Efficient single-photon frequency upconversion at 1.06 μm with ultralow background counts

Abstract

We demonstrated an efficient single-photon frequency upconversion system for the infrared photons at 1.06 μm with ultralow background counts. By pumping the system at a longer wavelength than that of the single-photon signal, the background counts caused by the pump-induced parametric fluorescence in the nonlinear crystal were reduced markedly. We achieved so far the lowest noise of ∼150/s for a near unity conversion efficiency.

On the genesis and evolution of Integrated Quantum Optics

“…Increasing quantum communication distances therefore amounts to improving the detection process, especially reducing the noise figure, since optical fiber technology has reached its theoretical limits in terms of propagation losses. Quantum communication scientists had the idea of hybrid up-conversion detection which seems to be a good alternative since it allows, at least theoretically, to translate photons from the telecom range to photons in the visible range via the association of the SFG process and permit the use of high performance Si-APDs [144][145][146][147][148][149][150][151][152][153][154].…”

Upconversion-based receivers for quantum hacking-resistant quantum key distribution

“…Note that any practically-useful definition of η c would include the waveguide's non-unity transmission, due to coupling and propagation losses in the nonlinear medium. The noise includes the intrinsic dark counts of the detector and those due to parasitic nonlinear interactions, such as pump-induced parametric fluorescence and spontaneous Raman scattering [10,44]. Based on the typical values of η c and η d reported in numerous experiments, achieving η ∼ 40% at a dark count probability below 10 −6 per signal pulse should be feasible with commercially available detectors [8,10].…”

Near-Infrared Single-Photon Detection

“…Unfortunately, these background photons can not be removed spectrally by the filters and contributed a lot to the dark counts on the Si-APD SPD. Several groups have proposed the long-wavelength pump scheme to overcome the troublesome up-converted parametric fluorescence (Langrock et al, 2004;Dong et al, 2008;Kamada et al, 2008). By choosing a comparatively long-wavelength pump, which means the energy of the pump photons is lower than that of the signal photons, the parametric fluorescence from the down conversion will not fall in the incident infrared signal photon spectral regime.…”

“…As a result, the pump induced parametric fluorescence can be efficiently suppressed and the dark counts will be greatly lowered. We have demonstrated an efficient single-photon frequency up-conversion system for the infrared photons at 1064 nm with ultralow dark counts (Dong et al, 2008). The pump source was provided by a mode-locked erbium-fiber laser.…”