Single photon frequency up-conversion and its applications

We have studied single photon level frequency up-conversion, and developed efficient single photon detectors and a highly sensitive spectrometer at a telecommunication wavelength (around 1310 nm). We have applied the detector and spectrometer to the implementation of a quantum key distribution system; to the characterization of an entangled photon source and a single photon source from quantum dots; to increase the temporal resolution of the single photon detector; and to study on high-order temporal correlation following frequency conversion. In this paper, we will present an overview on the frequency up-conversion technique and its applications in quantum information systems.