Thermal tuning behavior and robust control of a single-soliton microcomb with a modulated sideband.

A chip-scaled single-soliton microcomb source promises wide applications in various fields. We demonstrate the deterministic single-soliton generation from both pump forward and backward tunings via sideband thermal compensation. The total soliton existing range (SER) is effectively expanded due to the thermal-lock effect and remains nearly the same regardless of the soliton states. Besides, we prove the degeneration of the forward-tuning SER, accompanied by the decrease in the soliton number. This scheme remains robust against a significant pump wavelength chirp, sustaining a free-running single soliton for over 9 h with line power fluctuations below 0.6 dB.