Lithium-niobate-on-insulator waveguide-integrated superconducting nanowire single-photon detectors

We demonstrate waveguide-integrated superconducting nanowire single-photon detectors on thin-film lithium niobate (LiNbO3, LN). Using a 250 mu m-long NbN superconducting nanowire lithographically defined on top of a 125 mu m-long LN nanowaveguide, an on-chip detection efficiency of 46% is realized with simultaneous high performance in dark count rates and timing jitter. As LN possesses high chi ( 2 ) second-order nonlinear and electro-optic properties, an efficient single-photon detector on thin-film LN opens up the possibility to construct a small-scale fully integrated quantum photonic chip, which includes single-photon sources, filters, tunable quantum gates, and detectors.