Frequency Comb Generation Via Synchronous Pumped Χ^(3) Resonator on Thin-Film Lithium Niobate

Resonator-based optical frequency comb generation is an enabling technologyfor a myriad of applications ranging from communications to precisionspectroscopy. These frequency combs can be generated in nonlinear resonatorsdriven using either continuous-wave (CW) light, which requires alignment of thepump frequency with the cavity resonance, or pulsed light, which also mandatesthat the pulse repetition rate and cavity free spectral range (FSR) arecarefully matched. Advancements in nanophotonics have ignited interest inchip-scale optical frequency combs. However, realizing pulse-driven on-chipKerr combs remains challenging, as microresonator cavities have limited tuningrange in their FSR and resonance frequency. Here, we take steps to overcomethis limitation and demonstrate broadband frequency comb generation using aχ^(3) resonator synchronously pumped by a tunable femtosecond pulsegenerator with on-chip amplitude and phase modulators. Notably, employingpulsed pumping overcomes limitations in Kerr comb generation typically seen incrystalline resonators from stimulated Raman scattering.