Dispersion engineering for broadband visible microcombs via mode hybridization and inverse design

We propose a reliable and simple approach for dispersion engineering in lithium niobate microring resonators (MRRs). With strong coupling-induced mode hybridization and inverse design method, we overcome the large normal dispersion and achieve broadband frequency comb coverage near 525 nm. We adopt a neural network method in the inverse design, which outperforms the traditional forward design based on manual trial-and-error and intuitive judgment. Our numerical results demonstrate the possibility of generating a visible Kerr soliton microcomb with a bandwidth of 214.4 nm in a single MRR, which holds significant potential for applications in bioimaging and on-chip atomic clocks.