High-Power Picosecond Pulsed Kerr Soliton Microcombs

Dissipative Kerr solitons in optical microresonators offer unparalleled platforms for ultralow-noise, high-repetition rate frequency comb generation with a compact form and driven by a continuous-wave laser. However, despite their attractive properties suited for practical applications, fundamental limitations regarding their output power and conversion efficiency still remain crucial problems that must be overcome. Here we discover unexplored operation regimes of Kerr soliton microcombs yielding high power and a picosecond pulse width by exploiting the strong mode interaction in birefringent crystalline microresonators. We demonstrate experimentally single-soliton microcombs with average powers of up to 24 and 38 mW as well as an improved conversion efficiency with a double-digit percentage and a microwave soliton repetition rate as low as 15.5 GHz. The observations are in agreement with numerical analyses based on the Lugiato-Lefever equation. The presented results not only facilitate novel applications and an architecture based on microresonator frequency combs, but also contribute to a further understanding of soliton physics.