Broadband optical frequency comb generation in lithium niobate microring resonator by dispersion engineering

Abstract

Thin film lithium niobate (LN) is considered a promising platform for integrated photonics owing to its exceptional electro-, nonlinear-, and acousto-optic properties. In this work, we propose the generation of broadband optical frequency combs in an LN microring resonator by dispersion engineering. We design the structure of the LN waveguide to adjust the effective refractive index of its fundamental mode so that the microring resonator can generate two dispersive waves near the pump light to achieve a broadband optical frequency comb up to 4/5-octave range (about 110 THz). The broadband frequency comb is crucial for future on-chip LN nonlinear photonics applications.