School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 USA.
We report the first experimental demonstration of broadband frequency comb generation from a single-frequency pump laser at 1-μm using parametric oscillation in a high-Q silicon-nitride ring resonator. The resonator dispersion is engineered to have a broad anomalous group velocity dispersion region near the pump wavelength for efficient parametric four-wave mixing. The comb spans 55 THz with a 230-GHz free spectral range. These results demonstrate the powerful advantage of dispersion engineering in chip-based devices for producing combs with a wide range of pump wavelengths.