Reducing disorder-induced backscattering in photonic crystal waveguides through inverse design
Phys. Rev. A 113, 023515 – Published 11 February, 2026
DOI: https://doi.org/10.1103/pqdc-34mp
Abstract
Photonic crystal waveguides (PCWs) allow for the engineering of photonic waveguide modes and band structures to control the flow of light and enhance light-matter interactions within the waveguide. They have shown potential for enhancing optical nonlinearities, single photon emissions from quantum dots, as well as for use in optical buffers due to their ability to confine fields on-chip and produce slow-light modes. While these features are promising for applications in nanophotonics, PCWs are prone to high scattering losses due to disorder-induced backscattering, which has remained a major challenge across various waveguide designs for decades. By combining a fast mode solving approach with physics-based scattering formulas and inverse design, we show how backscattering losses can be significantly reduced, even when working at the same group index. We demonstrate substantial improvements for both W1-like waveguide modes and topological waveguide modes. Our general methodology is fully three-dimensional and can be used to design new PCWs optimized for a variety of performance metrics.
