  Computer simulations with Synopsys' Sentaurus TCAD are used to study the
effect of the molar concentration of aluminum in the active and waveguide
regions on the energy spectrum of carriers in Quantum Well (QW) and the optical
spectral characteristics of radiation of semiconductor lasers with AlxGa1-xAs
double heterostructures and separate confinement (SCH). Wavelength of
single-mode lasers is shown to be almost independent of the concentration of
aluminum in the waveguide, in a wide range of aluminum content, but to depend
mainly on Al concentrations in QW region.
