A Stopband and Passband Switchable Microwave Photonic Filter Based on Integrated Dual Ring Coupled Mach–Zehnder Interferometer

A stopband and passband switchable microwave photonic filter based on the integrated tunable dual ring coupled Mach-Zehnder interferometer has been demonstrated. By using the optical single sideband modulation, the switchable stopband and passband optical responses of the optical filter are one-to-one mapping to the RF spectra. The center frequency and bandwidth of the switchable microwave photonic filter are both reconfigurable. A frequency tuning range of 4-25 GHz is obtained, and the bandwidth tuning ranges of the passband and stopband MPFs are 4.54-9.72 GHz and 3.65-6.35 GHz, respectively. In addition, a RF rejection ratio about 20 dB is achieved. Compared with the switchable MPFs implemented by nonintegrated devices, the proposed switchable MPF provides a simple and low cost method to process radiofrequency signals.