A high-performance 5-junction cascade quantum dot (QD) vertical cavity surface-emitting laser (VCSEL) with 1.3â µm wavelength was designed. The characteristics of the QD as active regions and tunnel junctions are combined to effectively increase output power. The photoelectric characteristics of single-junction, 3-junction cascade, and 5-junction cascade QD VCSELs are compared at continuous-wave conditions. Results indicate that the threshold current gradually decreases, and the output power and slope efficiency exponential increase with the increase of the number of active regions. The peak power conversion efficiency of 58.4% is achieved for the 5-junction cascade individual QD VCSEL emitter with 10â µm oxide aperture. The maximum slope efficiency of the device is 6.27â W/A, which is approximately six times than that of the single-junction QD VCSEL. The output power of the 5-junction cascade QD VCSEL reaches 188.13â mW at injection current 30â mA. High-performance multi-junction cascade 1.3-µm QD VCSEL provides data and theoretical support for the preparation of epitaxial materials.
A GaInAsP/GaAs/GaAsP Al-free laser with asymmetric potential barriers is designed theoretically to prevent carrier leakage. The band alignment demonstrates that a high height of the potential barrier decreases the leakage current. The internal quantum efficiency increases by increasing the injection efficiency, which is attributed to the decreasing electron potential barrier heights. Moreover, the threshold current and operating voltage decrease by adopting a novel barrier so that the output power and power conversion efficiency (PCE) increase. When the injection current is 5â kA/cm2, the PCE is 77.82% and the output power is 13.21 W. The physical mechanism of potential barrier heights affecting carrier transport is investigated, which will provide a theoretical basis for optimizing laser diodes.
