On-chip silicon photonic integrated frequency-tunable bandpass microwave photonic filter.

An on-chip frequency-tunable bandpass microwave photonic filter (MPF) implemented on a silicon photonic platform is reported. The on-chip MPF consists of a high-speed phase modulator (PM), a thermally tunable high-Q micro-disk resonator (MDR), and a high-speed photodetector (PD). The filtering function of the MPF is realized based on phase modulation and phase modulation to intensity modulation conversion, to translate the spectral response of the MDR in the optical domain to the spectral response of the MPF in the microwave domain. The tunability of the MPF is realized by thermally tuning the MDR. The proposed on-chip bandpass MPF is fabricated and characterized. An MPF with a passband of 1.93 GHz and a tunable range from 3 to 10 GHz is demonstrated. The power consumption, the insertion loss, and the bandwidth over the entire tunable range are studied. This successful implementation of an MPF marks a significant step forward in the full integration of microwave photonic systems on a single chip.