Quantum key distribution (QKD) is nowadays a well-established method for generating secret keys at a distance in an information-theoretically secure way, as the secrecy of QKD relies on the laws of quantum physics and not on computational complexity. In order to industrialize QKD, low-cost, mass-manufactured, and practical QKD setups are required. Hence, photonic and electronic integration of the sender’s and receiver’s respective components is currently in the spotlight. Here we present a high-speed (2.5 GHz) integrated QKD setup featuring a transmitter chip in silicon photonics allowing for high-speed modulation and accurate state preparation, as well as a polarization-independent low-loss receiver chip in aluminum borosilicate glass fabricated by the femtosecond laser micromachining technique. Our system achieves raw bit error rates, quantum bit error rates, and secret key rates equivalent to a much more complex state-of-the-art setup based on discrete components [A. Boaron, et al., Phys. Rev. Lett. 121, 190502 (2018)].

中文翻译：

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高速集成QKD系统

量子密钥分发 (QKD) 是当今一种行之有效的方法，用于以信息理论上安全的方式远距离生成密钥，因为 QKD 的保密性依赖于量子物理定律，而不是计算复杂性。为了实现 QKD 的工业化，需要低成本、大规模制造和实用的 QKD 设置。因此，发射器和接收器各自组件的光子和电子集成目前备受关注。在这里，我们展示了一种高速（2.5 GHz）集成 QKD 设置，其特点是硅光子发射器芯片允许高速调制和准确的状态准备，以及由硼硅酸铝玻璃制成的偏振无关低损耗接收器芯片飞秒激光微加工技术。我们的系统实现了原始误码率，量子误码率和密钥率等同于基于分立组件的更复杂的最先进设置 [A. 布伦，等。, 物理。牧师莱特。121 , 190502 (2018)]。