Optical-Frequency Measurements with a Kerr Microcomb and Photonic-Chip Supercontinuum

The development of chip-scale frequency combs would enable precision optical-frequency measurements outside the laboratory, in real-world operating environments. Microresonators supporting soliton pulses provide an important step towards this goal, but reliable soliton stabilization and supercontinuum generation is challenging. The authors demonstrate streamlined soliton generation in a 15-GHz silica resonator, and chip-scale supercontinuum generation at 15-GHz pulse rates in a silicon nitride waveguide. Self-referencing this frequency-comb system with $f-2f$ interferometry has allowed them to measure the relative drift between two optical references, an important advance in metrology.