Soliton-like propagation in dispersion-managed silicon nanowaveguides

Over the last few years, significant research effort has been devoted to the study of nonlinear phenomena in silicon nanowaveguides (SNWs) [1]. In particular, the capability for extensively engineering the dispersion characteristics of SNWs [1], has directed considerable interest to the dynamics of femtosecond solitonic pulses [2]. However, the formation of pure solitons in SNWs is hindered (besides linear propagation losses) by the presence of nonlinear losses, namely, two-photon (TPA) and free-carrier absorption (FCA). Despite these extra loss mechanisms, we demonstrate in this work the possibility for quasi-soliton propagation in dispersion-managed SNWs. Both single-pulse and, more importantly, pulse-train cases are thoroughly examined, by employing a vectorial nonlinear Schrödinger equation (NLSE) formulation [4], rigorously taking into account all relevant phenomena, including free-carrier and higher-order nonlinear effects such as self-steepening.