The synthesis of multiple parameters of arbitrary FBGs via a genetic algorithm and two thermally modulated intensity spectra

This paper describes the use of a genetic algorithm and two thermally modulated fiber Bragg grating (FBG) reflection intensity spectra to perform the inverse extraction of multiple physical parameters of arbitrary FBGs, including the grating period, grating position, grating length, chirped direction, and refractive-index modulation. The developed numerical approach is applied to synthesize the parameters of uniform and chirped FBGs. The experimental results confirm the ability of the proposed method to recover the grating period, grating length, grating position, refractive-index modulation depth, and apodize factor of a 10-mm-length uniform FBG. The proposed method is suitable for fiber communication applications and smart structure-monitoring systems.