Passband-Controlled Cascaded Microwave Photonic Filter Based on Refletive Fiber Mach-Zehnder Interferometer

An approach to implement passband-controlled cascaded microwave photonic filter (MPF) based on broadband optical source (BOS) and reflective fiber Mach-Zehnder interferometer is proposed and experimentally demonstrated. The sliced BOS is used as multiple light sources, and a single-mode fiber is used as the dispersion medium. By changing the polarization controllers, the left-passband, right-passband and dual-passband states of the MPF can be separately achieved. The center frequency of the passband can be tuned by changing the optical variable delay line. By cascading a fiber ring, the 3 dB bandwidth of the cascaded MPF can be narrowed, compared to that without cascading the fiber ring.