Microwave photonic filter with arbitrary tap profile generated by polarization control in a LiNbO3 phase modulator

We propose a microwave photonic filter (MPF) of which both the tap weight and the polarity are adjusted by varying the polarization direction of the input lightwave. Arbitrary tap profiles can be generated simply by polarization control of the multi-wavelength source. Theoretical analyses are presented. A 7-tap MPF are implemented experimentally, and the passband can be configured to be flat-top or with zero baseband response. The optical power into photo detector keeps constant during filter reconfiguration, which leads to more stable operation.