Dispersion compensation based on optical grating for long haul and high speed fiberoptical telecommunication systems

viDISPERSION COMPENSATION BASED ON OPTICAL GRATINGFOR LONG HAUL AND HIGH SPEED FIBEROPTICALTELECOMMUNICATION SYSTEMS(PhD Thesis)sa NAVRUZGAZ UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYDecember 2006ABSTRACTThe wonderful improvements in communication technologies and the increasingdata rate have forced the fiber optical networks and communication channelcapacities day by day all over the world. Dispersion is the most important factorthat limits the data transmission distance in the fiber optical communicationsystems that passed to a new age by the application of optical amplifiers. It isnecessary to control the dispersion which reduces dramatically the transmissionrate and causes the optical pulse to entire in an undesired way.Nowadays, there is an intense interest to fiber Bragg gratings which can be anoptical component of fiber optical communication systems while cope withdispersion. In this study, researches are carried out in order to improve thefiber Bragg gratings as a well optical filter and an optical compensator at thesame time. First of all, in order to analyze the optical grating numerically, amodel solving the ?coupled mode equation system? by ?matrix transfermethod? is exposed. For the application of this model that involves theparameters, that effects the optical characteristics of fiber Bragg grating, designwavelength, refraction index modulation amplitude, operating wavelengthbandwidth, apodization, grating length, linear and nonlinear chirp, a simulatoris improved working under MATLAB software. By this simulator, theviioptimization analysis of power reflectivity, group time delay and dispersionspectra are realized and design examples that can be applied in practical arepresented.As a next step the design model and the simulator software is improved and theoptical fiber communication systems are examined on the fiber grating complexstructures and their effects. Different amplitude and phase sampling functionsare analyzed and the optical grating spectral characteristics that use thesefunctions are tested. Finally, an optimization has been realized by phasesampling approximation and a super structure FBG design has been presented.The calculated spectral characteristics and results have shown that phasesampled FBG is very successful.Science Code : 704.1.111Key Words : Fiber Bragg grating, dispersion compensationPage Number : 120Adviser : Prof. Dr. Fatma Nihal GÜLER