Telecom photonic interface of disparate nodes in a hybrid quantum network*

Progress on various quantum networking platforms continues to improve the state-of-the-art in entanglement generation, storage, and other desirable capabilities. A hybrid network architecture can take advantage of the assets of various quantum platforms to create a modular network with more overall potential than a network built on a single platform. We are simultaneously developing a photon source node based on a warm atomic ensemble and a memory node based on a rare-earth ion-doped crystal. The source node uses spontaneous four-wave mixing in rubidium to produce heralded single telecom photons which can be stored and retrieved using the atomic frequency comb protocol in erbium-doped yttrium orthovanadate. Notably, the photonic interface operates directly at telecom to bypass lossy and noisy quantum frequency conversion to optimal wavelengths. For ideal mode-matching, we optimize the bandwidth of the source photons and apply an external magnetic field to bring the crystal to resonance with the telecom transition in rubidium. We report on our recent progress towards interfacing the two dissimilar quantum platforms. Additionally, we discuss plans for leveraging memory multimodality, connecting to other platforms, and extending the link over the Chicago-area quantum network.