Deterministic solid state quantum light sources are considered key building blocks for future communication networks. While several proof-of-principle experiments of quantum communication using such sources have been realized, most of them required large setups—often involving liquid helium infrastructure or bulky closed-cycle cryotechnology. In this work, we report on the first quantum key distribution (QKD) testbed using a compact benchtop quantum dot single-photon source operating at telecom wavelengths. The plug&play device emits single-photon pulses at O-band wavelengths (1321 nm) and is based on a directly fiber-pigtailed deterministically fabricated quantum dot device integrated into a compact Stirling cryocooler. The Stirling is housed in a 19 in. rack module including all accessories required for stand-alone operation. Implemented in a simple QKD testbed emulating the BB84 protocol with polarization coding, we achieve an multiphoton suppression of $g^{(2)}(0)=0.10\pm 0.01$ and a raw key rate of up to $(4.72\hspace{0.17em}\pm \hspace{0.17em}0.13)$ kHz using an external pump laser. In this setting, we further evaluate the performance of our source in terms of the quantum bit error ratios, secure key rates, and tolerable losses expected in full implementations of QKD while accounting for finite key size effects. Furthermore, we investigate the optimal settings for a two-dimensional temporal acceptance window applied on the receiver side, resulting in predicted tolerable losses up to 23.19 dB. Not least, we compare our results with previous proof-of-concept QKD experiments using quantum dot single-photon sources. Our study represents an important step forward in the development of fiber-based quantum-secured communication networks exploiting sub-Poissonian quantum light sources.

中文翻译：

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使用即插即用电信波长单光子源的量子密钥分发测试台

确定性固态量子光源被认为是未来通信网络的关键组成部分。虽然已经实现了使用这些源进行量子通信的几个原理验证实验，但其中大多数都需要大型装置——通常涉及液氦基础设施或庞大的闭环低温技术。在这项工作中，我们报告了第一个量子密钥分发 (QKD) 测试平台，该测试平台使用在电信波长下运行的紧凑型台式量子点单光子源。即插即用设备发射 O 波段波长 (1321 nm) 的单光子脉冲，并基于集成到紧凑型斯特林低温冷却器中的直接光纤尾纤确定性制造的量子点设备。斯特林安装在一个 19 英寸的机架模块中，包括独立运行所需的所有附件。$G^{(2)}(0)=0.10\pm 0.01$和高达的原始密钥率$(4.72\hspace{0.17em}\pm \hspace{0.17em}0.13)$kHz 使用外部泵浦激光器。在这种情况下，我们进一步评估了我们的源的性能，包括量子比特错误率、安全密钥率和在 QKD 的完整实现中预期的可容忍损失，同时考虑了有限密钥大小的影响。此外，我们研究了在接收器侧应用的二维时间接受窗口的最佳设置，导致预测的可容忍损失高达 23.19 dB。尤其重要的是，我们将我们的结果与之前使用量子点单光子源的概念验证 QKD 实验进行了比较。我们的研究代表了利用亚泊松量子光源开发基于光纤的量子安全通信网络的重要一步。