A Simple and Tunable Single-Bandpass Microwave Photonic Filter of Adjustable Shape

A simple and tunable single-bandpass microwave photonic filter of adjustable shape is proposed and experimentally demonstrated. The filter is based on multiple sources (spectrum-sliced by a Mach-Zehnder interferometer) and two cascaded incoherent optical structures, namely, a dispersion medium of 50-km single-mode fiber and a fiber ring delay line. In the experimental range from 1.0 to 3.8 GHz, a discretely tunable single-bandpass filter with a high
Q
-factor or a flat-top response is achieved by carefully matching the transfer functions of the two individual optical structures.