Soliton Formation in Whispering-Gallery-Mode Resonators via Input Phase Modulation

We propose a systematic method for soliton formation in whispering-gallery-mode (WGM) resonators through input phase modulation. Our numerical simulations of a variant of the Lugiato-Lefever equation (LLE) suggest that modulating the input phase at a frequency equal to the resonator free spectral range and at modest modulation depths provides a deterministic route toward soliton formation in WGM resonators without undergoing a chaotic phase. We show that the generated solitonic state is sustained when the modulation is turned off adiabatically. Our results support parametric seeding as a powerful means of control, in addition to input pump power and pump-resonance detuning, over frequency comb generation in WGM resonators. Our findings also help pave the way toward ultrashort pulse formation on a chip.