Loss-tolerant BB84 Quantum Key Distributions with State Preparation and Measurement Imperfections

The source and detection modules serve as vital components of quantum key distribution (QKD) systems. Nonetheless, in practical applications, the efficiency of QKD systems is hindered by source flaws and detector imperfections. In this paper, based on the loss-tolerant method, we consider the impact of state preparation flaws and detection defects (afterpulse, dead-time) on BB84 QKD systems. Our simulation results show that with the the state preparation flaw, afterpulse probability and dead-time increase, although the key rate and the transmission distance reduces, the loss-tolerant BB84 QKD system is much more robust and show promising behaviors in practical implementations.