A heralded single-photon source for quantum communications compatible with long-distance optical fibers

This paper reports the implementation of a heralded single-photon source for quantum communications. Pump photons are parametric down-converted into pairs of photons at 810 and 1550 nm inside a non-linear crystal. The former acts as a heralding signal to the telecom wavelength photon. The temporal correlation between the photons is measured, as well as the compromise between source visibility and maximum achievable transmission distance.