Quantum well width and In composition effects on the operating characteristics of InGaAs/GaAs strained single quantum well diode lasers

In this work we study the effect of strain on the performance of highly strained InxGa1−xAs/GaAs/GaAlAs quantum well lasers (SQWL). We changed the indium concentration and the QW width and found that the threshold current density, Jth, is minimal with x∼0.4 when the width of the QW is 20 Å. For x=0.3 the minimal Jth was obtained with a 90 Å active layer. The best performing laser reported in this work has Jth=68 A/cm2 emitting at 1.063 μm with cavity length of 2022 μm. Comparison with GaAs/GaAlAs lasers is possible because both structures have the same optical mode confinement, and the comparison shows that SQWLs have indeed lower Jth, but the improvement in Jth with the strain is not as dramatic as predicted theoretically.