High-speed photon-number resolving with sinusoidally gated multipixel photon counters

We demonstrate a high-speed photon-number-resolving detector based on a sinusoidally gated multipixel photon counter (MPPC) at a repetition rate of 200 MHz. Two steps of low-pass filters are used to minimize the MPPC's capacitive response noise in sinusoidally gated Geiger mode, resulting in the efficient detection of weak photon-induced avalanche currents. Compared with passive quenching schemes, the sinusoidal gating scheme is conducive to shortening the recovery time for each pixel of the MPPC to detect the next coming photons, thus improving the detector's photon-number-resolving capability at a high repetition rate. The gated MPPC can identify the photon numbers of the incident pulses with a repetition frequency of 50 MHz clearly at as high as an average of 7.22 photons/pulse detected before saturation at room temperature.