Solitons and frequency combs in silica microring resonators: Interplay of the Raman and higher-order dispersion effects

The influence of Raman scattering and higher order dispersions on solitons and frequency comb generation in silica microring resonators is investigated. The Raman effect introduces a threshold value in the resonator quality factor above which the frequency-locked solitons cannot exist, and instead, a rich dynamics characterized by generation of self-frequency-shifting solitons and dispersive waves is observed. A mechanism for broadening the Cherenkov radiation through Hopf instability of the frequency-locked solitons is also reported.