S. G. Dinev, A. A. Dreischuh, D. Lavaldjiev, K. D. Krastev
We find conditions for collimation and guiding of two light beams in a nonlinear bulk medium. The spatial parameters of each beam of the symbiotically coupled pair depend critically on the cross-phase modulation from the complementary beam. The diffraction divergence and self-phase modulation can be offset by proper choice of the wavelength, the value and the sign of the nonlinear susceptibility of the medium.