Review of Fiber Optic Sensing Technologies for Leak Detection in Hydrogen Energy Storage and Transport Equipment

Hydrogen, as a clean and efficient secondary energy source, has become a key pillar in the global transition toward carbon neutrality. However, its low molecular weight, wide flammability range, and high diffusivity make leak detection during storage and transportation a major safety challenge. In recent years, optical fiber sensing technologies have emerged as powerful tools for real-time monitoring of hydrogen leakage. Compared with traditional electrical sensors, optical fiber sensors exhibit strong resistance to electromagnetic interference, high sensitivity, compact structure, and capability for distributed and long-distance monitoring. This paper reviews the principles, materials, and applications of fiber optic sensing technologies for hydrogen leak detection. The changes in environmental parameters caused by leakage, including concentration, acoustic, and thermal effects, are first analyzed. The development of hydrogen-sensitive materials, such as metal-based and metal-oxide films, is then summarized. Subsequently, representative sensing methods—including Distributed Acoustic Sensing (DAS), Distributed Temperature Sensing (DTS), and Fiber Bragg Gratings (FBG)—are reviewed. Furthermore, sensing applications in hydrogen storage tanks and pipelines are discussed, with particular emphasis on vibration and temperature monitoring. Finally, current challenges, such as cross-sensitivity, environmental noise, and data interpretation, are highlighted, and an outlook on the integration of optical sensing with artificial intelligence for intelligent hydrogen safety monitoring and maintenance is provided.