  Superconducting nanowire avalanche single-photon detectors (SNAPs) with n
parallel nanowires are advantageous over single-nanowire detectors because
their output signal amplitude scales linearly with n. However, the SNAP
architecture has not been viably demonstrated for n > 4. To increase n for
larger signal amplification, we designed a multi-stage, successive-avalanche
architecture which used nanowires, connected via choke inductors in a
binary-tree layout. We demonstrated an avalanche detector with n = 8 parallel
nanowires and achieved eight-fold signal amplification, with a timing jitter of
54 ps.
