Dependence of linewidth enhancement factor α on waveguide structure in semiconductor lasers

Abstract

In semiconductor lasers, the ratio α of the real part to the imaginary part of the change in refractive index due to the change in carrier density determines the magnitude of dynamic and static line broadenings. The letter reports that the effective value of α depends on the structure of the waveguide, where both index and gain mechanisms induce transverse-mode guiding.