Investigating the Mechanism Behind the Formation of a Stable Sech²-Shaped Raman Comb in a Silica Microtoroid Driven by Continuous-Wave with Specific Dispersion

Recent experiments have shown that when a microresonator is pumped with coherent optical pulses under appropriate conditions, optical pulses with durations shorter than 50 fs can be generated [1]. These Raman solitons arise from the complex interplay between nonlinearity and dispersion, and their ultrashort duration makes them highly promising for applications that require high temporal resolution. Such solitons require precise control over the repetition rate of the pump pulse train and the round-trip time of the microresonator. However, theoretical analyses suggest that ultrashort Raman optical pulses will also exist under continuous-wave (CW) pumping conditions. We aim to explore the Raman soliton dynamics and the formation conditions using a microtoroid driven by CW.