Telecom-heralded entanglement between remote multimode solid-state quantum memories

TL;DR

This paper demonstrates heralded entanglement between remote solid-state quantum memories that are compatible with telecom wavelengths and support multimode operation, advancing quantum network capabilities.

Contribution

It reports the first demonstration of telecom-heralded entanglement between remote multimode solid-state quantum memories with robust, multiplexed operation.

Findings

Heralded entanglement rate up to 1.4 kHz.

Storage of entanglement for up to 25 microseconds.

Operation with 62 temporal modes.

Abstract

Future quantum networks will enable the distribution of entanglement between distant locations and allow applications in quantum communication, quantum sensing and distributed quantum computation. At the core of this network lies the ability of generating and storing entanglement at remote, interconnected quantum nodes. While remote physical systems of various nature have been successfully entangled, none of these realisations encompassed all of the requirements for network operation, such as telecom-compatibility and multimode operation. Here we report the demonstration of heralded entanglement between two spatially separated quantum nodes, where the entanglement is stored in multimode solid-state quantum memories. At each node a praseodymium-doped crystal stores a photon of a correlated pair, with the second photon at telecommunication wavelengths. Entanglement between quantum memories placed in different labs is heralded by the detection of a telecom photon at a rate up to 1.4 kHz and is stored in the crystals for a pre-determined storage time up to 25 microseconds. We also show that the generated entanglement is robust against loss in the heralding path, and demonstrate temporally multiplexed operation, with 62 temporal modes. Our realisation is extendable to entanglement over longer distances and provides a viable route towards field-deployed, multiplexed quantum repeaters based on solid-state resources.