We present a heralded photon source based only on linear optics and weak coherent states. By time-tuning a Hong-Ou-Mandel interferometer fed with frequency-displaced coherent states, the output photons can be synchronously heralded following sub-Poisson statistics, which is indicated by the second-order correlation function $\mathrm{[}{g}^2\left(0\right)=0.556]$. The absence of phase-matching restrictions makes the source widely tunable, with 100-nm spectral tunability on the telecom bands. The technique presents yield comparable to state-of-the-art spontaneous parametric down-conversion-based sources, with high coherence and fiber-optic quantum communication compatibility.

• Received 9 June 2015

DOI:https://doi.org/10.1103/PhysRevA.92.033855