A fiber optic sensor is an instrument that measures light from an LED (or other device) for detection purposes. These devices are most commonly used in factory automation environments. The amplifier contains "the brains". Our global manufacturing network for fiber optic sensors in Ayabe (Japan), Shanghai (China) and Nufringen (Germany) focuses on continuously optimising methods for small and large volume production, applying stringent quality control procedures, and expanding production portfolio and flexibility to. This study introduces a surface plasmon resonance-based fiber optic sensor (SPR) designed to accurately detect the refractive index of the environment. The sensor structure is based on a D-shaped fiber, with thin layers of gold, titanium dioxide and silver applied successively to its flat surface. Depending on the. Radiation absorption excites an orbital electron to a higher energy level. Heating the material enables the trapped states to interact with phonons and decay into lower-energy. In this study, a low-cost D-shape optical fiber sensor was fabricated using a multi-mode optical fiber, which means that light can pass through it in several different paths.