In this paper, the experimental results of self-injection phase locking in a 10 W, single element wide broad-area diode laser are presented. The width of the emitting area of this diode is 1000 μm, to our knowledge it is the broadest single element diode laser that until now has been used in an external feedback cavity. The beam quality of the diode laser is improved by the asymmetric self-injection phase locking technique. The far-field and near-field profiles are measured with and without the self-injection phase locking at different operating currents. 3.65 W output power is obtained with the operating current of 13.0 A, with a beam quality factor M 2 of 16.6, which is improved with a factor of 14 by the self-injection phase locking technique.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.