Investigation of self-organized degenerate second-order nonlinear optical interactions in optical fibers around and above the saturation

New experiments on self-organized degenerate second-order nonlinear optical interactions in optical fibers were performed. The Anderson saturation formula was experimentally verified and a self-organized degenerate parametric down conversion was demonstrated. A photo-induced permanent reflectivity of optical fibers was discovered when launching a strong second-harmonic green light together along a relatively weak fundamental IR radiation into the fiber for about 10 minutes.