Optical Frequency Comb generation in All-normal Silicon Nitride Waveguide

A silicon nitride waveguide has been used to numerically generate an optical frequency comb. The geometrical parameters of the waveguide were optimized for an all-normal dispersion profile. By employing a dual-wavelength pump around 1.55 µm in a 0.04 m long waveguide with all dispersion, a frequency comb spanning 80 nm and exhibiting a 10 dB bandwidth was achieved. Notably, this represents the first reported instance of a broadband frequency comb generated in a single-stage channel waveguide with small geometrical dimensions. Potential applications for this optical comb include optical atomic clocks, optical rulers, and wavelength division multiplexing.