Abstract
Broad-area semiconductor lasers and amplifiers suffer from the well-known "filamentation" problem manifested through the break up of the lateral mode into multiple filaments.1,2 As the local intensity increases, the gain saturates (spatial hole burning), thereby increasing the local refractive index, resulting in a self-focusing effect. For wide current stripes, this carrier-induced self-focusing can be catastrophic, leading to filamentation. This effect is combatted by diffraction, which spreads out the "hot spots" in the lateral field, and by gain saturation, which reduces the local gain, thereby allowing the surrounding regions to increase in intensity. For certain conditions, these factors can remove filamentation for small enough values of α (α < 0.5).3 However, because GaAs-based lasers typically have a values in the range 2–5, they cannot operate stably for stripe widths in excess of 15 μm.
© 1996 Optical Society of America
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