Deformation of modulated wave groups in third-order nonlinear media

We present a numerical and analytical investigation of the deformation of a modulated wave group in third-order nonlinear media. Numerical results sho w that an optical pulse that is initially bichromatic can deform substantia lly with large variations in amplitude and phase. For specific cases, the b i-chromatic pulse deforms into a train of temporal solitons. Based on the c oupled phase-amplitude equation of Nonlinear Schrodinger (NLS), the initial deformation of the modulated wave-packet will be explained and an instabil ity condition can be derived. Energy arguments are given that provide an al ternative derivation of the instability condition.