On-demand quantum storage of photonic qubits in an on-chip waveguide

TL;DR

This paper demonstrates on-demand storage of photonic qubits in an integrated on-chip waveguide quantum memory with high fidelity, advancing practical quantum network applications.

Contribution

It introduces a novel on-chip quantum memory capable of on-demand qubit storage and retrieval with high fidelity using a Stark modulated atomic frequency comb protocol.

Findings

Achieved 99.3% storage fidelity for time-bin qubits.

Demonstrated on-demand retrieval of photonic qubits.

Surpassed classical measure-and-prepare fidelity limits.

Abstract

Photonic quantum memory is the core element in quantum information processing (QIP). For the scalable and convenient practical applications, great efforts have been devoted to the integrated quantum memory based on various waveguides fabricated in solids. However, on-demand storage of qubits, which is an essential requirement for QIP, is still challenging to be implemented using such integrated quantum memory. Here we report the on-demand storage of time-bin qubits in an on-chip waveguide memory on the surface of a $^{151}$Eu$^{3+}$:Y$_2$SiO$_5$ crystal, utilizing the Stark modulated atomic frequency comb protocol. A qubit storage fidelity of $99.3\%\pm0.2\%$ is obtained with a input of 0.5 photons per pulse, far beyond the highest fidelity achievable using the classical measure-and-prepare strategy. The developed integrated quantum memory with the on-demand retrieval capability, represents an important step towards practical applications of integrated quantum nodes in quantum networks.