Realization of multiplexing of heralded single photon sources using photon number resolving detectors

Heralded single-photon sources (HSPS) are widely used in experimental quantum science because they have negligibly small jitter and can therefore achieve high visibility for quantum interference. However, it is necessary to decrease the photon generation rate to suppress multi-photon components. To address this problem, two methods have been proposed and discussed: spatial (or temporal) source multiplexing and photon-pair number discrimination. Here, we report the experimental realization of a HSPS combining these two methods that can suppress the two-photon probability to 44.2 ± 0.7% of that of a normal HSPS. We also provide a theoretical analysis and a discussion of the effect of combining the two methods, considering a detector cascade as a practical photon number discriminating detector. The experimental results agreed well with the theoretical predictions.