Numerical analysis of GVD and TOD compensation at 160 Gb/s long-haul transmission using fiber bragg grating

Abstract

Group velocity dispersion (GVD) and third-order dispersion (TOD) have severe deleterious impact on the system performance at ultrahigh speed optical communication. GVD results in broadening of the propagating pulse causing inter-symbol interference between adjacent pulses whereas TOD contributes to the unwanted oscillation in the leading and trailing edges of the pulse in addition to broadening. In this thesis, a ber Bragg grating (FBG) based optical ber transmission model that can compensate for both GVD and TOD is modeled and investigated. Modeling of FBG is performed by nonlinear coupled-mode equations which is solved by transfer matrix method. An optimization of in-line dispersion compensation using FBG is also presented. Dispersion compensating ber (DCF) based optical transmission models are also numerically investigated and performances are evaluated for comparison. Optical ber transmission model is simulated by nonlinear Schr odinger equation. The e ect of GVD and TOD compensation is studied extensively at 160 Gb/s. Two optical simulation tools have been used in this simulation: the OPTIGRATING and the OPTISYSTEM. OPTIGRATING is a device simulator software used to design the FBG for various purposes whereas OPTISYSTEM is an optical communication system simulator used to measure the performance of the system. FBG is employed in the transmission line in places where DCF was conventionally used and the system performance is evaluated for both FBG and DCF based model using OPTISYSTEM software. In addition to that MATLAB is used to visualize and interpret the results. FBG based systems are found to be more promising solution of overall dispersion compensation at ultrahigh speed. Further demonstration of optimization has showed that dispersion compensation with bi-end con guration using FBG and NZDSF ber gives even better performance. This analysis might be helpful to design next-generation high speed and ultrahigh speed optical ber communication system with better compensation and superior system performance.