On-Chip Ultra-Compact Independently Tunable Dual-Passband Microwave Photonic Filter

We propose and experimentally demonstrate a silicon photonic independently tunable dual-passband microwave photonic filter (MPF) based on cascaded high-Q silicon micro-disk resonators (MDRs). The MPF integrates a micro-ring resonator modulator (MRM), two thermally tunable MDRs, and a Mach-Zehnder interferometer (MZI) on a single chip. The MRM and MDRs are placed in one arm of the MZI to map the spectral response via single-sideband modulation and carrier beating. Independent tunability of dual-passband center frequencies is achieved through voltage-controlled thermal actuation of micro-heaters monolithically integrated atop the MDRs. Experimental results demonstrate that the proposed MPF chip has dual passbands with bandwidths of 325 MHz and 425 MHz, extinction ratios of 23 dB and 25 dB, and a continuously tunable center frequency spanning 3-31 GHz. Featuring narrow passband, high extinction ratio, flexible frequency tunability and high integration degree, the proposed dual-passband MPF is suitable for multi-functional photonic-assisted microwave processing systems.