Fiber Bragg grating employing novel apodization profile: performance optimization for quasi-distributed sensing applications

The focus of this paper is to achieve greater efficiency of fiber Bragg grating (FBG) based all-optical quasi-distributed sensing network by suitably tailoring and controlling the key optical characteristics of the FBG. Apodization profile plays a critical role in order to achieve optimum optical characteristics for the FBG. FBG with a novel apodization profile and optimized optical characteristics with respect to the key grating parameters is reported for this purpose. Performance characteristics that are critically important for optical communication as well as sensor applications are rigorously and comparatively analyzed for the FBG employing proposed apodization profile and other selected elite apodization profiles. Simulation results show that among all the apodization profiles included in the theoretical analysis, best side-lobe suppression characteristics along with a FWHM of 0.14 nm (< 0.2 nm) and reflectivity of 0.607 (> 0.5) are observed for the proposed apodization profile at optimum grating parameters (L = 10 mm and delta n = 0.9 x 10(-4)). The proposed FBG with optimized characteristics is then employed in a five-stage quasi-distributed temperature and strain sensing network to analyze its application efficiency. An isolation of 11.15 dB and the total isolation of 33.508 dB, highest among the other apodization profiles studied in this research, are observed for the proposed grating. Further, a large dynamic range for the temperature/strain measurement up to 131.6 degrees C/1450 mu epsilon is achieved.