InGaAsSPAD and electronics for low time jitter and low noise

We demonstrate that III-V photodetectors operated with dedicated front-end electronics and cooled at sufficiently low temperature (220 K or lower) can be exploited as Single-Photon Avalanche-Diodes (SPAD) for near-infrared photon counting and timing. Low dark-count rate can be achieved in gated-mode operation, though InGaAs/InP SPADs are plagued by strong avalanche carrier trapping that leads to afterpulsing. In order to reach the best performance, we designed fast circuits for gating SPADs and properly sensing the photon-induced avalanche pulse, cancelling spurious spikes due to gate transients thus accurately extracting photon timing information, and reducing avalanche charge thus minimizing afterpulsing. We report the results obtained with In0.53Ga0.47As/InP SPADs employing an integrated Active Quenching Circuit, designed for gated-mode operation at cryogenic temperature, and a fast signal pick-up network for extracting the best timing resolution. The joint use of a good InGaAs/InP detector and the presented electronics allows to reach low dark count rate (below 20 kHz), low time jitter (about 40 ps(FWHM)), high operation frequency (up to 100 kHz) with limited afterpulsing even when the photodetector is enabled for long gate-on times (even longer than 100 ns).