Stable Control of Pulse Speed in Parametric Three-Wave Solitons
  We analyze the control of the propagation speed of three wave packets interacting in a medium with quadratic nonlinearity and dispersion. We found analytical expressions for mutually trapped pulses with a common velocity in the form of a three-parameter family of solutions of the three-wave resonant interaction. The stability of these novel parametric solitons is simply related to the value of their common group velocity. 
Antonio Degasperis, Matteo Conforti, Fabio Baronio, Stefan Wabnitz