Frequency and Bandwidth Tunable Integrated Microwave Photonic Bandpass Filter

An integrated microwave photonic (MWP) filter in silicon-on-insulator technology with widely tunable and bandwidth reconfigurable flat-top passband functionality is presented. For this experimental demonstration, continuous bandwidth tuning from 5 to 10 GHz and central frequency positioning over a 70 GHz-wide range while preserving a large out-of-band power rejection of up to more than 40 dB are observed. The circuit exploits optical-to-RF mapping of the transfer function of a programmable photonic integrated optical filter through a scanning sideband provided by an on-chip silicon phase modulator, and additional control of the MWP filter RF gain for optimized performance. A high level of functional integration is demonstrated in a compact footprint of less than 2 mm2. Measurements conducted on a different photonic integrated filter design illustrate the potentiality for scaling down the bandwidth reconfigurability of the MWP filter in the 1-to-3 GHz range or below.