The linear constraint of secret key rate capacity is overcome by the tiwn-field quantum key distribution (QKD). However, the complex phase-locking and phase-tracking technique requirements throttle the real-life applications of twin-field protocol. The asynchronous measurement-device-independent (AMDI) QKD or called mode-pairing QKD protocol [PRX Quantum 3, 020315 (2022), Nat. Commun. 13, 3903 (2022)] can relax the technical requirements and keep the similar performance of twin-field protocol. Here, we propose an AMDI-QKD protocol with a nonclassical light source by changing the phase-randomized weak coherent state to a phase-randomized coherent-state superposition (CSS) in the signal state time window. Simulation results show that our proposed hybrid source protocol significantly enhances the key rate of the AMDI-QKD protocol, while exhibiting robustness to imperfect modulation of nonclassical light sources.

翻译：通过双场量子密钥分发（QKD）可突破密钥率容量的线性约束，然而其复杂相位锁定与相位追踪技术要求阻碍了双场协议的实际应用。异步测量设备无关（AMDI）QKD（或称模式配对QKD协议）[PRX Quantum 3, 020315 (2022), Nat. Commun. 13, 3903 (2022)]可放宽技术需求并保持与双场协议相近的性能。本文提出一种采用非经典光源的AMDI-QKD协议，通过将信号态时间窗口中的相位随机化弱相干态替换为相位随机化相干态叠加（CSS）。仿真结果表明，本文提出的混合光源协议显著提升了AMDI-QKD协议的密钥率，同时展现出对非经典光源不完美调制的鲁棒性。