Diffraction managed vortex soliton in competing cubic-quintic nonlinear media

We study analytically and numerically vortex solitons in competing cubic-quintic nonlinear media with normal and anomalous fourth order diffraction (FOD). Bifurcated solutions of vortex solitons are obtained with variational (Lagrangian) approach. Propagation dynamics are demonstrated with split-step Fourier transform, which show that normal (anomalous) FOD can weaken (enhance) the stable propagation distance of vortex solitons. Furthermore, stability of vortex solitons is determined by Vakhitov-Kolokolov (VK) criteria. The upper branch of vortex solitons is unstable, whereas, the lower branch of vortex solitons is robust against perturbations.