SATURATION EFFECTS ON MODULATIONAL INSTABILITY IN NON-KERR-LIKE MONOMODE OPTICAL FIBERS

Saturation effects on modulational instability in saturable non-Kerr-l ike semiconductor doped glass fibers in a steady-state regime are inve stigated. Several saturation functions for the induced nonlinear refra ctive-index changes are tested in a generalized nonlinear Schroedinger equation. It is found that the critical modulation frequency and the pin spectrum are sensitive to the precise saturation function chosen w henever the pump light transversal mode can be considered as having a homogeneous distribution over the cross section of the fiber core. Whe never the spatial inhomogeneity is taken into account, different satur ation functions lead to a similar behavior of both modulation frequenc y and gain spectrum dependence upon incident power.