Fig. 1. Schematic of down-conversion system

Fig. 2. Frequency spectrum processing of SBS effect. (a) Double-sideband modulation with suppressed carrier;(b) gain and loss spectra of pumping laser and SBS; (c) final spectrum after SBS effect

Fig. 3. Spectrum of double-sideband modulation with suppressed carrier

Fig. 4. Signal spectrum after SBS effect

Fig. 5. Frequency spectrum of intermediate frequency signal with frequency of 20 MHz

Fig. 6. Phase curve of IF intermediate frequency signal with frequency of 20 MHz

Fig. 7. Frequency spectrum of intermediate frequency signal with frequency of 30 MHz

Fig. 8. Frequency spectrum of intermediate frequency signal with frequency of 40 MHz