Damage and recovery of fiber Bragg grating under radiation environment**Project supported by the Project for the State Key Laboratory of Optoelectronic Materials and Technologies of China (Grant No. 09010-32031708) and the Project for Zhuhai Key Laboratory of Center for Space Technology of China (Grant No. 71000-42080001).

Abstract

To develop the application of fiber Bragg gratings as temperature and strain sensors in space environments, it is necessary to understand the effect of high-energy radiation on the performance of the fiber Bragg grating. We performed an experiment involving Co60-γ ionizing irradiation with a total dose of 1.01 × 106 rad on two Ge-doped single-mode fiber Bragg gratings with central wavelengths of 825 and 835 nm, respectively. We found that, with the increase of radiation dose, the redshift of the peak wavelength of the reflection spectrum of the fiber Bragg gratings indicated the increase of the refractive index and the number of color centers. After irradiation, the refractive index decreased with the decreasing number of color centers. We analyzed the influence of ionizing irradiation on the transmission performance of the fiber Bragg gratings using a color-center model, which explained the experimental results. The proposed model was used to determine the creation rate and annihilation rates of the color center, which are foundational data for using the fiber Bragg gratings in space applications.