Opt Express. 2023 Mar 13;31(6):10673-10683. doi: 10.1364/OE.481974.
Photonic spatial quantum states are a subject of great interest for applications in quantum communication. One important challenge has been how to dynamically generate these states using only fiber-optical components. Here we propose and experimentally demonstrate an all-fiber system that can dynamically switch between any general transverse spatial qubit state based on linearly polarized modes. Our platform is based on a fast optical switch based on a Sagnac interferometer combined with a photonic lantern and few-mode optical fibers. We show switching times between spatial modes on the order of 5 ns and demonstrate the applicability of our scheme for quantum technologies by demonstrating a measurement-device-independent (MDI) quantum random number generator based on our platform. We run the generator continuously over 15 hours, acquiring over 13.46 Gbits of random numbers, of which we ensure that at least 60.52% are private, following the MDI protocol. Our results show the use of photonic lanterns to dynamically create spatial modes using only fiber components, which due to their robustness and integration capabilities, have important consequences for photonic classical and quantum information processing.
光子空间量子态是量子通信应用中非常感兴趣的一个课题。一个重要的挑战是如何仅使用光纤组件动态生成这些态。在这里，我们提出并实验演示了一种全光纤系统，该系统可以基于线性偏振模式动态切换到任何一般的横向空间量子比特态。我们的平台基于基于萨格纳克干涉仪的快速光开关，结合光子分束器和多模光纤。我们展示了在 5 ns 量级的空间模式之间的切换时间，并通过在我们的平台上演示基于测量设备无关（MDI）量子随机数生成器，证明了我们方案在量子技术中的适用性。我们连续运行发生器超过 15 小时，采集了超过 13.46 Gbits 的随机数，根据 MDI 协议，我们确保至少 60.52%是私有的。我们的结果表明，使用光子分束器仅使用光纤组件动态创建空间模式，由于其鲁棒性和集成能力，对光子经典和量子信息处理具有重要意义。
