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Filamentation commonly occurs in broad area semiconductor
laser due to two intinsic mechanisms: carrier-induced index
change and intensity-induced index change. In this thesis, we
investigate the effects of thesetwo mechanisms to the formation
of filaments in semiconductor lasers theoretically. The
theoretical model is derived thoroughly and two numericalmethods
are used to calculate it, and they are 2-D Beam Propagation
Method and 1-D Nonlinear Eigen-Equation method. The results show
that when the magnitude of the carrier density and electric
field intensity existing inside the laser cavity are higher,
smaller stripe width is needed for the lasers to avoid occurring
filamentation. Furthermore, unsymmetry laserstructure will be
lower down the critical stripe width of the lasers. Finally, our
results suggest the possibility of obtaining large stripe width
semiconductor laser diodes (50um) without filamentation by using
compensation between these two mechanisms.
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