Nanophotonic Quantum Storage at Telecommunication Wavelength

Quantum memories for light are important components for future long-distance quantum networks. We present on-chip quantum storage of telecommunication-band light at the single-photon level in an ensemble of erbium-167 ions in an yttrium orthosilicate photonic crystal nanobeam resonator. Storage times of up to 10 mu s are demonstrated with an all-optical atomic-frequency-comb protocol in a dilution refrigerator under a magnetic field of 380 mT. We show this quantum-storage platform to have high bandwidth, high fidelity, and multimode capacity, and we outline a path toward an efficient erbium-167 quantum memory for light.