Brillouin-assisted frequency-tuning-range-extended and passband-selected microwave photonic filter based on DPol-DPMZM

A frequency-tuning-range-extended and passband-selected microwave photonic filter (MPF) based on dual-polarization dual-parallel Mach-Zehnder modulator (DPol-DPMZM) is proposed and experimentally demonstrated. The upper DPMZM is biased to serve as an equivalent phase modulator, while the lower DPMZM is selectively biased to generate different modulated sideband for pump wave, and then different passband frequency response is selectively realized based on the stimulated Brillouin scattering effect. By using the upper and lower sidebands of carrier-suppression single sideband for pump wave successively, the frequency tuning range of the single-passband MPF can be extended by a value of Brillouin frequency shift, comparing with only one sideband is used. A single-passband MPF with a frequency tuning range of 1.43-19.43 GHz is experimentally obtained, while only a single-tone RF with a frequency range of DC-9 GHz is used. The double-passband MPF with equal passband magnitude and frequency interval tuned is also experimentally achieved.