Compact Silicon Waveguide Mode Converter Employing Dielectric Metasurface Structure

Abstract Mode converters are key components in on‐chip mode‐division multiplexing systems. A compact silicon waveguide mode converter is proposed and demonstrated using all‐dielectric metasurface structure with a tilted subwavelength periodic perturbation. The proposed waveguide mode converter can be scaled to realize arbitrary waveguide mode conversion. As examples, two waveguide mode converters are experimentally demonstrated on a silicon‐on‐insulator wafer, which can convert the TE 0 mode to the TE 1 mode and the TE 2 mode with coupling lengths of 5.75 and 6.736 µm, respectively. The conversion losses of <1 dB and crosstalk values of <−10 dB are achieved for both the TE 0 ‐to‐TE 1 and the TE 0 ‐to‐TE 2 mode converters.