Storage and retrieval of heralded telecommunication-wavelength photons using a solid-state waveguide quantum memory

TL;DR

This paper demonstrates the storage and retrieval of heralded telecom-wavelength photons in a solid-state waveguide quantum memory, advancing quantum network technology compatible with existing fiber-optic infrastructure.

Contribution

It introduces a solid-state waveguide quantum memory capable of storing 1532 nm photons, a key step towards scalable quantum networks in the telecom band.

Findings

Successful storage and retrieval of telecom-wavelength photons

Memory enabled by population transfer into nuclear spin levels

Demonstration of on-chip quantum memory using industry-standard crystals

Abstract

Large-scale quantum networks will employ telecommunication-wavelength photons to exchange quantum information between remote measurement, storage, and processing nodes via fibre-optic channels. Quantum memories compatible with telecommunication-wavelength photons are a key element towards building such a quantum network. Here, we demonstrate the storage and retrieval of heralded 1532 nm-wavelength photons using a solid-state waveguide quantum memory. The heralded photons are derived from a photon-pair source that is based on parametric down-conversion, and our quantum memory is based on a 6 GHz-bandwidth atomic frequency comb prepared using an inhomogeneously broadened absorption line of a cryogenically-cooled erbium-doped lithium niobate waveguide. Using persistent spectral hole burning under varying magnetic fields, we determine that the memory is enabled by population transfer into niobium and lithium nuclear spin levels. Despite limited storage time and efficiency, our demonstration represents an important step towards quantum networks that operate in the telecommunication band and the development of on-chip quantum technology using industry-standard crystals.