ERBIUM LASER MODEL FOR 2-WAVELENGTH OPERATION

A theoretical modeling of dual wavelength operation of erbium-doped fi bre lasers is presented. The model is a generalization of the one used in the single mode theory, based on the existence of isolated ions an d ion pairs coupled via the laser field. Analytical results are obtain ed in the steady state. The linear stability analysis of the coupled e quations shows the existence of two pairs of complex conjugate eigenva lues and two real negative eigenvalues. These results imply that the s ystem is driving by two frequencies: one associated with the classical relaxation oscillation and a low frequency characteristic of a bimoda l system. When the ion pair concentration is increased, the real part of one pair of conjugate eigenvalues becomes positive. In such a situa tion, self-pulsing and chaotic dynamics occur together with antiphase effects between two mode intensities. Locking of the low frequency on a subharmonic of the high frequency is alos obtained leading to nT-per iodic orbits.