Periodic Topology Optimization-Based Inverse Design of Slow-Light in Silicon Nitride One-Dimensional Grating Waveguides

Devices engineered for slowing light, utilizing one-dimensional grating waveguides and fabricated from silicon nitride, often necessitate large footprints to secure the required delay, a consequence of the material's inherently low refractive index. Our approach employs a genetic algorithm to optimize 100x100nm<<^>>2 etchings on a predetermined grating waveguide topology, allowing for either the selective guidance of peak pulse intensity of the output or the augmentation of true time delay within the identical unit length. Within the chosen predetermined topology, the optimal configuration was identified based on the properties of the signal excitation in the time domain. This approach significantly facilitates the application-specific selection of peak intensity decay rate and time delay behavior within a 1D grating waveguide system.