Efficient Storage of Multidimensional Telecom Photons in a Solid-State Quantum Memory

TL;DR

This paper demonstrates an efficient, high-fidelity quantum memory for telecom photons in a solid-state Erbium-doped crystal, advancing practical quantum network implementations.

Contribution

It introduces a novel memory initialization scheme that significantly improves storage efficiency under realistic conditions.

Findings

Over 92% fidelity in quantum process tomography

Enhanced storage efficiency by over an order of magnitude

Successful storage of polarization, frequency, and time-bin encoded qubits

Abstract

Efficient storage of telecom-band quantum optical information represents a crucial milestone for establishing distributed quantum optical networks. Erbium ions in crystalline hosts provide a promising platform for telecom quantum memories; however, their practical applications have been hindered by demanding operational conditions, such as ultra-high magnetic fields and ultra-low temperatures. In this work, we demonstrate the storage of telecom photonic qubits encoded in polarization, frequency, and time-bin bases. Using the atomic frequency comb protocol in an Er$^{3+}$-doped crystal, we developed a memory initialization scheme that improves storage efficiency by over an order of magnitude under practical experimental conditions. Quantum process tomography further confirms the memory's performance, achieving a fidelity exceeding 92%.