Patent ID: 7088824

Claim:
A single photon generating apparatus comprising: a photon pair source configured to generate a photon pair consisting of a signal photon and an idler photon that correlate with a generating time; a photon detector configured to detect an incidence of the idler photon and to generate a signal in response to the detected incidence of the idler photon; a clock generator configured to generate a clock pulse; a gate device controller configured to generate a control signal in response to the signal received from the photon detector; and a gate device configured to open or close in response to the control signal received from the gate device controller to control an emission of the signal photon. wherein said gate device opens only for the control signal corresponding to a first occurrence of the detected incidence of the idler photon within a predetermined time interval in the clock pulse, said predetermined time interval being such a short time as to allow said gate device to output only a single photon, and to suppress an emission of a succeeding single photon.