Tensile strained InGaAs/AlGaInAs MQW laser emitting at 1.55 μm

Abstract

The optical gain of tensile strained MQW lasers emitting at 1.55 μm are compared for two quaternary materials In1-xGaxAs/In0.52 (Al1-zGaz)0.48As/InP and In1-xGaxAs/GaxIn1-xAs yP1-y/InP. The barrier material bandgap is kept at 1.0 eV. At an injection carrier density of 1.2×1018cm-3, and at a tensile strain of 0.3 to 0.6%, the latter system gives a slightly higher peak gain ranging from 5000 - 6500 cm-1. This is because it has a smaller quantum well width (2 nm smaller) resulting in higher density of states and thus an enhanced optical gain. However, the former has En1 of 135 meV below the barrier compared to 64.7 meV of the latter, which implies a better control of carrier leakage at higher temperature operation, which is a desirable characteristic. Finally, the statistical fluctuation of structural parameters, which is assumed to obey normal distribution, of In1-xGaxAs/In0.52 (Al1-zGaz)0.48As/InP laser is studied. The optical gain is extremely sensitive to changes in Gallium composition x of the well. A 2% deviation will shift the peak emission energy and the peak gain is deteriorated. Deviation in quantum well width and A1 composition hardly changes the overall optical gain.