Engineered Fiber Bragg Grating Sensors for High- Sensitivity Healthcare and Environmental Diagnostics

Abstract

The growing demands of modern healthcare and environmental safety call for sensing technologies that are rapid, highly sensitive, and deployable in real-world settings. This thesis addresses this challenge by establishing the Fiber Bragg Grating (FBG) as a versatile and powerful platform for next-generation optical sensors. Through innovative surface engineering and the development of novel transduction strategies, the intrinsic properties of FBGs have been strategically tailored to tackle a wide range of complex sensing problems. Within this unified framework, several distinct classes of sensors have been pioneered. A wearable biophysical sensor was designed to non-invasively monitor physiological motion for neurological assessment, translating subtle mechanical strain into precise optical signals. In the biochemical domain, ultrasensitive immunosensors for key cardiac biomarkers were realized by integrating advanced nanomaterials such as electrospun nanofibers and quantum dots to create high-surface-area interfaces that significantly enhance detection sensitivity. Extending beyond biomedical applications, a novel chemical sensing approach was demonstrated for environmental monitoring, relying on analyte-induced changes in the surrounding medium. Taken together, this body of work validates the FBG as a foundational platform for advanced diagnostics. By demonstrating its adaptability across biophysical, biochemical, and chemical sensing paradigms, the thesis contributes meaningfully to the field of optical sensing. The methodologies and principles developed here lay the groundwork for future point-of-care and in-situ devices with the potential to transform personalized medicine and environmental monitoring.