A tunable and reconfigurable microwave photonic filter based on a Raman fiber laser

A tunable and reconfigurable microwave photonic filter is demonstrated by employing a tunable Mach–Zehnder interferometer (MZI) and a wavelength-controllable Raman fiber laser. The free-spectral-range and spectral response of the microwave photonic filter are tuned and reconfigured by controlling the optical variable delay line in one arm of the MZI and the powers of the pump LDs. Experimental results are given to show the enhanced flexibility of the present microwave photonic filter.