High energy efficiency soliton microcomb generation in high coupling strength, large mode volume, and ultra-high-Q micro-cavity

The nonlinear physics dynamics of temporal dissipative solitons in a microcavity hinder them from attaining high power from pump lasers with a typical nonlinear energy conversion efficiency of less than 1%. Here, we experimentally demonstrate a straightforward method for improving the output power of soliton combs using a silica microrod cavity with high coupling strength, large mode volume, and high-Q factor, resulting in a low-repetition-rate dissipative soliton ( ∼ 21 GHz) with an energy conversion efficiency exceeding 20%. Furthermore, by generating an ∼ 105 GHz 5 × FSR (free spectral range) soliton crystal comb in the microcavity, the energy conversion efficiency can be further increased up to 56%.