Multi-tap photonic microwave filter based on two-pump fiber optical parametric amplifier

We propose and demonstrate a novel approach to implement a multi-tap photonic microwave filter. By using a two-pump fiber optical parametric amplifier (OPA), the number of signal laser sources needed is only half of the number of filter taps because new frequency components idlers are generated. Moreover, the free spectral range (FSR) of the proposed filter can be changed by simply changing the wavelength spacing between the signals. In our experiment, an 8-tap photonic microwave filter has been demonstrated using 4 signal laser sources, with FSR tuning range from 1.18 GHz to 2 GHz which shows consistency between experimental and theoretical results.