True-time delay and mode-matching in Archimedean spiral silicon photonic waveguides
Year: 2025
Type: article
Abstract: We report a comprehensive analysis and design optimization of true-time delay (TTD) photonic waveguides using compact Archimedean spiral geometries, with a focus on low-loss silicon nitride (Si3N4) and silicon-on-insulator (SOI) platforms. Using a combination of finite element and finite-difference time-domain simulations at 1550 nm, we evaluated the propagation characteristics, mode-matching behavior, and bending losses of various waveguide designs. Our results demonstrate that Si3N4 rectangular waveguides exhibit superior performance for long optical paths, achieving minimal radiation and scattering losses, whereas SOI is more suitable for compact integration. We further investigated curvature-engineered bends (Euler, Bézier, and circular) and identified Quartic Bézier bends as optimal for tight-radius, low-loss guiding. By minimizing crosstalk through tailored waveguide gaps and carefully engineered S-bend transitions, we present a scalable low-loss TTD architecture. These findings offer critical insights for integrating ultralow-loss, material-efficient delay lines into photonic circuits for applications in signal processing, LiDAR, phased array antennas, and neuromorphic computing.
Source: Engineering Research Express
Authors: Ahmad Murad, Alina Karabchevsky
Institution: Ben-Gurion University of the Negev
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,400
OpenAlex ID: W4414005880