Silicon nanophotonic waveguides using rare earth ion diffusion technology

The paper presents the design of a silicon-based nanophotonic active optical waveguide, in which rare earth ions are diffused into enhanced passive waveguides fabricated on a silicon-on-insulator (SOI) platform. Since erbium (Er)-doped waveguides can provide a higher gain coefficient in an Al₂O₃ waveguide cladding, a novel approach is proposed to further enhance the gain of an erbium-doped waveguide amplifier (EDWA). This method utilizes a subwavelength waveguide structure, where a film surrounds the segmented SOI waveguide. The proposed approach enables improved gain performance in widely used SOI waveguides by leveraging the advantages of an Er-doped Al₂O₃ layer.