Optical Fiber Sensing Materials from a Green Chemistry Perspective: Principles, Applications, and a Sustainable Prospectus

Optical fiber sensing technology offers high sensitivity, electromagnetic immunity, and distributed sensing capabilities, with broad applications in environmental, biomedical, and industrial monitoring. However, its reliance on heavy-metal-doped glasses, rare-earth elements, and non-biodegradable polymers imposes significant environmental burdens across their lifecycle. This review establishes a systematic framework based on the Twelve Principles of Green Chemistry to assess and redesign optical fiber sensing materials, including silica, soft glass, and polymer matrices, as well as functional coatings, fluorescent probes, and plasmonic nanostructures. It highlights green alternatives such as sol-gel synthesis, bio-based polymers, carbon quantum dots, and biosynthesized nanoparticles. A multi-dimensional sustainability assessment, covering performance, environmental impact, economics, and social factors, identifies key challenges such as performance-environment trade-offs and scaling-up costs. Future pathways integrating AI-assisted design, additive manufacturing, modular systems, and policy support are proposed. The study argues that green attributes and high performance are synergistic, positioning green optical fiber sensing as essential for achieving circular economy goals and UN Sustainable Development Goals.