High-contrast microrings combine high Q factors and small cross section, allowing for strong nonlinear light-matter interaction at low optical power and group-velocity-dispersion management. Such cavities are used in an increasing set of photonic applications including frequency comb (OFC) generation. Over the last years, Kerr OFCs, generated in high-Q microresonators with cubic nonlinearities, have raised significant interest. They offer broadband spectra with uniform line powers, free spectral ranges up to 100's GHz, and chip-scale integration. Kerr “microcombs” thus open the potential to disrupt a series of highly relevant applications, ranging from massively parallel wavelength-division multiplexing in optical communications to high-resolution spectroscopy. Despite this potential, full deployment of Kerr combs is still hindered by stability and uniformity issues, plus limited spectral spanning. In addition, efficient schemes for controlling the carrier-envelope offset frequency of Kerr combs are still lacking, thereby impeding the application of Kerr combs in high-precision optical metrology and optical frequency standards. In this internship, by combining Kerr-type cubic with quadratic optical nonlinearities, we will explore and implement novel approaches for OFC generation in photonic integrated circuits, which enable a richer nonlinear dynamics and stabilized carrier-envelope offset frequency.