Semiconductor optical amplifying media with reduced self-focusing

A semiconductor light amplifying medium has reduced self-focusing and optical filamentation for providing higher power coherent outputs in broad-area laser and amplifier devices. In one embodiment, a longitudinally inhomogeneous active region has alternating segments of first gain portions and second compensating portions. The compensating portions have a negative self-focusing parameter [ DIFFERENTIAL n/ DIFFERENTIAL P] and may be light absorbing (negative gain) regions with negative antiguiding factor alpha or light amplifying (positive gain) regions with positive antiguiding factor alpha . The alpha -parameter is defined as the ratio of refractive index change per change in gain, as a function of carrier density. In a second embodiment, the medium may have longitudinally varying peak filament period so that filaments beginning to form in one portion of the active region are subsequently dispersed in a succeeding portion, slowing filament growth. In addition to self-focusing compensation, media with a lower alpha -parameter are provided by increasing the barrier height in quantum well active regions, straining or p-doping the active region, or a combination of these methods.