Quantum light sources emitting triggered single photons or entangled photon pairs have the potential to boost the performance of quantum key distribution (QKD) systems. Proof-of-principle experiments affirmed these prospects, but further efforts are necessary to push this field beyond its current status. In this work, we show that temporal filtering of single-photon pulses enables a performance optimization of QKD systems implemented with realistic quantum light sources, both in experiment and simulations. To this end, we analyze the influence of temporal filtering of sub-Poissonian single-photon pulses on the expected secret key fraction, the quantum bit error ratio, and the tolerable channel losses. For this purpose, we developed a basic QKD testbed comprising a triggered solid-state single-photon source and a receiver module designed for four-state polarization coding via the BB84 protocol. Furthermore, we demonstrate real-time security monitoring by analyzing the photon statistics, in terms of g⁽²⁾(0), inside the quantum channel by correlating the photon flux recorded at the four ports of our receiver. Our findings are useful for the certification of QKD and can be applied and further extended for the optimization of various implementations of quantum communication based on sub-Poissonian quantum light sources, including measurement-device-independent schemes of QKD as well as quantum repeaters. Our work represents an important contribution towards the development of QKD-secured communication networks based on quantum light sources.

发射触发的单光子或纠缠的光子对的量子光源具有提高量子密钥分配（QKD）系统性能的潜力。原理验证实验证实了这些前景，但是需要进一步的努力以使该领域超越目前的状态。在这项工作中，我们证明了在实验和仿真中，单光子脉冲的时间滤波可实现对用实际量子光源实现的QKD系统的性能优化。为此，我们分析了亚泊松单光子脉冲的时间滤波对预期秘密密钥分数，量子误码率和可容忍的信道损耗的影响。以此目的，我们开发了一个基本的QKD测试台，包括一个触发固态单光子源和一个通过BB84协议设计用于四态极化编码的接收器模块。此外，我们通过分析光子统计数据展示了实时安全监控，g ^（2）（0），通过关联在接收器的四个端口处记录的光子通量在量子通道内部。我们的发现对于QKD的认证很有用，可以应用于和进一步扩展基于亚泊松量子光源的量子通信的各种实现的优化，包括与测量设备无关的QKD方案以及量子中继器。我们的工作为基于量子光源的QKD安全通信网络的发展做出了重要贡献。