  We report the first demonstration of thermally controlled soliton modelocked
frequency comb generation in microresonators. By controlling the electric
current through heaters integrated with silicon nitride microresonators, we
demonstrate a systematic and repeatable pathway to single- and multi-soliton
modelocked states without adjusting the pump laser wavelength. Such an approach
could greatly simplify the generation of modelocked frequency combs and
facilitate applications such as chip-based dual-comb spectroscopy.
