Lossy mode resonance in photonic integrated circuits

• Lossy mode resonance phenomenon is achievable in integrated waveguides made of various polymers such as OrmoClear, OrmoCore and SU-8. • Lossy mode resonance integrated sensors can achieve sensing capabilities comparable to alternative configurations. • Utilizing UV exposure of the photoresist from the bottom of the substrate with an on-chip aluminum mask leads to the fabrication of thick waveguides with a more rectangular cross-sectional shape. In recent years, the promising phenomenon known as lossy mode resonance (LMR) has garnered significant attention in sensing applications. While existing literature in the field of LMR focuses on optical fiber systems and planar waveguides due to their simplicity, there is an absence of research on systems based on photonic integrated circuits (PICs). This article aims to demonstrate, for the first time, the generation of LMR in PICs with sensitivity and a figure of merit (FOM) comparable to that of optical fibers and planar waveguides. Additionally, the article offers a comparison of various polymer materials such as OrmoClear, OrmoCore and SU-8 for integrated waveguides fabrication. To summarize, the main novelty of the article is the demonstration of the LMR phenomenon in integrated chips and the comparison of different polymers commonly used in photonics to fabricate these chips. Moreover, the authors present a novel fabrication workflow for thick polymer waveguides. Finally, the study compares the experimental results obtained with simulations conducted using the finite element method (FEM) in COMSOL Multiphysics environment.