Analysis and Compensation of Third-Order Dispersion Induced RF Distortions in Highly Reconfigurable Microwave Photonic Filters

A scheme to perform high-quality-factor (Q) reconfigurable microwave photonic filtering with the optical third-order dispersion (TOD) induced radiofrequency (RF) distortions compensated is demonstrated. A detailed investigation of the TOD induced RF distortions is presented both theoretically and experimentally. By programming the optical spectrum in one arm of the Mach-Zehnder structure, the distortions can be completely eliminated, giving rise to ideal RF transfer function which can achieve very high Q factors. The experimentally demonstrated Q factors are 634 and 76 when the RF center is tuned to 18 GHz and the passband shape is configured to be sinc-shape and flat-top respectively, the highest values ever reported for a single-bandpass, complex-tap, and reconfigurable microwave photonic filter.