Tunable Single-Passband Microwave Photonic Filter with Enhanced Fineness

A tunable single-passband microwave photonic filter (MPF) with enhanced fineness is presented and demonstrated. The high-Q single-passband MPF is realized by cascading an optically injected semiconductor laser structure and an optoelectronic feedback resonator. In the proof-of-concept experiment, the center frequency of the MPF is tuned from 10 to 18 GHz by adjusting the optical injection parameters, and the 3-dB bandwidth is kept below 4.97 MHz. The proposed MPF offers tunability and high selectivity, and has potential applications in microwave communication systems and radar systems.