%0 Journal Article %T Mid-Infrared Soliton and Raman Frequency Comb Generation in Silicon Microrings %A Tobias Hansson %A Daniele Modotto %A Stefan Wabnitz %J Physics %D 2014 %I arXiv %R 10.1364/OL.39.006747 %X We numerically study the mechanisms of frequency comb generation in the mid-infrared spectral region from cw pumped silicon microring resonators. Coherent soliton comb generation may be obtained even for a pump with zero linear cavity detuning, through suitable control of the effective lifetime of free-carriers from multiphoton absorption, which introduces a nonlinear cavity detuning via free-carrier dispersion. Conditions for optimal octave spanning Raman comb generation are also described. %U http://arxiv.org/abs/1409.3047v1