CMOS compatible athermal silicon photonic filters based on hydrogenated amorphous silicon.

We report for the first time, wavelength filters with reduced thermal sensitivity, based on a combination of crystalline silicon and hydrogenated amorphous silicon (a-Si:H) waveguides, integrated on the same silicon on an insulator wafer through a Complementary Metal Oxide Semiconductor (CMOS) compatible process flow. To demonstrate the concept, we design and fabricate Mach Zehnder Interferometers (MZIs) and Arrayed Waveguide Gratings (AWGs) based on this approach, and we measure thermal drift <1[pm/°K] in MZIs and <10 [pm/°K] in AWGs at C band.