Impact of Pulse Chirp and Desynchronization on Chip-Based Pulse-Driven Soliton Microcombs

Soliton microcombs, a pivotal technology supporting various cutting-edge applications from metrology to communications, can be efficiently generated through the pulsed driving of Kerr microresonators. However, the mechanism that influences driving pulses on soliton generation has not been comprehensively explored. Here, we demonstrate a chip-based pulse-driven soliton comb with the minimal on-chip pump power of 1.70 mW at 25 GHz repetition rate and study the impact of pulse chirp numerically and experimentally. By varying pulse chirp and desynchronization, a wide locking range of 900 kHz can be reached with fixed cavity parameters, ensuring efficient attractive single-soliton operation. This work reveals that pulse pumping introduces more degrees of freedom and rich novel dynamics into soliton generation and could facilitate the development of efficient on-chip soliton microcomb systems.