Minimization of the linewidth enhancement factor in compressively strained semiconductor lasers

A comprehensive model for the optical response of a semiconductor quantum well, including valence subband mixing and many-body effects, is used to theoretically investigate means of minimizing the linewidth enhancement factor. The effects of well width and compressive strain are analyzed, and the contribution of many-body effects evaluated. Compressive strain in narrow quantum wells generally leads to reduction of the linewidth enhancement factor at gain peak. In addition, many-body effects, particularly bandgap renormalization, admit the possibility that by small detuning to below the gain peak position, a zero value is possible.