High quality asynchronous heralded single photon source at telecom   wavelength
  We report on the experimental realization and characterization of an asynchronous heralded single photon source based on spontaneous parametric down conversion. Photons at 1550nm are heralded as being inside a single-mode fiber with more than 60% probability, and the multi-photon emission probability is reduced by up to a factor 600 compared to poissonian light sources. These figures of merit, together with the choice of telecom wavelength for the heralded photons are compatible with practical applications needing very efficient and robust single photon sources. 
Sylvain Fasel, Olivier Alibart, Alexios Beveratos, Sebastien Tanzilli,   Hugo Zbinden, Pascal Baldi, Nicolas Gisin