Spectral and Dispersion Properties of Long Period Fiber Grating for Optical Communication Systems

Present work deals with the analytical study of spectral and dispersion properties of long period fiber grating (LPFG) under linear regime. The standard parameters in the understanding of the optical features of an LPFG have been analyzed using the linear coupling processes such that one can appreciate without going through the cumbersome mathematical treatment of coupled mode equations the basic characteristics of the grating. We have analyze transmittance, phase factor, group delay and group velocity dispersion (GVD) of the LPFG as functions of physical parameters like operating wavelength, grating length, induced index change, and detuning parameter. Special attention is paid to the study of GVD with second and third order dispersion contribution as well as the filter characteristics and delay response of the grating. In case of strong grating, we find that at a particular grating strength the resonance band splits into two bands. Negative group delay for certain values of coupling strength suggested that an LPFG can also be used as dispersion compensator in optical fiber communication.