Thermal properties of multiple layers including distributed Bragg reflector (DBR) and multiple quantum wells (MQWs) used in the semiconductor gain element are crucial for the performance of a semiconductor disk laser (SDL). For the purpose of more reasonable semiconductor wafer design, so to improve the thermal management of SDLs, accurate thermal conductivity value of a DBR is under considerable requirement. By the use of equilibrium molecular dynamics (EMD) method, thermal conductivities of AlAs/GaAs DBRs, which were widely employed in 1μm wavelength SDLs, were calculated, and simulated results were compared with reported data. Influences of the Al composition, and the layer thickness on the thermal conductivities were focused and analyzed.
Based on generalized heat transfer model of thermoelectric cooler(TEC), the heat management model of semiconductor disk laser with TEC cooler has been built. With finite element method, this article has calculated the temperature distribution characteristics, and studied the effects of TEC current, heat exchange coefficient, the heatsink and the pump laser for the maximum temperature of quantum wells. Calculations show that the heat transfer coefficient significantly affects the ability of the TEC temperature shift, cooling system performance which is nearly inversely proportional to the heatsink thermal conductivity is not sensitive to its the thickness variation, and the performance of oxygen-free copper with optimization of the area is close to diamond. Meanwhile the maximum temperature of the quantum well has a linear relationship with the pump power, and increasing the pump spot size is an effective way to increase the optical power output
This paper has established a thermal model of Vertical-external-cavity surface-emitting semiconductor laser (VECSELs)
with water-cooled heatsink, calculated the distribution of temperature field with finite element method, and studied the
effects of pumping light, heat transfer coefficient, and heatsink characteristics on the maximum temperature of the
quantum well. Calculations show that there is an optimal heat transfer coefficient value interval, thermal conductivity of
the VECSELs heatsink will have a significant impact on the maximum temperature of the quantum well, and increasing
area of cooler heatsink would help to improve heat dissipation performance. It also shows that the maximum temperature
of the quantum well has a linear relationship with pump power, and a nearly inverse relationship with the spot size. Due
to thermal diffusion of water-cooled heatsink for VECSELs point heat source, the maximum temperature of quantum
well is not sensitive to thickness and area of the heatsink, heat dissipation performance which uses a diamond heatsink is
about 1.7 times the oxygen-free copper heatsink.
It has been demonstrated experimentally that pulsed pumping can significantly improve thermal management, thus upgrade the output power of an optically pumped semiconductor disk laser (SDL). The transient heat conduction equation is solved by the use of the finite element method, and the maximum temperature rise of the active region in an InGaAs quantum well SDL under pulsed pumping is focused. Based on the numerical results, the influences of width, repetition rate, and shape of pump pulses on the maximum temperature rise are discussed, the optimized design of width, repetition rate, and shape of pump pulses are concluded, and the theoretical results are in good agreement with the reported experiments.