Sa. Darmanyan et M. Neviere, Dichromatic nonlinear eigenmodes in slab waveguide with chi((2)) nonlinearity - art. no. 036613, PHYS REV E, 6303(3), 2001, pp. 6613
The existence of purely nonlinear eigenmodes in a waveguiding structure com
posed of a slab with quadratic nonlinearity surrounded by (non)linear cladd
ings is reported. Modes having bright and dark solitonlike shapes and consi
sting of two mutually locked harmonics are identified. Asymmetrical modes a
re shown to exist in symmetrical environments. Constraints for the existenc
e of the modes are derived in terms of parameters of guiding structure mate
rials.