Telecom quantum networking with neutral atoms and rare-earth ions

A scalable quantum network capable of processing, storing, and communicating quantum information should leverage the complementary strengths of various quantum platforms and operate at telecom wavelengths. Coherently interfacing different quantum systems, however, can be challenging, as it requires frequency and bandwidth matching. Here, we propose a hybrid, three-node network architecture that operates directly at telecom, circumventing the need for frequency conversion, which typically introduces noise and limits efficiency. Our processor node consists of an atom array integrated with a nanophotonic chip, which enables the generation of atom-photon entanglement. Our photon source node utilizes phase-matched four-wave mixing in a warm atomic ensemble to create entangled photon pairs. Lastly, our memory node is based on a rare-earth ion-doped crystal where the atomic frequency comb protocol allows broadband, multimode storage of the photons sourced from our atom-based nodes. We present recent progress on implementing background-free imaging for the processor node and coupling the photon source node with the memory. Furthermore, we discuss the prospect of deploying the three modular nodes in a metropolitan quantum network in Chicago.