A novel switchable microwave photonic filter

A novel switchable microwave photonic filter (MPF) based on a second-order Lyot loop and an optical phase modulator (PM) is presented and experimentally demonstrated. A broadband light emitted from a broadband optical source (BOS) is sliced by a second-order Lyot loop which acts as a spectrum slicer, then, is modulated by an optical PM and delayed by a dispersive medium. By doing this, a switchable microwave photonic filter free the baseband resonance is achieved, the radio frequency (RF) responses show three different passband states, which are single passband state, dual-passband state and triple-passband state, respectively. The proposed switchable MPF exhibits a high rejection ratio, which is larger than 30 dB.