The Investigation Of Thermal Characteristics On High Laser Damage Threshold Of Semiconductor Laser Facet Coating

This thesis focus on thermal characteristics analysis and preparation of semiconductor laser facet coating. For high laser damage threshold of semiconductor laser facet coating requirements, The mainly study are following as:1. As808nm semiconductor laser for example, the model of semiconductor laser facet heat distribution is established which combined heat and thermal conduction mechanism theory. Through analyzing the heat exchange process of facet and coating, as well as the semiconductor laser internal heat generating mechanism. When at high temperature it can get the heat source distribution of high power semiconductor laser facet.2. Analyzes the semiconductor laser facet catastrophic optical damage mechanisms and coating damage mechanisms, the process of COD and influence on device characteristics are established. Combined with the carrier density diffusion equation and the photon density distribution model to investigate the location of COD. And analyzes the thermal effects damage and field effect damage of thin film, in order to avoid the occurrence of COD on the cavity surface.3. Investigate the high laser damage threshold cavity surface processing technology, including vacuum cleavage, cavity surface passivation, high damage threshold coating. To suppress the cavity surface oxidation, reduce the density of surface state, decrease the radiative recombination, in order to improve COD threshold. Considering thermal effects damage and field effect damage, optimal design two coatings which ZnSe and diamond material as cavity surface passivation coating respectively.4. According to the heat generating mechanism and heat distribution of high power semiconductor lasers. Using ANSYS finite element software to simulate the steady state temperature characteristic of devices which:(1) unpassivated;(2) coated with ZnSe passivation layer;(3) coated with diamond passivation layer, and get the steady state temperature distribution of each laser device.5. The coatings are prepared with electron beam deposition and microwave plasma chemical vapor deposition, which the facet of808nm high power semiconductor laser is coated with:(1) ZnSe passivation layer (2) diamond passivation layer. The results of device characterization test shows that the output optical power of device which coated with ZnSe passivation layer is3.1W, and the COD threshold is reached3.1MW/cm2; the output optical power of device which coated with diamond passivation layer is3.7W, and COD threshold is reached3.7MW/cm2.