Platform-Independent Optimization of Pump Power Threshold for Microcomb Generation

Kerr optical frequency combs have found various applications in science and technology, minimizing their pump power has become an important area of research. These are generated using a wide variety platforms, with size ranging from micrometers to millimeters, quality factors millions billions. It is therefore not trivial assess the requirements for comb generation when they such large diversity terms resonator properties configurations. We propose suitably normalized threshold as metric optimize independently platform. This method allows one evaluate minimum solely based on bare resonator, dispersion, detuning or coupling considerations. In order confirm validity this approach, we experimentally demonstrate millimeter-size magnesium fluoride whispering-gallery mode only 1.2 mW, which lowest powers reported date mm-size resonator.