We report on the implementation of quantum entanglement distribution and quantum state teleportation over a 14.4 km urban dark-fiber link, which is partially underground, partially overhead, and patched in several stations. We characterize the link for its use as a quantum channel and realize its active polarization stabilization. Using a type-II cavity-enhanced SPDC photon pair source, a ⁴⁰Ca⁺ single-ion quantum memory, and quantum frequency conversion to the telecom C-band, we demonstrate photon-photon entanglement, ion-photon entanglement, and teleportation of a qubit state from the ion onto a remote telecom photon, all realized over the urban fiber link.

我们报告了在 14.4 公里长的城市暗光纤链路上实施量子纠缠分布和量子态隐形传输的情况，该链路部分位于地下，部分位于架空，并在多个站点进行了修补。我们描述了该链路作为量子通道的用途，并实现了其主动偏振稳定。使用 II 型腔增强型 SPDC 光子对源、 ⁴⁰ Ca ⁺单离子量子存储器以及电信 C 波段的量子频率转换，我们演示了光子-光子纠缠、离子-光子纠缠以及量子隐形传态。从离子到远程电信光子的量子位态，全部通过城市光纤链路实现。