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 LiDAR systems. The increasing demand of fastening the acquisition rate of these application has spurred significant interest in minimizing the SPAD dead-time to a few nanoseconds. However, attempts to minimize its duration often exacerbate the after-pulsing phenomenon, posing a significant challenge in optimizing system performance. In this paper, 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 at the anode node. This combined approach aims at mitigating after-pulsing effects while simultaneously minimizing dead time. We developed a comprehensive model and validation methodology to rigorously evaluate the effectiveness of this strategy. Finally, we demonstrate how it is possible to achieve a strong reduction in after-pulsing compared to standard approaches.