  We demonstrate the integration of amorphous tungsten silicide superconducting
nanowire single-photon detectors on titanium in-diffused lithium niobate
waveguides. We show proof-of-principle detection of evanescently-coupled
photons of 1550nm wavelength using bidirectional waveguide coupling for two
orthogonal polarization directions. We investigate the internal detection
efficiency as well as detector absorption using coupling-independent
characterization measurements. Furthermore, we describe strategies to improve
the yield and efficiency of these devices.
