Improving the performance of practical reference-frame-independent quantum key distribution under the afterpulse effect

The article delves into the challenges and solutions for enhancing the performance of practical reference-frame-independent quantum key distribution (RFI-QKD) under the afterpulse effect. It begins by outlining the principles of QKD and the significance of RFI-QKD in future global-scale quantum internet. The afterpulse effect, a critical issue in single-photon avalanche detectors (SPADs), is thoroughly examined, highlighting its impact on the secret key rate. The article introduces the advantage distillation (AD) method, which identifies subsets of highly correlated bits from raw keys to enhance performance. Through a detailed analytical model and simulation results, the study demonstrates that the AD method significantly boosts the secret key rate and extends the maximal transmission distance of RFI-QKD. The simulations cover various scenarios, including different transmission distances and afterpulse probabilities, showcasing the robustness and effectiveness of the AD method in mitigating the performance decline caused by the afterpulse effect. The findings underscore the practical advantages of the AD method in improving RFI-QKD systems, making it a valuable contribution to the field of quantum key distribution.