Performance Analysis of Apodized Fiber Bragg Gratings for Sensing Applications

Sensing performance of fiber Bragg grating in presence of various apodization functions are studied and compared. Using couple modes theory and matching the fields at various boundaries, the equation of reflectivity of fiber Bragg grating sensors are obtained. The sensors are optimized to get maximum reflectivity with narrow full width half maximum of the resonance peak. It is observed that all considered apodization functions suppress the sidelobes. The suppression of dominating sidelobe is maximum −141.29 dB for Blackman apodization function in all considered cases. The larger sensitivity 6.07 AU/RIU and 6.06 AU/RIU is obtained in Bessel apodization function and Barthann apodization function, respectively. Since, Bessel apodization function shows lower (0.1500 nm) fullwidth half maximum value in comparison to the Barthann apodization function, therefore it gives maximum detection accuracy10329 and quality parameter 40.47 AU/nm-RIU. Followed by Bessel apodization function the Gaussian apodization function also shows high detection accuracy10030 and quality parameter 38.18 AU/nm-RIU due to its lower (0.1545) fullwidth half maximum value. Here the considered Bessel apodization function is recommended for sensing applications.