Switchable and tunable microwave photonic filter based on reflective semiconductor optical amplifier

A microwave photonic filter, which can be switched between a high-Q bandpass filter and a notch filter, is proposed and experimentally demonstrated. It is based on a recirculating delay line loop with a reflective semiconductor optical amplifier, and negative taps are generated employing wavelength conversion. The filter can be also tuned by adjusting an optical variable delay line. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:198–201, 2014