Brillouin-induced Kerr frequency comb in normal dispersion fiber Fabry Perot resonators

We report the generation of a stable, broadband frequency comb, covering more than 10 THz, using a dispersion fiber Fabry-Perot resonator with a high quality factor of 69 millions. This platform ensures robust and easy integration into photonic devices via FC/PC connectors, and feature quality factors comparable to those of microresonators. We demonstrate a passive mode-locking phenomenon induced by the coherent interaction of the Kerr effect and Brillouin scattering, which generates a frequency comb with a repetition rate exceeding the free spectral range of the cavity. This parametric process modulates the continuous wave (CW) pump and can then be transformed into a train of almost square-wave pulses thanks to the generation of switching waves. Our results are supported by advanced numerical simulations, and theoretical derivations that include the Brillouin effect in the Fabry-Perot configuration. The very high stable feature of this optical frequency comb lying in the GHz range is critical to several applications ranging from telecommunication, spectroscopy and advanced microwave generation. Optical frequency combs are key tools in spectroscopy and telecom. Here, authors report a stable and broadband comb (>10 THz) from a high-Q fiber Fabry-Perot resonator via Kerr-Brillouin passive mode-locking. This easily integrable platform ensures state-of-the-art photonic performance.