Fig. 1. Block diagram of high-speed sine gated single-photon detector

Fig. 2. Afterpulse suppression scheme based on detection event time measurement. （a） Block diagram; （b） Time sequence diagram

Fig. 3. Block diagram of afterpulse measurement system for single-photon detector

Fig. 4. Normalization of time measurement results for detecting pulses

Fig. 5. Detection pulse count distribution （the discard time is 100 ns）

Fig. 6. Afterpulses triggered by avalanche signals that do not pass the discrimination threshold

Fig. 7. Afterpulse probability changes with different discard times of single-photon detector

Fig. 8. Detection pulses with different arrival times