Inverse Designed SU8-on-Insulator Platform for Polymer Waveguide Photonics

In this letter, we propose, for the first time, a three-dimensional gradient inverse design framework tailored for bound shape optimization on the SU8-on-Insulator (SUOI) platform, enabling efficient exploration of a large parameter space. Performance tolerance analysis through simulation confirms the robustness of the optimized devices against practical fabrication variations. Based on this algorithm, we experimentally demonstrate three key devices for SU-8 polymer waveguide photonics, a waveguide crossing, a Y-branch power splitter, and a compact waveguide bend, each exhibiting low insertion losses, tiny footprints, a wide bandwidth from 1450nm to 1620nm, and excellent agreement between simulation and experimental results. The polymer waveguide devices and the algorithm framework represent a key advancement toward the various device capabilities required for future SUOI photonics, providing solutions for SU8-based photonics integration systems and sensing platforms.