Research On High Brightness All-solid-state Diode Pumped Solid-state Laser

High power diode laser is the requirement to research on the high-average-power diode-pumped solid-state lasers, so the package techniques of the diode laser is studied first in this thesis. Heat dissipating and cooling of,the diode bar is the key technique in the high power diode laser package. Based on the structure and emission characteristic of the diode bar, a numerical calculation .model of the thermal dissipation was proposed and a related simulation of the effects of heatsinks parameters on the performance of the packaged laser was carried out. The calculated results are consistent with the experimental data, and demonstrate that the model is reliable and helpful to design the reasonable package. The packaging experiments of linear array diode laser were carried out. The output power of 100W with duty cycle of 20% is achieved in Q-CW mode, the life time of which reaches 2.19 109 shots. At the same time, the CW 40W diode laser is successfully packaged. The FWHM of the spectral profile is less than 3nm and the E-O efficiency is about 40%.Based on the different requirements on the operating mode, the back surface cooling package style by impinge cooler and the module package style by micro-channels coolers were studied respectively. The liquid cooler with high cooling efficiency is the key techniques in high-average-power 2D-stackes package. A numerical calculation model of the cooling efficiency of the cooler was built and the numerical simulation was carried out by ANSYS finite element program. The structure of the cooler is optimized according to the calculated results. Oxygen-free copper serves as the cooler, the channels and the layers of which are cut and soldered into whole body by the conventional line-cutting and soldering techniques, so the difficulties and costs to fabricate the cooler were reduced. The developed cooler for the packaging experiments has the dimension of 0.15mm~0.2mm width, 0.3mm~lmm depth and 1.5mm thickness, the thermal resistance of which is ~0.3 /W. A CW 2D-stacks array with 1kW output power is experimentally packaged using the copper micro-channels cooler. The central wavelength of 808nm, FWHM of 2.2nm and E-O efficiency of 45% are achieved. Most of the experimental results about high-average-power diode laser package have not been reported in previously published paper in this field.An accurate model to calculate the laser gain distribution within the laser medium is proposed and an analysis model of thermal effect with varied parameters is deduced. The calculated results were verified by ANSYS finite elements program. A numerical simulation and the design of the diode pumped module of Nd:YAG rod were carried out. An amplified pump module with a peak power of 6500W and duty cycle of 12.5% was developed successfully. The experimental results demonstrated that the module have uniform gain distribution and an average small signal gain coefficient of 0.22cm-1~0.28cm-1, which accorded with the calculated results.Under consideration of the effects of the life time of Nd: YAG lower level on extracted energy from amplifier, a numerical model and calculation program incorporated the effects of the pulse width on amplifier energy extraction is proposed. The calculated results are compared with the experimental data of a slab MOPA DPL system setup previously and then the model is modified according to experimental results. A numerical simulation was carried out to study and design 1J MOPA DPL amplifier. At the same time, the experiment of multimode crystal fiber to improve the beam quality of MOPA DPL with high repetition rate and narrow pulse width were carried out in this paper. The experimental results show that the fiber phase conjugator can compensate for the beam distortion cased by thermal effects of amplifier and 60% SBS reflectivity can be reached. More than 85% reflectivity is achieved further by a taper fiber. The design thought of increasing SBS reflectivity by taper fiber is proved experimentally.A numerical simulating of the laser performance of the laser...