Raman suppressed microcombs in x-cut LiNbO3 photonic-crystal Fabry-Pérot microresonator

Thin-film lithium niobate (TFLN) is a key platform for integrated photonics, offering efficient electro-optic modulation, high second-order susceptibility, and broad optical transparency. However, in the widely used X-cut orientation, strong Raman nonlinearity in TE modes poses a significant challenge to Kerr microcomb generation. We demonstrate Kerr microcomb generation in an X-cut TFLN photonic-crystal Fabry-Pérot (PhC FP) resonator. By engineering the PhC bandgap to avoid the Raman gain bands, we successfully suppressed Raman scattering. This PhC FP dissipative engineering offers a broadly applicable solution for mitigating unwanted nonlinear effects in integrated photonic systems.