We present an experimental study of the dynamics of a high power Yb3+-doped double-clad fiber laser in various optical configurations operating in the 1.08 mum wavelength. The fiber is side-pumped with a high power laser diode using the V-groove technique. Different self-pulsing regimes are identified resulting from third-order nonlinear effects. The influence of the cavity losses on the dynamical behavior is also investigated. In addition, we show that the system is efficiently stabilized in a unidirectional ring cavity where Brillouin backscattering is suppressed. (C) 2000 Published by Elsevier Science B.V.