4 ns dead time with a fully integrated active quenching circuit driving a custom single photon avalanche diode.

At the present time, Single Photon Avalanche Diodes (SPADs) are the enabling devices in many applications, ranging from medical imaging to laser ranging and from remote sensing to quantum key distribution. Even though they belong to different scientific domains, these applications share the need for a detector capable of attaining high count rates possibly without trading it off with other key detector's features, such as afterpulsing probability, photon detection efficiency, and dark counts. In this work, we present the characterization of a fast integrated active quenching circuit capable of driving high-performance external custom-technology SPADs for single photon detection in the visible wavelength range. Combining the prompt intervention of the electronic circuitry and the performance of a custom-technology SPAD, we attained count rates up to 250 MCps while keeping the afterpulsing probability within 2%.