Modelling Brillouin activated microcombs in multi-layered silicon nitride waveguides

We investigate a numerical model to simulate the optical frequency comb generation in Kerr and Brillouin active resonators with gain parameters in the same order of magnitude. We show that either a backward or forward comb can be generated directly on a Brillouin laser or a cascaded Brillouin lasing mode respectively for a multi-layered silicon nitride waveguide structure.