  Optical and electrical characteristics of AlGaAs lasers with separate
confinement heterostructures are modeled by using Synopsys's Sentaurus TCAD,
and open source software. The results for cases of 2-QW (2 Quantum Wells) and
3-QW structures are compared with these for 1-QW. A significant improvement of
useful laser parameters is obtained by increasing the number of Quantum Wells
and optimizing the width of waveguides. In particular, the maximum optical
efficiency is shown to reach 88% for a 3-QW structure with optimal width of
waveguides. The width of optical intensity profile of MQW lasers increases,
leading to lowering maximal light power density passing through laser facets,
decreasing the risk of catastrophic damage of mirrors.
