A technique to measure afterpulse probabilities in InGaAs SPADs at nanosecond time scales with sub-picoCoulomb avalanche charge

We adapt a previously-demonstrated gating technique for InGaAs SPADs to enable double-bias-pulse measurements of afterpulsing at nanosecond time scales with gate durations down to 500 ps. We present preliminary results for afterpulse probabilities below 10 ns, time scales comparable to those in the self-differencing technique, and show that afterpulse probabilities low enough to support reliable counting above 100 MHz can be observed.