DEPENDENCE OF POLARIZATION MODE AND THRESHOLD CURRENT ON TENSILE STRAIN IN ALGAAS GAASP QUANTUM-WELL LASERS/

Trends in threshold current and other device characteristics were meas ured in a series of tensile-strained Al0.34Ga0.66As/GaAs1-yPy separate confinement heterostructure single quantum-well (SCH-SQW) lasers. Ten sile strain in the wells was varied between 0 and 1% by changing the p hosphorous composition from 0 to 30%. For short (300 mu m) cavity leng th, devices with 15% P demonstrated the lowest threshold current densi ty of 330 A/cm(2). For longer cavities, the threshold was lowest (195 A/cm(2)) for nearly lattice-matched devices, and increased slightly wi th higher P compositions up to 18% (222 A/cm(2)). The output of the te nsile-strained lasers is transverse magnetic (TM) polarized for device s with 29% P in the well. (C) 1997 Elsevier Science Ltd.