Optimization of Dead Time in SPAD-based Photon-Counting Communication System with Afterpulsing

Afterpulsing is a critical non-ideal factor of single photon avalanche diode (SPAD) at telecommunication wavelength, which limits its performance. In order to optimize the dead time in SPAD operation, a multiple exponential model of afterpulsing probability (AP) is built and fitted with the testing data of QCD-300 single photon detector. Furthermore, a new bit error rate (BER) model of photon-counting communication system with afterpulsing is studied. Based on the joint model of AP and BER, the optimization of dead time in different bit times and background photon levels is investigated. The results indicate that the optimal dead time is constant with the variation of bit time. When background photon level increases, the optimal dead time will be increased quickly. And keeping the background photon level below 0.5-c/ns, the optimal dead time is below 32-ns.