在实际的量子密钥分发(QKD)系统中,光源参数会随着时间、 环境的变化而抖动,导致QKD的成码率等性能下降。提出一种减轻光源抖动对QKD性能影响的方法。该方 法用标记相干态光源代替广泛使用的弱相干态光源,可以有效地提高QKD在光源抖动下的安全密钥生成率, 克服光源抖动对QKD性能的影响,并增大传输距离。通过理论分析和数值仿真验证了所提出方法的可行性, 该方法为QKD的实际应用提供了一种思路。

In the real quantum key distribution (QKD) system, statistical fluctuation of the source parameters will happen with the changes of time and environment, which will lead to a serve decrease of the key rate. Regarding to the problem, a method is proposed to eliminate the influence of statistical fluctuation of the source parameters on the performance of QKD. In the method, the heralded coherent sources are used to replace the widely used weak coherent sources, which can significantly improve the key rate of QKD when there is statistical fluctuation on the source parameters, and thus the influence of statistical fluctuation on the source parameters is eliminated, while the maximum transmission distance is also significantly improved. Both the theoretical analysis and numerical simulation verify the feasibility of the proposed method, and it is believed that the method can provide a new idea for the practical application of QKD.