  Manipulation of the dynamics of cavity solitons, precise control of frequency
comb spectra and nonlinear response of microresonators through exploitation of
the ultrafast optical properties of graphene can have an immense impact on the
technological advancement of on-chip photonic devices. Here, we report that an
efficient self-frequency blueshifted frequency comb at optical and
near-infrared wavelengths can be achieved owing to the near-instantaneous
free-carrier dynamics of graphene in a realistic graphene-covered silicon
nitride microresonator. We perform a stability analysis to find the region of
stable cavity soliton excitation, which reveals that the nonlinearity of
graphene helps in improving the performance of the devices.
