  Superconducting detectors are now well-established tools for low-light
optics, and in particular quantum optics, boasting high-efficiency, fast
response and low noise. Similarly, lithium niobate is an important platform for
integrated optics given its high second-order nonlinearity, used for high-speed
electro-optic modulation and polarization conversion, as well as frequency
conversion and sources of quantum light. Combining these technologies addresses
the requirements for a single platform capable of generating, manipulating and
measuring quantum light in many degrees of freedom, in a compact and
potentially scalable manner. We will report on progress integrating tungsten
transition-edge sensors (TESs) and amorphous tungsten silicide superconducting
nanowire single-photon detectors (SNSPDs) on titanium in-diffused lithium
niobate waveguides. The travelling-wave design couples the evanescent field
from the waveguides into the superconducting absorber. We will report on
simulations and measurements of the absorption, which we can characterize at
room temperature prior to cooling down the devices. Independently, we show how
the detectors respond to flood illumination, normally incident on the devices,
demonstrating their functionality.
