  Integrated quantum photonic circuits require the efficient coupling of photon
sources to photonic waveguides. Hybrid plasmonic/photonic platforms are a
promising approach, taking advantage of both plasmon modal confinement for
efficient coupling to a nearby emitter and photonic circuitry for optical data
transfer and processing. In this work, we established directional quantum dot
(QD) emission coupling to a planar TiO$_2$ waveguide assisted by a Yagi-Uda
antenna. Antenna on waveguide is first designed by scaling radio frequency
dimensions to nano-optics, taking into account the hybrid plasmonic/photonic
platform. Design is then optimized by full numerical simulations. We fabricate
the antenna on a TiO$_2$ planar waveguide and deposit a few QDs close to the
Yagi-Uda antenna. The optical characterization shows clear directional coupling
originating from antenna effect. We estimate the coupling efficiency and
directivity of the light emitted into the waveguide.
