Brillouin-Enhanced Hyperparametric Generation of an Optical Frequency Comb in a Monolithic Highly Nonlinear Fiber Cavity Pumped by a cw Laser

We demonstrate self-seeded generation of a broadband comb in a highly nonlinear fiber resonator. When pumped with a cw laser, the fiber cavity generates a comb with two characteristic spacings. Hyperparametric modes spaced by similar to 2 THz create the base structure of the comb, while commensurate Brillouin modes spaced by similar to 10 GHz populate the intermediate frequency gaps. The frequency modes are coherent, and the repetition rate of the comb has been locked to a microwave standard.