  Nanophotonic quantum devices can significantly boost light-matter interaction
which is important for applications such as quantum networks. Reaching a high
interaction strength between an optical transition of a spin system and a
single mode of light is an essential step which demands precise control over
all degrees of freedom of the optical coupling. While current devices have
reached a high accuracy of emitter positioning, the placement process remains
overall statistically, reducing the device fabrication yield. Furthermore, not
all degrees of freedom of the optical coupling can be controlled limiting the
device performance. Here, we develop a hybrid approach based on
negatively-charged silicon-vacancy center in nanodiamonds coupled to a mode of
a Si$_3$N$_4$-photonic crystal cavity, where all terms of the coupling strength
can be controlled individually. We use the frequency of coherent
Rabi-oscillations and line-broadening as a measure of the device performance.
This allows for iterative optimization of the position and the rotation of the
dipole with respect to individual, preselected modes of light. Therefore, our
work marks an important step for optimization of hybrid quantum photonics and
enables to align device simulations with real device performance.
