Design and performance study of actively holding-off GHz-gated InGaAs/InP SPADs

摘要

High-speed periodic gating of InGaAs/InP single-photon avalanche diodes (SPADs) has allowed these detectorsto operate at count rates above 10~8 per second with low afterpulsing. However, a drawback of high-speed periodicgating is that bias gates are applied continuously, regardless of whether an avalanche has occurred or not. This isdisadvantageous because gates immediately following an avalanche have elevated afterpulse probabilities, and theadditional charge from these secondary events contributes to the overall afterpulse probability. We investigatethis phenomenon in a proof-of-principle experiment in which the series of bias gates is briey interrupted after anavalanche, and we measure the resulting impact on the afterpulse probability. We observe a significant reductionin afterpulsing when such a bias-gate hold-off is applied to an InGaAs/InP SPAD gated at 1.25 GHz; when onebias gate is omitted after an avalanche the per-gate afterpulse probability is reduced by more than 40 %. Theseresults indicate that afterpulsing noise at high count rates can be further reduced in high-speed-gated SPADs.