The criterion of modulational instability the second order bright solitary wave is studied in this article. Principle consists initially seeking all solutions type which verify nonlinear partial differential equation governs dynamics propagation flattened optical fibers. When reference solution to be subjected a disturbance identified, next step establishing condition stability/instability.

We describe observations of various transverse instabilities that occur when two laser beams intersect in nonlinear optical liquids. Patterns that we observe include two types of conical emission and the generation of a linear array of spots. These results can be understood in terms of the physical processes of self-diffraction, two-beam-excited conical emission, and seeded modulational instabi...