Antiphase dynamics and polarization effects in the Nd-doped fiber laser

The response of an Nd-doped optical fiber laser to modulation of the pump power reveals that the polarization of the laser light plays an important role in the linear and nonlinear dynamics of this laser. Experiments have been carried out under pulsed or sinusoidal modulation of the pump power as well as in the continuous-wave regime. Most of the observed phenomena may be interpreted in the framework of a theory of the two-mode laser in which each mode is associated with one polarization eigenstate of the laser. Effects such as the appearance of slow modes and antiphase behavior have also been observed. A model of a two-mode laser including spontaneous emission is theoretically and numerically analyzed. It reproduces well most of the experimental findings.