Extended Data Fig. 4: Examination of the simulated threshold between a 2-FSR comb to a 1-FSR comb at 0.115 GHz detuning.

a. Spectrum of the 2-FSR primary Kerr comb (red) and light in odd-numbered modes (green). b. Intracavity field in real space (rolling Turing) c. g⁽²⁾ correlations of the below threshold light. d. Eigen-spectrum of the comb showing that a non-oscillating supermode crosses threshold, and that the spectrum also has oscillating supermodes with less parametric gain. e. The squeezing RF spectrum, showing the single peak which correspond with the non-oscillating supermode that crosses threshold in d. f. The spectrum of the most squeezed state in the basis of cavity modes.