Modelling superconducting nanowire single photon detectors in a waveguide cavity

Abstract

In this work we report on a single photon detector system which offers near-unity detection efficiency using waveguide-coupled superconducting nanowires with lengths on the order of 1 m.This is achieved by embedding the nanowires in a racetrack resonator where the interaction time with the photons trapped in the cavity is increased, thereby allowing for shorter nanowires.We expect this to lead to a higher fabrication yield as the amount of inhomogeneities decreases for shorter nanowires.Our simulations show a system with a 1 m long superconducting nanowire single photon detector (SNSPD) operating at near-unity detection efficiency using design parameters that can be realistically achieved with conventional fabrication processes.The resonant cavity introduces spectral selectivity to the otherwise broad-band SNSPDs and the cavity induced timing jitter is shown to be insignificant for SNSPDs longer than 1 m.