Fig. 1. Dispersion engineering of silicon-riched silicon nitride waveguide. (a) Silicon-riched silicon nitride waveguide cross-section diagram, eigenmodes in the waveguide with 2200 nm width and 600 nm height; (b) A_eff and γ of TE₀ mode; (c) simulated TE₀ mode GVD with 600 nm height while change waveguide width; (d) simulated TE₀ mode GVD with 2200 nm width while change waveguide height

Fig. 2. Dispersion engineering of silicon-riched silicon nitride microresonator. (a) Resonant mode frequency spacing D₁/(2π) of microresonator; (b) second-order dispersion D₂/(2π); (c) third-order dispersion D₃/(2π); (d) dispersion parameter D_int/(2π)

Fig. 3. Schematic of optical frequency comb generation through dual-frequency laser pumping normal dispersion silicon-riched silicon nitride microresonator

Fig. 4. Time-frequency evolution process of optical frequency comb generation in normal dispersion silicon-riched silicon nitride microresonator pumped by phase-locked dual-frequency laser. (a) Average intracavity power evolution with pump detuning; (b) evolution of time domain pulse and corresponding spectrum when pump detuning is 0; (c) evolution of time domain pulse and corresponding spectrum when pump detuning is 6; (d) evolution of time domain pulse and corresponding spectrum when pump detuning is 12; (e) evolution of time domain pulse and corresponding spectrum when pump detuning is 18; (f) evolution of time domain pulse and corresponding spectrum when pump detuning is 20

Fig. 5. Influence of input pump power on optical frequency comb generation. (a) Evolution of average intracavity power with pump detuning under different pump powers; (b) time-domain pulses with different pump powers when pulse intensity filling rate is same; (c) optical frequency comb spectra with different pump powers at the same pulse intensity filling rate

Fig. 6. Influence of dual-frequency laser power ratio on optical frequency comb generation. (a) Evolution of average intracavity power with pump detuning under different dual-frequency laser power ratios; (b) time-domain pulses with different laser power ratios when the pulse intensity filling rate is same; (c) optical frequency comb spectra with different laser power ratios at the same pulse intensity filling rate

Fig. 7. Influence of waveguide loss on optical frequency comb generation. (a) Evolution of average intracavity power with pump detuning under different waveguide losses; (b) time-domain pulses with different waveguide losses when the pulse intensity filling rate is same; (c) optical frequency comb spectra with different waveguide losses at the same pulse intensity filling rate

Fig. 8. Influence of microresonator dispersion on optical frequency comb generation. (a) Evolution of average intracavity power with pump detuning under different dispersions; (b) time-domain pulses with different dispersions when pulse intensity filling rate is same; (c) optical frequency comb spectra with different dispersions at the same pulse intensity filling rate

Fig. 9. Influence of dual-frequency laser frequency interval on optical frequency comb generation. (a) Evolution of average intacavity power with pump detuning under different frequency intervals; (b) time domain pulses with different frequency intervals when pulse intensity filling rate is same; optical frequency comb spectra with (c) one, (d) two, and (e) three FSR frequency intervals at the same pulse intensity filling rate