Analysis of dispersion properties of microstructured fibers with Kerr nonlinearity and with saturable gain by nonlinear eigenmode expansion

In the present paper a microstructured optical fiber composed from a solid core surrounded by a photonic crystal cladding region is considered. The analysis of nonlinear eigenmodes of the microstructured fiber is presented. The calculation of the nonlinear eigenmodes allows in the first order to define effect of strong self-focusing and saturable gain to dispersion and gain properties of the fibre. For the expansion of the modal profiles on the set of Laguerre-Gaussian functions was used. The properties of azimuthal symmetry of the photonic crystal cladding allow to reduce the number of governed functions in comparison with the method based on the field approximation by Hermite-Gaussian functions.