  We demonstrate niobium titanium nitride superconducting nanowires patterned
on stoichiometric silicon nitride waveguides for detecting visible and infrared
photons. The use of silicon nitride on insulator on silicon substrates allows
us to simultaneously realize photonic circuits for visible and infrared light
and integrate them with nanowire detectors directly on-chip. By implementing a
traveling wave detector geometry in this material platform, we achieve
efficient single photon detection for both wavelength regimes. Our detectors
are an ideal match for integrated quantum optics as they provide crucial
functionality on a wideband transparent waveguide material.
