Independent telecom-fiber sources of quantum indistinguishable single photons

Quantum-mechanically indistinguishable photons produced by independent (or equivalently, mutually phase incoherent) light sources are essential for distributed quantum information processing applications. We demonstrate heralded generation of such photons in two spatially separate telecom-fiber spools, each driven by pulsed pump waves that are measured to have no mutual phase coherence. Through HongOuMandel experiments, we measure the quantum interference visibility of those photons to be 76.4 ∓4.2%. Our experimental results are well predicted by a quantum multimode theory we developed for such systems without the need for any fitting parameter.