Silicon-on-insulator microrings both self-pulsate and are excitable due to the presence of thermal and free-carrier-related nonlinearities. We show how a dimensionless mean-field model, in which the fast light dynamics are neglected and only the temperature and the amount of free carriers remain as variables, can explain this dynamic behavior. Apart from a scaled detuning of the input wavelength to the resonance wavelength and a scaled input power, this system contains only a limited number of dimensionless parameters dependent on both the geometry and material system of the cavity. Moreover, the onset of oscillation is still analytically tractable, while the excitability onset can be obtained using continuation algorithms. In agreement with previous experiments, excitability is predicted to appear mainly at the blue side of the resonance. Finally, the proposed method of analysis paves the way for an easy comparison of the dynamics in different material systems or cavity types.

• Received 3 September 2012

DOI:https://doi.org/10.1103/PhysRevA.86.063808