The effects of apodization profile on uniform fiber Bragg gratings

Abstract

The sensing applications of fiber Bragg gratings (FBGs) offer a high sensitivity, as well as other important advantages, such as real-time processing, long-term stability, immunity to electromagnetic interference, and convenient multiplexing capabilities. The reflection spectrum of fiber Bragg gratings with a uniform modulation of the refractive index is accompanied by series of sidelobes at the adjacent wavelength. It is very important to minimize and, if possible, eliminate the reflectivity of these sidelobes. The design of fiber Bragg gratings used Coupled Mode Theory. The coupled mode equations were solved by the Transfer Matrix Method since it was considered as good approximation to calculate the spectral response of fiber Bragg gratings. Apodization techniques are used to get optimized reflection spectrum. The uniform FBGs with several types of apodization were modeled in this project It was proven that apodization profile could be reduced the sidelobes. In addition, each profile also has the bandwidth and the maximum reflectivity better than others.