Frequency comb generation in SNAP fiber resonator based on axial-azimuthal mode interactions

We study nonlinear mode interaction in the cylindrical microresonator with nanoscale radius variation. We obtain a model which describes the interplay between azimuthal modes and investigate the nonlinear dynamics of axial-azimuthal modes. We also define regimes of generation depending on the pump parameters. Using a properly designed radius longitudinal profile, we obtain broadband generation of stable low-repetition-rate frequency combs based on axial-azimuthal modes. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement