Coherence-free microwave photonic notch filter with a wide passband and a narrow notch

A new microwave photonic notch filter structure that realises coherence-free, narrow notch width, and wide passband operation, is presented. It is based on a WDM technique with a double-pass modulation approach incorporating sequentially spaced reflectors that provide the appropriate time delays for the remodulations. Experimental results are presented which demonstrate a coherence-free microwave photonic filter that exhibits a narrow-notch, a wide passband, and no phase noise limitations, simultaneously.