Timing adjustment of incoming photons in gated-mode single-photon detection at 1550nm

In gated-mode single-photon detection using an avalanche photodiode, a short gate is desirable for low-noise operation. In this case, afterpulse generation can be suppressed by optimizing the timing of incoming photons. Using a discharge pulse rather than a photon-induced avalanche for single-photon detection, we demonstrated afterpulse-suppressed single-photon detection at 1550 nm. By slightly changing the timing of incoming photons, the signal-to-noise ratio could be improved at the expense of reduced detection efficiency.