Extending thermal stability of short-living soliton states in silicon nitride microring resonators

Dissipative Kerr solitons in microresonators enable on-chip chip generation of low-noise optical pulse trains with high repetition rates, finding applications in optical communication, distance measurement, spectroscopy and radiofrequency generation. However, the most common photonic integrated platforms often show very short living, hence difficult to achieve, soliton states. Here, we exploit an auxiliary resonance to access soliton regime in Si3N4 microresonators by simple wavelength scanning. We increase the likelihood of single soliton formation by more than two times using backward tuning of the laser, and we show that the increased thermal stability allows soliton formation by thermal tuning of the whole sample, keeping the laser at a fixed frequency.