title: A waveguide frequency converter connecting rubidium-based quantum memories to the telecom C-band.
abstract: Coherently converting the frequency and temporal waveform of single and entangled photons will be crucial to interconnect the various elements of future quantum information networks. Of particular importance is the quantum frequency conversion of photons emitted by material systems able to store quantum information, so-called quantum memories. There have been significant efforts to implement quantum frequency conversion using nonlinear crystals, with non-classical light from broadband photon-pair sources and solid-state emitters. However, solid state quantum frequency conversion has not yet been achieved with long-lived optical quantum memories. Here we demonstrate an ultra-low-noise solid state photonic quantum interface suitable for connecting quantum memories based on atomic ensembles to the telecommunication fibre network. The interface is based on an integrated-waveguide nonlinear device. We convert heralded single photons at 780 nm from a rubidium-based quantum memory to the telecommunication wavelength of 1,552 nm, showing significant non-classical correlations between the converted photon and the heralding signal.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels 08860, Spain.
authors.forename: Boris
authors.initials: B
authors.lastname: Albrecht
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels 08860, Spain.
authors.forename: Pau
authors.initials: P
authors.lastname: Farrera
authors.affiliation: 1] ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels 08860, Spain [2].
authors.forename: Xavier
authors.initials: X
authors.lastname: Fernandez-Gonzalvo
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels 08860, Spain.
authors.forename: Matteo
authors.initials: M
authors.lastname: Cristiani
authors.affiliation: 1] ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels 08860, Spain [2] ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona 08015, Spain.
authors.forename: Hugues
authors.initials: H
authors.lastname: de Riedmatten
mesh_terms: D000465:Algorithms; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation / Q000379:methods; D008962:Models, Theoretical; D017785:Photons; D011789:Quantum Theory; D012413:Rubidium / Q000737:chemistry*; D013685:Telecommunications / Q000295:instrumentation*
chemical_list: D012413:Rubidium