Differential gain and threshold current of 1.3 μm tensile-strained InGaAsP multi quantum well buried-heterostructure lasers grown by metalorganic molecular beam epitaxial growth

The laser characteristics of 1.3 μm tensile-strained InGaAsP/InP multi quantum well (MQW) lasers were studied. The tensile strain of well layers ranged from 0.5% to 1.8%. The level of the strain dependence of the threshold current shows that the threshold current decreases drastically with increase in the tensile strain from 0.5% to 1.3%, while it stays almost constant in the 1.45%-1.8% range. Among all the samples, the 1.3% tensile-strained MQW laser shows superior performance in terms of minimum threshold current and maximum differential gain (∂g/∂N). The 1.3% tensile strain is the optimum level for the tensile-strained MQW buried-heterostructure lasers.