Study on strain-induced polarization mode of strained-layer quantum-well 630-nm AlGaInP LD´s

Low-threshold operation of 630-nm AlGaInP LD´s is examined by introducing compressive and tensile strains into quantum wells (QW´s), and the dependence of threshold currents on the effects of strain is investigated. We also try to determine the correlation between the strain-induced polarization mode and threshold currents so as to optimize the strained QW structure for low threshold operation. Experimental results reveal a good correlation when the same device parameters are used. Based on that correlation, applying the larger strain and the QW-structure design that enhances the main polarization mode is effective in obtaining a low threshold. Opposite dependences of the relative intensity of the polarization mode on such device parameters as cavity length and facet reflectivity are observed under the two types of strain. Under tensile strain, the polarization-mode intensity increases as the mirror loss increases and the device temperature rises.<>