Amplification of quadratic solitons in planar waveguides

We investigate soliton propagation in quadratic nonlinear media under the action of linear gain at the fundamental frequency band. The goal is to expose the potential of the process. In this regard, a reduced model of the gain mechanism applied to spatial solitons in planar waveguide settings is considered. Because quadratic solitons are multiple-frequency entities and only the fundamental wave directly experiences gain, the energy has to be continuously transferred to the second-harmonic from the amplified fundamental. Our numerical results are given