  We investigate theoretically and experimentally the mode interaction in an
integrated Silicon Nitride (Si3N4) microring resonator with interferometric
coupling realized by a feedback loop as an adjustable optical path path length
connecting the ring to the bus waveguide at two coupling sections. From the
transmission spectra recorded at different optical path lengths, two
resonances, 1596.5~nm and 1570.5~nm, were selected for detailed investigation.
Both resonances show the possibility of adjusting the resonance width and
depth. However, the transmission spectra around the first resonance also show
the effect of mode interaction. This is also well captured in the theoretical
model, from which we can derive a coupling rate for the mode interaction of
$3.4~\textrm{rad}~\textrm{ns}^{-1}$.
