Robustness of Quadratic Solitons with Periodic Gain
  We address the robustness of quadratic solitons with periodic non-conservative perturbations. We find the evolution equations for guiding-center solitons under conditions for second-harmonic generation in the presence of periodic multi-band loss and gain. Under proper conditions, a robust guiding-center soliton formation is revealed. 
Lluis Torner, Juan P. Torres, and Ole Bang