Effect of gamma radiation on variously fabricated FBGs to verify the applicability of optical fiber sensors in radioactive environments

Fiber Bragg gratings (FBGs) are essential for sensing applications in extreme environments, such as those affected by gamma radiation. This paper compares the performance of FBGs fabricated using femtosecond (fs) and ultraviolet (UV) lasers under high-dose gamma irradiation. Three FBGs were subjected to controlled gamma radiation to assess their stability and potential for sensing under such conditions. The results reveal that fs- FBGs exhibit superior resistance to radiation-induced wavelength shifts, with only minor variations attributed to temperature fluctuations. In contrast, UV-laser-fabricated FBGs showed significant wavelength drift, rendering them less suitable for use in gamma-ray environments. These findings underscore the potential of fs-FBGs for precise sensing of temperature, pressure, and strain in high-radiation environments, such as nuclear reactors.