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.