Microwave photonic filter with a continuously tunable central frequency using an SOI high-Q microdisk resonator

Utilizing a high-Q microdisk resonator (MDR) on a single silicon-on-insulator (SOI) chip, a compact microwave photonic filter (MPF) with a continuously tunable central frequency is proposed and experimentally demonstrated. Assisted by the optical single side-band (OSSB) modulation, the optical frequency response of the MDR is mapped to the microwave frequency response to form an MPF with a continuously tunable central frequency and a narrow 3-dB bandwidth. In the experiment, using an MDR with a compact size of 20×20 μ² and a high Q factor of 1.07×10⁵, we obtain a compact MPF with a high rejection ratio of about 40 dB, a 3-dB bandwidth of about 2 GHz, and a frequency tuning range larger than 12 GHz. Our approach may allow the implementation of very compact, low-cost, low-consumption, and integrated notch MPF in a silicon chip.