Experimental characterization of afterpulsing and timing jitter of InGaAs/InP SPAD

We present the characterization results on a recent generation of InGaAs/InP Single-Photon Avalanche Diodes (SPADs) operating up to 1700 nm. The improved performance makes them very promising for many NIR single-photon counting applications since they show low dark count rate, good photon detection efficiency and quite low timing jitter. First we characterized an important drawback of InGaAs/InP SPAD, namely afterpulsing: traps in the InP high-field region capture carriers during the avalanche current flow and release them with delay, thus triggering another avalanche and generating additional noise. Using the double pulse method, we measured the afterpulsing probability as a function of time delay from the avalanche triggering. We carried out measurements at different temperatures and at different excess bias in order to find the best operating conditions. Moreover, we biased the detector at different voltage levels during the OFF period, so as to change the electric field during the de-trapping period in order to study how it affects the carrier release. Then we characterized SPAD timing jitter, that leads to the time spread between photon absorption and avalanche detection. We measured timing jitter with focused and un-focused light in order to determine the effects of light absorption position on jitter.