Palladium-based optical fiber Bragg grating hydrogen sensors: A comprehensive review

In the field of hydrogen sensing and detection, optical fiber sensors are attractive due to their microminiature size and good performance in intrinsic safety, anti-electromagnetic interference, corrosion resistance, and radiation resistance. Specially, fiber Bragg grating (FBG) sensors consisting of fiber Bragg grating and Pd-based materials attract much attention because they are easy to distribute measurements. Pd-based fiber Bragg grating sensors have demonstrated great potential in the past three decades. This paper gives a comprehensive overview of the Pd-based fiber Bragg grating hydrogen sensor. The principle of this technology is expounded, and the research progress from 1999 to 2023 is traced back. Then the influence factors of fiber micro-nano structure and Pd-based hydrogen-sensitive materials on the performance of the sensor are discussed in depth. Finally, obstacles encountered during the research process are discussed, and challenges and opportunities in the development of fiber Bragg grating hydrogen sensors are highlighted.