Optimized weak fiber Bragg array interrogation system based on adaptive gain and polynomial fitting method

An optimized WFBGA interrogation system based on an adaptive gain control and polynomial fitting algorithm is demonstrated, achieving the demodulation of WFBGA containing 1000 WFBGs with a reflectivity of -40 dB and a spacing of 1.5 m. To avoid the trade-off between the saturation of frontend WFBGs and the low amplitude of backend WFBGs in the fixed gain, an adaptive gain control method is adopted to maintain the reflection amplitude of each WFBG at the preset threshold, i.e., -35 and -34 dBm, by independently and dynamically adjusting the driving current of each WFBG through address scanning. Compared with the centroid and Gaussian fitting methods, the polynomial method exhibited superior stability, i.e., minimal wavelength fluctuation, and excellent consistency, i.e., minimal wavelength error.