Considering linear and nonlinear optical effects like group velocity dispersion, higher-order dispersion, Kerr nonlinearity, self-steepening, stimulated Raman scattering we obtain a higherorder nonlinear Schrödinger equation describing the propagation of ultra-short pulse in optical fiber. We construct exact bright and dark solitary wave solutions of the generalized obtained equation, obeying to some constraint relations between coefficient's equation via the Bogning-Djeumen Tchaho-Kofané method (BDKm). The generalized higher-order nonlinear Schrödinger equation is obtained by affecting coefficients n i (i=0, 1, .., 5) to different terms of non modified equation. New solutions are obtained, and the term or higher-order dispersion can be considered as the new selector of solitary wave-type propagating in the higher-order nonlinear optical fiber.
IntroductionDuring the last few decades, nonlinear partial differential equations (NPDEs) have seriously draw the attention of the world scientific research. These NPDEs permit to model phenomena in several fields of sciences, notably in physics, such as fluid mechanics, electronics, plasma physics, condensate mater and optical fiber communication [1][2][3][4][5][6][7].The numerical or analytical studies of NPDEs are one of the very important and essential tasks in nonlinear sciences, but the construction of exact solutions plays a very important role, because they can provide much information for a best comprehension of a physical problem. That is why some mathematical methods have been developed to solve NPDEs. We can quote the tanh method, the extended tanh method, the Jacobi's elliptic function algorithm, the Riccati's equation and G′/G method [8][9][10][11][12][13]. The use of these different methods leads to the achievement of travelling wave solutions, periodic solutions and solitary wave solutions. Solitary waves are particular type of solutions of NPDEs with special property. They propagate without changing their shape.The importance of soliton theory in nonlinear science is no more to prove. In area of optical fiber, soliton can be observed, due to the equilibrium between the dispersion and nonlinear effects in the media [14,15]. In communication sciences, solitary wave solutions act as information carrier bits through optical fibers [16,17]. The long distance wired communication across transoceanic and transcontinental distances is now done using optical solitons, and the quantity of information and their transmission speed are unbeatable [18].The propagation of the light in a media is suspected to the dispersion effects and nonlinear effects, which can be of higher-order or not [19,20]. For nonlinear effects, we can note here: Kerr effect or self phase modulation, stimulated brillouin scattering, self-steepening and stimulated Raman scattering [20,21].