  We investigated the reset time of superconducting nanowire avalanche
photodetectors (SNAPs) based on 30 nm wide nanowires. We studied the dependence
of the reset time of SNAPs on the device inductance and discovered that SNAPs
can provide a speed-up relative to SNSPDs with the same area, but with some
limitations: (1) reducing the series inductance of SNAPs (necessary for the
avalanche formation) could result in the detectors operating in an unstable
regime; (2) a trade-off exists between maximizing the bias current margin and
minimizing the reset time of SNAPs; and (3) reducing the reset time of SNAPs
below ~ 1 ns resulted in afterpulsing.
