A novel wavelength detection technique of overlapping spectra in the serial WDM FBG sensor network

•We study the serial WDM FBG sensor network wavelength detection problem when the spectra overlap.•The transfer matrix method is used to construct the optimization function.•We propose an appropriative improved differential evolution algorithm to solve the optimization model.•The wavelength detection error is typically smaller than 0.2 pm.

Wavelength detection problem is addressed in a serial wavelength division multiplexing (WDM) fiber Bragg grating (FBG) sensor network, where the spectra of the FBGs are partially or fully overlapped. Specifically, an optimization model utilizing the transfer matrix method to analyze the reflection spectra is presented. The search space of this problem indicates that the optimal solution and the sub-optimal solution are completely symmetric. Considering the peculiarity of the problem, an improved differential evolution (DE) algorithm, named Swap-DE, is used to calculate the Bragg wavelengths. Experimental results show that the wavelength detection error is typically smaller than 0.2 pm.