Few-cycle soliton propagation

Soliton propagation is usually described in the “slowly varying envelope approximation” regime, which is not applicable for ultrashort pulses. We present theoretical results and numerical simulations for both nonlinear Schrödinger and parametric $\left({\chi }^{\mathrm{}\left(2\right)\mathrm{}}\right)$ ultrashort solitons in the “generalized few-cycle envelope approximation” regime, demonstrating their altered propagation.