摘要
A frequently addressed problem in the study of spatial solitons is the dynamics of the beam at the interfaces between linear-nonlinear or nonlinear-nonlinear media [1]. In the higly nonlocal case, it has been shown that spatial solitons are robust enough to survive the transition and can either pass the interface without any changes or be totally internally reflected [2]. The trajectory can also be controlled by the power of the soliton [3]. Such features enable us in using solitons for all-optical computation. We study the dynamics of solitons launched in a medium with a modulated linear refractive index. Such modulations can give rise to interesting behavior in the propagation properties of the solitons. We observe that the optical soliton undergoes a transition from a wave-like to a particle-like behavior depending on the ratio between its width and the width of the defect, i.e. upon the power of the soliton. We solve the one-dimensional Nonlinear Schrdinger Equation of the form equation for an input soliton u(X,Z = 0) = u0sech(u0X), where Veff (X,Z) = [n2L(X,Z) + 2n 0nL(X,Z)], nL(X,Z) is the linear index profile, k0 = 2/ is the vacuum wave vector ( is the vacuum wavelength), p = k20w2p/2, wp is the width of the defect, equation is the normalized field, A is the electric field, n2 is the Kerr coefficient and n0 is the linear refractive index for the carrier; we also define the normalized coordinates Z = z/L d (Ld = k0w2pn 0) and X = x/wp. The defect has a super-Gaussian profile in X and lies between Z = 2 and Z = 2.5. © 2011 IEEE.