Filamentation in high-power tapered semiconductor amplifiers

Filament formation is currently a limiting factor in the development of high power, spatially coherent semiconductor amplifiers. An experimental and theoretical investigation has been conducted to examine the filamentation tendencies of tapered amplifier structures. Experimental measurements of the far-field intensity distribution of a tapered amplifier which has been intentionally ''seeded'' to filament are compared to a perturbative solution of the paraxial wave equation. This model is used to address several design issues which can be optimized to suppress filamentation. The effect of non-uniform carrier injection due to carrier-induced bandgap changes is also investigated numerically.