Experimental Characterization of APD and Design of Quenching Circuit for Single-Photon Detection

In this paper, we experimentally characterize the Inga As/Imp avalanche photodiode (APD), which is working in Geiger mode, so as to choose the single photon detector for quantum communication. Due to the fact that bias of APD tends to be flat after avalanche, we first adopt the methodology of passive quenching to determine dark breakdown voltage. Experiment results indicate that temperature reduction will widen the optimal operating region and increase the optimal multiplication; therefore APD will be more sensitive. Epitaxial APD is the best choice for single-photon detection among the APDs we have tested for its low noise level and high signal-to-noise ratio (SNR). Finally, we design a mixed passive-active quenching integrated circuit with gate control, which is quick with the quenching time of about 25ns and has controllable dead time with minimum of about 60ns.