Enhancement of the measurement range of FBG sensors in a WDM network using a minimum variance shift technique coupled with amplitude-wavelength dual coding

The measurement range of fiber Bragg grating (FBG) sensors within a wavelength division multiplexing (WDM) network was extended by the use of a combination of amplitude-wavelength dual coding and a minimum variance shift technique. To increase the multiplexing capacity, the width of the spectral slice allocated to each sensor should be reduced because of the limited total available source spectrum. The crosstalk between sensors could be minimized even when the spectrums of FBG within network were partially or fully overlapped.