Fig. 1. Schematic of FWM and SBS in microcavity. (a) Diagram of SBS energy levels; (b) FWM energy level diagram; (c) Brillouin laser generation process; (d) schematic of degenerate FWM and non-degenerate FWM; (e) schematic of Brillouin-coupled FWM in microcavity

Fig. 2. Schematic of modulation instability in the microcavity, Brillouin gain, and Raman gain

Fig. 3. Transmission spectrun of CaF₂ crystal microcavity and microcavity microscopic photo. (a) Transmission spectrum of CaF₂ crystal microcavity; (b) Lorentz fitting line; (c) microscopic photograph of CaF₂ crystal microcavity

Fig. 4. Schematic of nonlinear experimental device based on CaF₂ crystal microcavity and forward direction and opposite direction transmission spectra under high power

Fig. 5. SBS effect. (a) First-order Brillouin signal; (b) cascade Brillouin signal; (c) first-order Brillouin-coupled comb signal

Fig. 6. Brillouin-coupled four wave mixing signal. (a)(b) First-order Brillouin light frequency comb with double FSR; (c)(d) first-order Brillouin light frequency comb with single FSR

Fig. 7. Result of stimulated Raman experiments. (a) First-order Raman laser; (b) first-order Raman comb; (c) broadband frequency comb; (d) local amplification on the left side of the broadband frequency comb; (e) first-order Raman comb enlargement

Fig. 8. Optical frequency comb experimental results. (a) Optical frequency comb in the wavelength range of 900 nm, illustration is a luminescence photo of CaF₂ crystal microcavity; (b) local magnification of the central wavelength of 850 nm; (c) local enlargement around the pump light; (d) local magnification of first-order Raman comb