Tunable single notch microwave photonic filter based on delay lines

摘要

We demonstrate a microwave photonic single notch filter based on a two-tap delay line structure. Obviously different from previous two-tap filters with periodic notch response, our modified two-tap filter can realize microwave photonic filter (MPF) with single notch response. In the proposed two-tap delay line structure, one tap acts as a phase tunable allpass MPF, while the other tap performs as a frequency tunable bandpass MPF. A single notch MPF is realized by selecting one period of the conventional two-tap filter response. The single notch frequency is tunable over a broad bandwidth by properly setting the phase of the allpass MPF as well as the center frequency of the bandpass MPF. The proposed MPF is theoretically analyzed and experimentally verified.