Tunable dual-passband microwave photonic filter based on stimulated brillouin scattering

The invention discloses a tunable dual-passband microwave photonic filter based on stimulated brillouin scattering. The filter conducts closed-loop control on an electro-optical modulator through a bias feedback control module, so that the electro-optical modulator outputs stable dual-passband modulation signals suppressed by narrow waves, carrier suppression dual-passband modulation optical signals output by the electro-optical modulator serve as a pumping source of an SBS, and accordingly two passbands are formed on filter responses. The designed filter achieves amplitude responses of the dual-passband filter according to Stokes gain and anti-Stokes loss. The filter can achieve the narrow bandwidth of 20.1 MHz, can achieve tuning in the range of 1.8 GHz-20 GHz, and obtains the stop-band suppression rate over 35 dB.