Low-frequency dynamics of a class B laser with two elliptically polarised modes

The dynamics of a neodymium-doped bipolarised fibre laser were investigated both theoretically and experimentally. It was found that the state of pump polarisation affects the intensity ratio of polarisation modes. The intensity fluctuation spectrum of each polarisation mode exhibits three relaxation peaks. The observed experimental features of low-frequency dynamics of the fibre laser are explained on the basis of an advanced model of a class B laser with two orthogonal elliptically polarised modes.