Study Of Chirps Induced By Nonlinear Effects In The Negative Refractive Medium

Negative refractive medium are the artificial complex medium with simultaneously negative electric and magnetic responses (ε<0,μ<0 ),when electromagnetic wave propagate in this medium, the wave vector k ,electric field E and magnetic field H satisfy left-hand law, so them present lots of novel optical properties, recent years, the research of negative refractive medium deepened increasingly.In this paper, Based on the generalized nonlinear schr(o|¨)dingerequation of negative refractive medium, the chirp evolution of dispersion and nonlinear effects in negative refractive medium are simulated by using the Split-step Fourier method, through the analysis of chirp, the role of the nonlinear effects in pulse propagation was analyzed, and provide theoretical basis for the research of nonlinear effects in negative refraction medium.Emphatically analyzed the chirp of self-steepening, second-order nonlinear dispersion and third-order nonlinear dispersion, discussed their effect in ultra-short pulse transmission. The results shown that, the positive and negative controllable characteristics of self-steepening coefficient makes the pulsed center shift to front edge and trailing edge. The second-order nonlinear dispersion does not change the symmetry of chirp, it generates a positive chirp when the coefficient is positive, and leads to the broadening of pulse in normal dispersion area, the compression of pulse in anomalous dispersion area. And it generates a negative chirp when the coefficient is negative, this leads to the compression of pulse in normal dispersion area,the broadening of pulse in anomalous dispersion area. The third-order nonlinear dispersion leads the pulse center shift to the front edge, within the range of 0 <ω/ω_pe < 0.6 ,the effect of third-order nonlinear dispersion can be neglected,while in the range ofo.6≤ω/ω_pr≤0.7 ,it effect should be considered.