Analyzing the evanescent field ratio of ridge waveguide based on different material platforms for sensing applications

In this study, a comprehensive numerical investigation focusing on a ridge waveguide composed of various material platforms is undertaken, including silicon-on-insulator (SOI), silicon nitride (SiN), and SU-8 polymer. In the realm of photonic sensing devices, the evanescent field assumes paramount significance in facilitating light-matter interactions. The primary objective of this study is to furnish a comparative analysis discerning the suitability of these material platforms for sensing applications. The findings reveal distinct characteristics among the different material platforms. SOI emerges as a standout contender, exhibiting an augmented evanescent field ratio (EFR) that substantially enhances light-matter interaction. Following closely, SiN-based waveguides demonstrate commendable performance in this regard. Conversely, SU-8 polymer waveguides, characterized by larger dimensions, present limitations in evanescent field confinement, resulting in the lowest sensitivity among the materials investigated. Hence, the selection of the appropriate material platform and waveguide type emerges as a critical consideration in the design phase of photonic sensors. This decision significantly influences the sensor's performance and efficacy in real-world applications.