Frequency up-conversion single-photon detectors for quantum communication systems

Frequency up-conversion technology can be used to increase detection efficiency for near infrared photons, as has been demonstrated in fiber-based quantum communication systems. In a continuous wave pumped up-conversion detector, the temporal resolution is limited by the timing jitter of the detector in the visible range, which limits the maximum clock rate of a quantum communication system. In this paper we describe a scheme to improve the temporal resolution of an up-conversion single-photon detector using multi-wavelength optical-sampling techniques, allowing for increased transmission rates in single-photon communications systems. We experimentally demonstrate our approach with an up-conversion detector using two spectrally and temporally distinct pump pulses, and show that it allows for high-fidelity single-photon detection at twice the rate supported by a conventional single-pump up-conversion detector.