Electrooptical Modulating Device Based on a CMOS-Compatible ${bm \alpha }$ -Si:H/ ${bm \alpha }$

In this paper, we report results on a field-effect-induced light modulation at λ = 1.55 μm in a high-index-contrast waveguide based on a multisilicon-on-insulator platform. The device is realized with the hydrogenated amorphous silicon (α-Si:H) technology, and it is suitable for monolithic integration in a CMOS IC. The device exploits the free-carrier optical absorption electrically induced in the semiconductor core waveguide. The amorphous silicon waveguiding layer contains several thin dielectric films of amorphous silicon carbonitride (α-SiCN) embedded along its thickness, thus highly enhancing the absorbing action of the modulator held in the on state.