real-time one-time-pad video encryption. Our findings indicate that experimental implementation of asynchronous MDI QKD in intercity networks can be both practical and efficient.