Theoretical and experimental study of eigenstate locking in polarization self-modulated lasers

The temporal behavior of a polarization self-modulated laser is investigated theoretically and experimentally. The self-phase-locking of the eigenstates of such a laser is described theoretically by a set of coupled nonlinear differential equations governing the amplitudes and phases of the eigenstates. This permits us to reproduce the temporal signals obtained experimentally for different locations of the active medium with respect to the nodes and antinodes of the eigenstates. This proves unambiguously that such lasers are passively phase locked. This is confirmed experimentally and theoretically by the fact that the eigenstates can be unlocked by slightly altering the eigenstate spectrum, thus leading to a loss of the specific temporal behavior of such a polarization self-modulated laser.