Dually-pumped Kerr microcombs for spectrally pure radio frequency signal generation and time-keeping

A Kerr cavity soliton stabilization technique based on excitation by two continuous-wave pumps is proposed and theoretically and numerically investigated. Slow scanning of the second pump frequency near a comb harmonic of the soliton excited by the main pump locks the auxiliary pump to the soliton within a locking range. With the pumps locked to two frequency references, comb degrees of freedom will be stabilized. Evidence of stabilization and control of comb repetition rate using this technique is presented and the connection of duallypumped microcombs to "tiime crystals" is highlighted. The proposed approach extends to form a universal framework expounding soliton crystallization in microresonators supporting dispersive waves emitted by higherorder dispersion or mode anti-crossing. It can also obviate the exacting demand of octave-spanning combs for self-referencing.