PERTURBATIVE APPROACH TO THE INTERACTION OF SOLITONS IN QUADRATIC NONLINEAR MEDIA

We investigate the interaction between one-dimensional bright solitary waves in quadratic nonlinear media. We use a perturbational approach via collective coordinates to reduce the full evolution equations to a set of coupled ordinary differential equations which provides a simpl e qualitative picture of the soliton interactions. We use the scheme t o calculate the collision distance between equal amplitude solitons an d compare the results with the outcome of direct numerical solution of the evolution equations. A good agreement is found.