  One important building block for future integrated nanophotonic devices is
the scalable on-chip interfacing of single photon emitters and quantum memories
with single optical modes. Here we present the deterministic integration of a
single solid-state qubit, the nitrogen-vacancy (NV) center, with a photonic
platform consisting exclusively of SiO$_2$ grown thermally on a Si substrate.
The platform stands out by its ultra-low fluorescence and the ability to
produce various passive structures such as high-Q microresonators and mode-size
converters. By numerical analysis an optimal structure for the efficient
coupling of a dipole emitter to the guided mode could be determined.
Experimentally, the integration of a preselected NV emitter was performed with
an atomic force microscope and the on-chip excitation of the quantum emitter as
well as the coupling of single photons to the guided mode of the integrated
structure could be demonstrated. Our approach shows the potential of this
platform as a robust nanoscale interface of on-chip photonic structures with
solid-state qubits.
