Octave-Spanning Soliton Microcomb with Over 50% Conversion Efficiency Enabled by Strong Mode Coupling

Dissipative Kerr solitons (DKS), which provide coherent and stable frequency combs, have emerged as a powerful tool for a wide range of applications in metrology, spectroscopy, telecommunications [1]. However, one of the major challenges hindering their practical deployment is the inherently low pump-to-comb conversion efficiency [2], [3], which is typically restricted to only a few percent. Recent advances have introduced promising strategies to enhance conversion efficiency in single-soliton states, including new pumping schemes such as pulsed pumping [4] and novel cavity designs like photonic molecules [5]. Nevertheless, existing high-efficiency demonstrations have thus far been constrained by limited optical bandwidths, falling short of the broad spectral coverage required for demanding applications such as self-referencing and broadband spectroscopy.