Low Index Cladding For Polymer Microring Resonator Waveguides

Polymeric materials are one option to realize photonic integrated circuits (PICs). Pure and hybrid polymer materials have garnered significant interest due to their distinctive properties, such as a simple, efficient, and scalable fabrication process as well as refractive index tuning [1]–[3]. Microring resonators (MRRs) fabricated in polymer waveguides have demonstrated groundbreaking applications in biosensing, medical diagnostics, food analysis, and environmental monitoring [1]–[4]. Additionally, they are emerging as miniaturized ultrasonic detectors for photoacoustic imaging [5], [6]. However, polymers face challenges in achieving both low and high refractive indices, which are crucial for versatile applications. This limitation highlights the need to improve the refractive index contrast between the core and cladding in various applications. Recent advancements in virtual - and augmented reality (VR/AR) devices have expanded the range of available polymer solutions. For example, low-refractive-index polymers have been used for lower cladding layers [7], while UV-curable hybrid organic-inorganic materials have been employed as waveguide materials.