Self-consistent analysis of GaInNAsSb/GaSb quantum well lasers emitting at 2.3-3.3-μm-long wavelength

Double-quantum-well GaInNAsSb laser structures grown on GaSb substrate emitting between 2.3 and 3.3 μm are proposed, and modeled self-consistently using a commercial software that combines gain calculation with 2-D simulations of carrier transport and waveguiding. The model is calibrated using experimental results obtained from conventional GaInAsSb lasers emitting at 2.3 μm. The simulated results show that the incorporation of a small concentration of nitrogen in the conventional InGaAsSb can extend the wavelength to 3.3 μm with a reasonable threshold current density increase. This is obtained as a result of preserving good confinement for holes as compared to conventional InGaAsSb 2.3-μm laser. The threshold current density increase with wavelength is attributed mainly to nonuniform distribution of carriers due to the high-conduction band offset. This drawback of the structure can be overcome by incorporating AlGaInAsSb material as a barrier and waveguide instead of AlGaAsSb. The simulation shows that the bandgap of the AlGaInAsSb quinternary material should be reduced linearly when increasing the wavelength to maintain a good laser performance in terms of emitted optical power.