  We report on the implementation of quantum frequency conversion (QFC) between
infrared (IR) and ultraviolet (UV) wavelengths by using single-stage
upconversion in a periodically poled KTP waveguide. Due to the monolithic
waveguide design, we manage to transfer a telecommunication band input photon
to the wavelength of the ionic dipole transition of Yb${}^{+}$ at 369.5 nm. The
external (internal) conversion efficiency is around 5\% (10\%). The high energy
pump used in this converter introduces a spontaneous parametric downconversion
(SPDC) process, which is a cause for noise in the UV mode. Using this SPDC
process, we show that the converter preserves non-classical correlations in the
upconversion process, rendering this miniaturized interface a source for
quantum states of light in the UV.
