Accurately extracting silicon waveguide dimensions from a single high-order Mach-Zehnder Interferometer

We experimentally demonstrate a new methodology for the extraction of dimensions from silicon-on-insulator (SOI) strip waveguides manufactured in IMEC's iSiPP50G silicon photonics platform. The effective index (n_eff) and group index (n_g) of the waveguide are determined from the spectral data of a single high-order Mach-Zehnder Interferometer (MZI). In this study, we introduce an innovative mapping model that effectively relates the geometric dimensions of the SOI waveguide to its n_eff and n_g, thereby enhancing mapping accuracy and reducing model complexity. Furthermore, we will elucidate the feasibility and constraints for extracting n_eff and n_g through the optical transmission measurement of only a single high-order MZI. Our analysis also addresses the parameter extraction errors that have a significant impact on the results, which have not been previously discussed in the literature.