A Widely Tunable Photonic-Assisted Microwave Notch Filter with High Linearity Using a Dual-Parallel Mach–Zehnder Modulator

A widely tunable microwave photonic (MWP) notch filter with high linearity based on a dual-parallel Mach–Zehnder modulator (DPMZM) is proposed and experimentally demonstrated. The motivation of this work lies in the fact that the MWP notch filter previously reported has nonlinear distortions generally induced by the nonlinear property of electro-optic devices. In this scheme, even-order modulated sidebands at the DPMZM output are effectively suppressed by properly adjusting bias voltages of the DPMZM, which are the dominant factor to induce the nonlinear distortions into the MWP notch filter. The proposed scheme is theoretically analyzed and experimentally verified.