EXACT N-SOLITON SOLUTIONS OF THE EXTENDED NONLINEAR SCHRODINGER-EQUATION

By use of Hirota's direct method and a simple transformation, we obtain the exact N-soliton solutions of the extended nonlinear Schrodinger equation, i partial derivative q/partial derivative z - k''/2 partial derivative 2q/partial derivative t2 + beta Absolute value of q 2q + igamma partial derivative(Absolute value of q 2q)/partial derivative t - i k'''/6 partial derivative 3q/partial derivative t3 = 0, under the conditions 3k''gamma = betak''' and k''gamma = betak''', respectively. The features of the solutions are discussed.