Strain dependence of the linewidth enhancement factor in long-wavelength tensile- and compressive-strained quantum-well lasers

Values of the linewidth enhancement factor alpha in InGaAs/InGaAsP tensile- and compressive-strained quantum-well (QW) Fabry-Perot lasers are measured and compared to calculated values. The strain dependence of the measured values agrees with that of the calculated values: Values of alpha are smaller for tensile-strained QW lasers than for compressive-strained QW lasers, and alpha decreases with the increase of tensile or compressive strain. According to the model used in the calculation, short-wavelength-composition barriers reduce alpha in compressive-strained QW lasers, and alpha for such lasers is expected to be as low as that for the tensile-strained QW lasers.<>