Study Of Novel Semiconductor Lasers' Thermal Property And The Optimization Of Conventional Quantum Well Lasers

High power semiconductor lasers are widely used in communication, surgery, military, printing and optical pump. But for traditional laser, the output optical power, which is increased by increasing the injecting current, will be limited by the electro-thermal destroy and the catastrophic optical damage (COD) at high optical power. The high efficiency and high power semiconductor laser with multi-active regions, which are cascaded by reverse biased tunnel junction(s) can resolve the problems in theory and overcome these shortcomings. But for high power semiconductor lasers, the heat produced in operation make a crucial role. Studying on InGaAs/GaAs/AlGaAs quantum well laser, the main content are as following:1. The work mechanism of the novel laser is introduced, and the math expression of efficiency is given, and the lasing mode and the distribution of the optical field are simulated. It proves that for the novel laser, the inner quantum efficiency is larger than l, and at the same injecting current compared with the normal laser; the output optical power is higher. The data of the novel 4-active region laser at 2A current are listed: output power 4.435W, inner quantum efficiency 3.5, slope efficiency 2.97W/A.2. Analyze the effect of the heat produced in operation on the performance of the laser by measuring the electrical and optical parameters. The heat sources are analyzed in theory and calculated under some hypothesis. A thermal conductive model is built and by solving the model equation, the numerical values of the 1-active region laser, 2-active region laser, 3-active region laser and 4-active region laser are obtained. The dynamical temperature distribution plots are obtained, too. When the number of the active region is added, the thermal properties of the novel laser become bad. It must be improved.3. In order to obtain good ohm contact, the experimental project is designed by adopting Kelvin photochart. The sheetary contact resistances of the samples are measured under ali kinds of condition, such as different substrate growing temperature, different alloy temperature, different alloy time and different metal contact. The sheetary contact resistance is smaller; the ohm contact resistance is smaller. Good ohm contact resistance can make the differential resistance of the laser small and the test results of the lasers, which are produced under the optimal conditions, prove it.4. For our laboratory is changing toward industrialization, a lot of work on conventional InGaAs/GaAs/AlGaAs quantum well laser has been done. How the parameters, such asthreshold current density, slope efficiency, FWHM and spectrum width, are influenced and how much the influence is, are discussed by the numbers. The effective means how to improve a certain performance parameter are purposed too. In our practice work the kinks on P-I curve and the multi-petals on far field divergence have happened. We find the reason through theory analysis and improve on it. The result is good and the problems are resolved.