High speed single photon detection in the near infrared

InGaAs avalanche photodiodes (APDs) are convenient for single photon detection in the near infrared (NIR) including the fiber communication bands (1.31/1.55 mu m). However, to suppress afterpulse noise due to trapped avalanche charge, they must be gated with megahertz repetition frequencies, thereby severely limiting the count rate in NIR applications. Here, the authors show gating frequencies for InGaAs APDs well beyond 1 GHz. Using a self-differencing technique to sense much weaker avalanches, the authors reduce drastically afterpulse noise. At 1.25 GHz, they obtain a detection efficiency of 10.8% with an afterpulse probability of 6.16%. In addition, the detector features low jitter (55 ps) and a count rate of 100 MHz.