Recent Advances in PDMS Optical Waveguides: Properties, Fabrication, and Applications

Poly(dimethylsiloxane) (PDMS) has emerged as a promising polymer for fabricating optical waveguides. Its optical transparency, stretchability, flexibility, biocompatibility, and facile processing are a complement to common optical materials that are more brittle and stiff such as fused silica, polystyrene (PS), and poly(methyl methacrylate) (PMMA). Although PDMS is not a new material, with its first synthesis dating back to the early twentieth century, recent decades have seen an increased effort to expand its use in optical waveguides beyond conventional rubber applications. This review compiles established concepts and new advancements in PDMS science to shed light on limitations and new opportunities to better harness PDMS' potential for optical waveguiding. With the materials science tetrahedron in mind (structure, properties, processing, and performance), this review explores the state-of-the-art in PDMS waveguide technology and exposes relevant basic concepts pertaining to its physicochemical properties. The goal is to equip the photonics community with knowledge to further expand PDMS waveguide technology. The review covers three main topics: PDMS' key properties (chemical, optical, thermal, and mechanical, besides biological and environmental aspects); PDMS waveguide fabrication techniques (processing, refractive index tuning, and post-processing); and its applications. The review concludes with a discussion of current challenges and future prospects.