Microwave photonic filter with negative coefficients based on counter-phase modulation using a single electro-optic phase modulator

A simple photonic approach is proposed for the implementation of a reconfigurable multi-tap microwave filter with negative coefficients. In this scheme, a dual-optical-input intensity modulation module which can perform counter-phase modulation is constructed using a single electro-optic phase modulator. Two inter-complementary microwave signals are experimentally obtained for verification of the function of counter-phase modulation. A reconfigurable four-tap microwave filter with two negative coefficients is implemented by experiment.