Tham khảo luận văn - đề án 'research report: "the propagation of ultrashort pulses keer environment."', luận văn - báo cáo phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ĐẠI HỌC VINH TẠP CHÍ KHQA HỌC TẬP XXXVI số 3A-2007 PROPAGATION EQUATION FOR ULTRASHORT PULSES IN KERR MEDIUM DINH XUAN KHQA a NGUYEN VIET HUNG b Abstract. In this article we investigated propagation of ultrashort lase pulses in the dispersive nonlinear medium. We showed the general propagation equation of pulses which includes the linear and nonlinear effects to all orders. In the specific case of Kerr medium we obtained the ultrashort pulse propagation equation called Generalized Nonlinear Schrodinger Equation. The impact of the third order dispersion the higher-order nonlinear terms self-steepening and stimulated Raman scattering were explicitly analyzed. I. INTRODUCTION Theoretical and experimental research for propagation process of ultrashort laser pulses in fs in a medium have been the subject of the intensive research in the last few years 1 3 9 12 . Because of special properties of these pulses during their propagation in the medium several new effects have been observed in comparison with the propagation process of short pulses in ps namely the effects of dispersion and nonlinear effects of higher orders. Under influence of these effects we have complicated changes both in amplitude and spectrum of the pulse. It splits into constituents and its spectrum also evolves into several bands which are known as optical shock and self-frequency shift phenomena 1 3 5 . These effects should be studied in detail for the future concrete applications of ultrashort pulses especially in the domain of optical communication. We apply the general formalism used for the pulse propagation problem in for the one-dimensional case. This formalism is based on the approximate expansion of the nonlinear wave equation which treats the nonlinear processes involved in the problem as the perturbations. In Sec. II we will present the theoretical model and the basis of the method and derive from these considerations the general equation for the pulse propagation process in the nonlinear .
