Thermal Analysis Of Mid-infrared Semiconductor Lasers

Ⅲ-Ⅴ compound semiconductor lasers have many applications in UV, visible and infrared bands. However, the performances of the lasers, including threshold current, spectral characteristics and operating conditions, are greatly influenced by the thermal property. From this point of view, in this Ph.D dissertation, the thermal behaviors of 2μm band antimonide MQW lasers and mid-infrared quantum cascade lasers are studied by using numerical approach. The main contents are as follows:1. Based on former works, the finite element method (FEM) is introduced for the thermal analysis of those semiconductor lasers. The simulation processes, including modeling and meshing procedure, is optimized thoroughly. The effectiveness and precision of the analysis are improved dramatically by considering the parameters of real device and material properties.2. The thermal conductivities of ternary and quaternary materials, which are still in lack of experimental data, are evaluated by using Abeles' approach and interpolation method. In order to calculate the thermal conductivity of the active region of quantum cascade lasers, thermal boundary resistance (TBR) is introduced for the first time, and diffuse mismatch method (DMM) is used for calculating TBR. Furthermore, the specific heats of different Ⅲ-Ⅴ materials are calculated by using Debye's law.3. The thermal behavior and various chip packaging methods of mid-infrared semiconductor lasers are studied based on real devices. The analyzed lasers include AlGaAsSb/InGaAsSb ridge waveguide multi-quantum well laser, InAsP/InGaAsP ridge waveguide MQW laser, InGaAs/InAlAs and InGaAs/AlGaAsSb quantum cascade lasers and so on. The thermal performances of different chip packaging methods are studied under continuous wave operation. Whereas for pulse operation, we introduce thermal time constants to characterize the cooling performance. More over, the influences of different structural parameters, material systems and heatsink temperatures are calculated and compared with exiting experimental data. Finally, the...