Theoretical analysis of band structures and lasing characteristics in strained quantum wire lasers

The lasing characteristics of strained quantum wire lasers are analyzed using a tight binding calculation, and improved dynamic and spectral properties are predicted. An InGaAs quantum wire embedded in a plane of InAlGaAs with the same lattice constant and sandwiched by two-dimensional barrier layers of AlGaAs is considered. In this structure the biaxial strain effect appears together with the two-dimensional confinement effect. The results of the tight binding calculation indicate that the band mixing effect, which inherently exists in the valence bands of GaAs-AlGaAs quantum wires, is suppressed. In addition, the difference between the effective masses of the first conduction band and the first valence band is reduced as compared to the GaAlAs bulk and to GaAs-AlGaAs quantum wells and wires. Thus the advantages of both the quantum wire effect and the strain effect are incorporated in this structure. Calculation of the modulation dynamics and the spectral properties of the strained quantum wire lasers show significant enhancements