Characterization of LPGs via correlation analysis of an analytical solution with observed transmission spectra

In this paper, we describe a technique to characterize long period fiber gratings (LPG) by use of a correlation between the measured transmission spectrum and a theoretical model. The model is robust enough to require only a-priori knowledge of the fiber design and the inscription period. We demonstrate the application of this technique on an example LPG resulting in the calculation of the dispersive core index, length, and strength of the grating to better than experimental error. The technique is further expanded to allow for the modeling of metal jacketed long period gratings by use of an extended version of Erdogan's model