Spectra of fiber Bragg grating in nuclear environment

Dense wavelength division multiplexing (DWDM) technology is a promising way for high transmission-rate demand in the ever complex Earth Observation satellites and space station. However, fiber Bragg grating (FBG) filters used in DWDM systems may fail to check out the correct wavelength affected by cosmic rays. In order to analyze the spectra characteristics of FBGs in gamma radiation environment, we simulate the wavelength shift by controlling gamma-induced effective index change. The effect caused by gamma radiation is taken as a perturbation to the effective refractive index of the guided mode of interest. Coupled-mode theory is involved to establish the model describing the effect of gamma radiation on Bragg wavelength shift. The results show that the gamma-induced effective index change has good linearity with the change of Bragg wavelength. Meanwhile, the bandwidth of the reflection spectra broadens with the increased dose of gamma irradiation.