טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentRosenthal Amir
SubjectInverse-Scattering Theory in Fiber Bragg Gratings
DepartmentDepartment of Electrical Engineering
Supervisor Professor Moshe Horowitz


Abstract

Inverse-scattering theory is used to reconstruct the profile of fiber gratings from their reflection and/or transmission spectrum. In this research, we have developed novel inverse-scattering methods, which enable us to reconstruct the structure of an almost arbitrary fiber Bragg grating. Our methods allow us to reduce the effect of noisy data on the reconstruction and to find the spatial loss along the grating. We have also found a bound on the spectral sampling resolution required to characterize fiber Bragg gratings. We have developed a novel theoretical method that enables us to extract the structure of long-period grating; we experimentally demonstrated this method for reconstructing, for the first time, the structure of a long-period grating.


In addition to the inverse-scattering problem in linear gratings, nonlinear effects in fiber Bragg gratings were also studied. We have used effects such as the reduced group velocity in gratings and soliton interaction to develop an efficient Bragg-soliton excitation scheme and to obtain theoretically very high pulse compression. We have also developed a method that enables, for the first time, to design nonlinear gratings with a moderate reflection.