Fig. 1. Schematic diagram of spectrum at different points

Fig. 2. Schematic diagram of frequency domain theoretical analysis of microwave mode-locking

Fig. 3. Diagram of experimental device

Fig. 4. Spectra filtered by stimulated Brillouin scattering

Fig. 5. Microwave signal with cavity length of 1 km

Fig. 6. Microwave frequency combs obtained by photoelectric oscillators with different cavity lengths

Fig. 7. Center frequency tunability of microwave frequency comb signal

Fig. 8. Spectrum of SBS-AML-OEO at different center frequencies

Fig. 9. Frequency stability of SBS-AML-OEO over 30 min