A telecom-wavelength atomic quantum memory in optical fiber for heralded polarization qubits

TL;DR

This paper demonstrates a telecom-wavelength atomic quantum memory in optical fiber capable of storing and retrieving polarization-encoded heralded single photons, advancing practical quantum communication technologies.

Contribution

It introduces a novel atomic quantum memory in optical fiber for polarization qubits at telecom wavelengths, a key missing element for quantum networks.

Findings

Successful storage and retrieval of polarization states of heralded single photons.

Implementation of the atomic frequency comb protocol in erbium-doped fiber.

Proof-of-principle with potential for future quantum information processing.

Abstract

Photon-based quantum information processing promises new technologies including optical quantum computing, quantum cryptography, and distributed quantum networks. Polarization-encoded photons at telecommunication wavelengths provide a compelling platform for practical realization of these technologies. However, despite important success towards building elementary components compatible with this platform, including sources of entangled photons, efficient single photon detectors, and on-chip quantum circuits, a missing element has been atomic quantum memory that directly allows for reversible mapping of quantum states encoded in the polarization degree of a telecom-wavelength photon. Here we demonstrate the quantum storage and retrieval of polarization states of heralded single-photons at telecom-wavelength by implementing the atomic frequency comb protocol in an ensemble of erbium atoms doped into an optical fiber. Despite remaining limitations in our proof-of-principle demonstration such as small storage efficiency and storage time, our broadband light-matter interface reveals the potential for use in future quantum information processing.