Numerical studies on Kerr comb generation in Si3N4 resonators with frequency dependent access coupler properties

Numerical studies on Kerr frequency comb generation with vertically-coupled whispering-gallery-mode (WGM) Si3N4 resonators are presented. These resonators include a frequency-dependent access coupler and are characterized by a free spectral range (FSR) of 220 GHz. We present numerical simulations based on the Ikeda map that allows implementation of complex-valued frequency-dependent and non-reciprocal access coupler transfer matrix in the simulation of Kerr comb in the cavities modelled by Arlotti et al(1). We use a Runge-Kutta 4 Interaction picture (RK4IP) method with adaptive step-size control as developed by Balac et al(2) to circumvent the numerical burden added by this modelling approach and successfully simulate Kerr comb generation using an approach that accurately models any optical cavity that can be considered as spatially one-dimensional regardless of its quality factor, finesse or dispersive properties which comes in useful in this study when access coupling properties degrade the resonator quality factor.