Nonlinear pulse propagation inside coupled silicon nanowires

摘要

In this work we describe the nonlinear propagation of optical pulses through an array of silicon nanowires made with the silicon-on-insulator technology. A generalized analysis of the nonlinear coupled system is given where we have considered the vector nature of optical modes and the effects of two-photon absorption on various nonlinear processes. The general theoretical model includes not only the effects of free-carrier absorption and free-carrier dispersion but also linear and nonlinear losses, and it extends previous vector nonlinear models to the case where coupling of supermodes of a waveguide array occurs in silicon waveguides. Analytical solutions are provided for the coupled-mode equations in some cases in which the density of the free carrier is relatively low, and dispersive effects are relatively weak, assuming that the nonlinear effects do not affect the waveguide modes significantly. The impact of two-photon absorption and free-carriers effect on the properties of the nonlinear coupling effects is studied in detail together with the evolution of optical power inside an array of silicon nanowires.