Electro-optic frequency comb generation in lithium niobate photonic crystal Fabry-Perot micro-resonator

Integrated electro-optic (EO) combs offer compelling advantages in stability and tunability, but their performance has been constrained by weak modulation efficiency, parasitic Raman scattering, and the difficulty of achieving broad bandwidth within a compact footprint. We demonstrate EO frequency comb generation in a dispersion-engineered photonic crystal Fabry–Pérot (PhC-FP) micro-resonator in thin-film lithium niobate. Hundreds of standing-wave resonant modes with quality factors exceeding 10⁶ are supported within a photonic bandgap, while Raman-scattering bands are excluded. Integrated dispersion, primarily shaped by PhC reflectors, includes the zero-dispersion point for phase-matched EO modulation. Consequently, Raman-free EO combs are achieved under high on-chip pump powers of up to 200 mW. Comb characteristics are reconfigurable via microwave power, frequency detuning, and pump wavelength. This platform offers a compact, chip-integrated solution that provides broadband generation, high-power operation, and reconfigurability for EO comb sources in nonlinear and quantum photonic systems.