Fig. 3: ‘Set-and-forget’ operation, robust single soliton as a dominant attractor: recovery of the same single-soliton state from perturbations and long-term stability.

a, Output power of the single-soliton state. The system is perturbed three times with a mechanical disruption at roughly 7, 11 and 16 s (red arrow). b,c, Spectra of the system at 14.5 s (b) and 19.5 s (c), before and after the perturbation. d, Laser scanning spectroscopy of the 1,543 nm microcavity resonance under lasing condition. The frequency difference between the microcavity resonance centre (black dashed line) and the laser line (red line) defines the operative frequency detuning of the mode. e, Frequency detuning of a selection of microcomb lines extracted as in d. f,g, Same as d,e at 19.5 s. h, Long-term robustness of the state, showing roughly half an hour of continuous operation of a single-soliton state. Temporal evolution of the measured optical spectrum. The colour bar shows the optical power spectral density. i, Typical optical spectrum from h (taken at 20 min). j, Evolution of the radio-frequency spectrum of h in time. Black and white colour map, with power spectral density above and below −60 dB reported in black and white, respectively. As expected, there is significant power spectral density only at zero frequency. k, Typical radio-frequency spectrum from j, at 20 min.