Integrated Microwave Photonic Filter on a Hybrid Silicon Platform

A hybrid silicon photonic integrated filter is proposed and demonstrated with a novel structure. This filter incorporates a ring resonator in one arm of a Mach–Zehnder interferometer making it possible to obtain a programmable filter response. The optical filter consists of a 5-mm-long delay loop made of low-loss silicon waveguides with integrated thermal modulators resulting in a 0.164-nm free spectral range with absolute phase tunability and gain elements that allow for the tuning of the filter
$Q$
factor. The microwave response of this integrated filter is measured and display tunability of 20 GHz.