Double-Terminal Quenching Topology for Threefold After-Pulsing Reduction: Model and Experimental Validation

Single-photon avalanche diodes (SPADs) have emerged as crucial devices across a multitude of applications, ranging from fluorescence lifetime imaging (FLIM) to quantum technologies and light detection and ranging (LiDAR) systems. The increasing demand for fastening the acquisition rate of these applications has spurred significant interest in minimizing the SPAD dead time (DT) to a few nanoseconds. However, attempts to minimize its duration often exacerbate the after-pulsing (AP) phenomenon, posing a significant challenge in optimizing system performance. In this article, we propose a novel strategy to address this trade-off. We introduce a method that exploits passive or active quenching at the cathode terminal of SPADs, combined with an active quenching circuit (AQC) at the anode node. This combined approach aims at mitigating AP effects while simultaneously minimizing DT. We developed a comprehensive model and validation methodology to rigorously evaluate the effectiveness of this strategy. Finally, we demonstrate that how it is possible to achieve a strong reduction inAP compared with standard approaches.