  We have performed a detailed study of the dependence of afterpulse
probability in InGaAs/InP sine-gated SPAD on the dead time and the existing
approach for its implementation. We demonstrated an electrical scheme combining
sinusoidal gating and active reset. We have shown when such solutions are
beneficial from the key distribution point of view and enough to use a simple
scheme with a snatching comparator. We have also proposed a precise method for
measuring the afterpulse and presented a model describing the non-markovian
dynamic of this effect. We have demonstrated that our afterpulsing measurement
approach makes these measurements less dependent on the parameters of the flow
of the diode and the laser pulses power changes, in contrast to the other
methods considered in this paper.
