A Tunable Single Passband Microwave Photonic Filter of Overcoming Fiber Dispersion Induced Amplitude Fading

A tunable single passband microwave photonic filter (MPF) of overcoming fiber dispersion induced amplitude fading of the microwave passband is proposed and demonstrated. The passband amplitude of the MPF can be kept invariant for different central frequencies. The scheme is realized based on a dual-drive Mach–Zehnder modulator (DDMZM) and a broadband optical source sliced by a delay interferometer. The DDMZM is single-electrode driven and the microwave signal is modulated onto the optical carrier with simultaneous phase and intensity modulation formats. The ratio of the two modulation formats can be controlled by adjusting the bias of DDMZM to compensate the dispersion-induced amplitude fading at any passband of the MPF. In the experiment, the proposed MPF can be tuned between 0 and 30 GHz and the rejection ratio exceeds 30 dB.