中间纠缠源离散调制CVQKD性能分析

连续变量量子密钥分发协议虽然具备更高的安全码 率等优势,但是其安全传输距离却一直表现不佳,而离散调制连续变量量子密钥分发协议已 被证明在低信噪比下能够获得比高斯调制更好的性能。基于 此,本文详细分析了光源非可信时,离散调制二态、四态和八态协议的性能,推导了安全码 率表达式。数 值仿真结果表明,当光源处于中间时,离散调制相干态零差检测正向协调性能优于其它协议 ,八态协议有更长的传输距离。

Performance analysis of discrete modulation continuous variable quantum key distribution with entanglement in the middle

Continuous variable quantum key distribution (CVQKD) has high secret key rate an d other advantages,which,however,are slightly insufficient in secure transmissio n distance and discrete modulation continuous variable quantum key distribution protocol has been proved to be able to obtain better performance than gaussian modulation with low signal-to-noise ra tio (SNR).Based on this,we analyze the performance of discrete modulation two-state,four-state and eight-state prot ocols in detail when the source is untrusted, drive the secret key rate expression.Numerical simulation results show that the discrete modulation coherent state and homodyne detection with direct reconciliation outperform all other protocols whe n the source in the middle,and the eight-state protocol has a longer transmissi on distance.