Weak avalanche discrimination for gated-mode single-photon avalanche photodiodes

The after-pulsing effect is a common problem that needs to be overcome for high-speed single-photon detection based on gated-mode single-photon avalanche photodiodes (SPADs). This paper presents a simple and practical method for suppression of the after-pulsing probability using an auxiliary signal to discriminate quite weak avalanches. The detection efficiency and after-pulse probability of an InGaAs/InP SPAD are investigated with a 10 MHz gating for conventional and proposed methods, and a sharp decrease of after-pulse probability is demonstrated with the application of the proposed method. At a gating frequency of 100 MHz, a detection efficiency of 10.4% is achieved with an after-pulse probability of 5.6% without dead time.