A novel multiplexed fiber Bragg grating sensor with application in structural health monitoring

Abstract

The use of fiber Bragg gratings (FBGs) on a single fiber for analyzing the strain in two dimensions is presented. The effects of the simultaneous transversal and longitudinal force on an FBG sensor is analyzed and its perturbed reflected spectrum is modeled by introducing the change of the refractive indecies and grating period along the fiber to the transfer matrix formulation method (‘measured’ spectrum). Furthermore, the use of genetic algorithm for reconstruction of nonuniform applied transverse forces from the ‘measured’ spectrum is presented. The genetic algorithm requires only the measured spectra information and the refractive index distribution is encoded along the Bragg grating into the genes. The presented method is verified through the numerical examples and the results show that our methodology can effectively represent and model the applied transverse force profile (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Design of code division multiple access filters based on sampled fiber Bragg grating by using global optimization algorithms

“…For example, Navruz et al use a Simulated Annealing approach to optimize the phase profile of a Multichannel SFBG (Navruz and Guler 2007), whereas Ngo et al consider a Tabu Search algorithm to design the index modulation function of a pass-band SFBG (Ngo et al 2007). However, one of the most used method to solve SFBG design problems are GAs as in the works presented in Cheng et al (2008), Etezad et al (2011), Skaar and Risvik (1998) and Tremblay et al (2005), where various SFBG parameters (such as the fiber length or the refractive index modulation length) are optimized to obtain pass-band filters.…”

“…To solve this inverse problem we consider global optimization algorithms (Skaar and Risvik 1998). Currently, one of the most used optimization methods in this domain are genetic algorithms (GA) (Etezad et al 2011;Cheng et al 2008;Tremblay et al 2005).…”