Chip integrated single photon generation by active time multiplexing

A system including a photonic integrated circuit for converting signal and idler photons generated by nonlinear optics into a deterministic stream of single photons, comprising:

• an optical element for receiving a heralded, nondeterministic source of signal and idler photons from the nonlinear optics;
• a separating element, adapted to intercept an emission path from the nonlinear optics, for separating one or more signal photons from one or more temporally corresponding idler photons received by the optical element;
• a variable delay circuit, optically coupled to the separating element, adapted to receive the one or more signal photons therefrom, and configured to delay the emission of at least one of the one or more signal photons by a variable optical buffer;
• and
• a heralding decision control, operatively coupled to the variable delay circuit, optically coupled to the separating element, adapted to receive the one or more idler photons therefrom, and configured to determine whether at least one of the one or more signal photons should enter the variable delay circuit, and if so, a delay length of the variable optical buffer.