Microresonator-Based Mode-Locked Laser with Tunable Pulse Repetition Rates

Mode-locking techniques are crucial for advancing laser applications, producing pulses with diverse duration and repetition rates. However, the generation of pulse trains with tunable repetition rates within a single laser cavity configuration remains unexplored. In our work, we demonstrate an actively mode-locked fiber-cavity laser incorporating a microring resonator to achieve pulse trains spanning nanosecond to picosecond timescales. Moreover, we show ultra-stable broadband microcombs with controllable center wavelengths for spectroscopy, metrology, and telecommunications applications.