The past decade has seen tremendous progress in experimentally realizing the building blocks of quantum repeaters. Repeater architectures with multiplexed quantum memories have been proposed to increase entanglement distribution rates, but an open challenge is to maintain entanglement fidelity over long-distance links. Here, we address this with a quantum router architecture comprising many quantum memories connected in a photonic switchboard to broker entanglement flows across quantum networks. We compute the rate and fidelity of entanglement distribution under this architecture using an event-based simulator, finding that the router improves the entanglement fidelity as multiplexing depth increases without a significant drop in the entanglement distribution rate. Specifically, the router permits channel-loss-invariant fidelity, i.e. the same fidelity achievable with lossless links. Furthermore, this scheme automatically prioritizes entanglement flows across the full network without requiring global network information. The proposed architecture uses present-day photonic technology, opening a path to near-term deployable multi-node quantum networks.

在过去的十年中，在实验实现量子中继器的构建模块方面取得了巨大进展。已经提出具有多路复用量子存储器的中继器架构来提高纠缠分布率，但一个开放的挑战是在长距离链路上保持纠缠保真度。在这里，我们使用一个量子路由器架构来解决这个问题，该架构包括许多量子存储器，这些量子存储器连接在一个光子交换机中，以代理跨量子网络的纠缠流。我们使用基于事件的模拟器计算了这种架构下纠缠分布的速率和保真度，发现随着复用深度的增加，路由器提高了纠缠保真度，而纠缠分布速率没有显着下降。具体来说，路由器允许信道损失不变保真度，即 无损链接可实现相同的保真度。此外，该方案自动优先考虑整个网络中的纠缠流，而不需要全局网络信息。提议的架构使用当今的光子技术，为近期可部署的多节点量子网络开辟了道路。