The Study Of Bright Soliton Solutions For The Coupled Nonlinear Schr?dinger Equation In Inhomogeneous Fibers

With the development of fiber soliton theory and the practicality of optical soliton communication system,the research of optical fiber nonlinear optics has attracted much attention.In nonlinear optics,the basic theoretical model of optical pulse propagation is usually described by coupled nonlinear Schrodinger equation.In this paper,two coupled nonlinear Schrodinger equations with variable coefficients are studied by Hirota bilinear method in the background of optical fiber communication.1.The propagation of ultra-short pulses in an inhomogeneous fibers is described by coupled higher-order nonlinear Schrodinger equation with variable coefficients.Firstly,in this paper,the bright one-soliton solutions and two-soliton solutions are obtained by the Hirota bilinear method.Secondly,intensity functions are obtained by assigning the characteristic parameters of solutions,and the corresponding intensity images of soliton are drawn by Maple software.Finally,the propagation characteristics of the beam and the effects of the group-velocity dispersion,third-order dispersion and dispersion gain on soliton transmission,especially on the waveform of one-soliton pulse and two soliton pulse,are analyzed.2.(2+1)-dimensional variable coefficients coupled nonlinear Schrodinger equation describes the propagation of a continuous-wave beam inside a graded-index nonlinear waveguide amplifier with an additional long-period grating.Firstly,in this paper,bright one-soliton and two-soliton solutions are obtained by Hirota bilinear method.Secondly,intensity images of soliton are drawed by Maple software.Propagation characteristics of the beam,diffraction effect,nonlinear effect and fiber loss on soliton transmission are visually analyzed by the image.Finally,the evolution images of Kuznetsov-Ma solitons solution are obtained and the propagation characteristics of Kuznetsov-Ma solitons are analyzed.