  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.
