In this paper the generation of stable ns pulses by a laser diode pumped Yb-doped double-clad fiber laser is demonstrated. The fiber laser with two-mirror cavity operates in a self-Q-switching regime, the Q-switch mechanism of which is based on stimulated Brillouin scattering (SBS). With different reflectivity of the second mirror, stable, pulse width ranging of 10 ns to less than 2 ns pulses are obtained. (c) 2006 Wiley Periodicals, Inc.