This article describes high beam quality and kilowatt-class diode laser system for direct materials processing, using optical design software ZEMAX ® to simulate the diode laser optical path, including the beam shaping, collimation, coupling, focus, etc.. In the experiment, the diode laser stack of 808nm and the diode laser stack of 915nm were used for the wavelength coupling, which were built vertical stacks up to 16 bars. The threshold current of the stack is 6.4A, the operating current is 85A and the output power is 1280W. Through experiments, after collimating the diode laser beam with micro-lenses, the fast axis BPP of the stack is less than 60mm·mrad, and the slow-axis BPP of the stack is less than 75mm·mrad. After shaping the laser beam and improving the beam quality, the fast axis BPP of the stack is still 60mm·mrad, and the slow-axis BPP of the stack is less than 19mm·mrad. After wavelength coupling and focusing, ultimately the power of 2150W was obtained, focal spot size of 1.5mm * 1.2mm with focal length 300mm. The laser power density is 1.2×10 5 W/cm 2 , and that can be used for metal remelting, alloying, cladding and welding. The total optical coupling conversion efficiency is 84%, and the total electrical -optical conversion efficiency is 50%.

As a pump source for Ti: Sapphire solid-state lasers, the fiber-coupled green diode laser module is critical. However, existing study findings are insufficient to meet the demands of high brightness diode laser pump sources. In this paper, a high brightness green diode laser fiber-coupled system based on TO-can diode lasers is designed. The FACs are installed within the TO-can diode lasers. The optical step as the spatial beam combining system is made up of the HR mirror and the optical wedge. We discussed the relationship between the reflected beam deflection angle and the optical wedge surface inclination angle under the condition of different HR mirror inclination angles. After that, a strategy with appropriate heat dissipation effect is obtained through thermal simulation. Finally, the simulation results verify that couple 18 TO-can single emitters into a 50μm core diameter and 0.22 numerical aperture optical fiber with an output power of 16.9W, the fiber coupling efficiency is 98%. The brightness is 5.66 MW/(cm 2 • Sr) and the module dimension is L 220mm×W 80mm×H 45mm.

KW-class high-beam quality diode laser system was introduced in this paper. In this system, the wavelengths of 808nm, 915nm, 940nm, and 980nm were used for the wavelength coupling and polarization coupling. The wavelength coupling and polarization coupling can reach the optical efficiency of 91.4%. Before wavelength coupling, polarization coupling and beam shaping, the maximum output power of the laser was 1200W, and after that, 1031W was achieved, so the overall conversion efficiency reached 85.9 %. 12mm • mrad of the output beam quality was realized in both the fast axis and the slow axis. Through intelligent control, the diode laser can work in different wavelength, different power and different pulse width. Because of its output power and beam quality, this laser system can be used in the ultra-long-distance laser detection, laser remote sensing and many other demands.

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Abstract.Compared with the traditional cleaning technology, laser cleaning, as a new type of industrial technology, has the advantages of high cleaning rate, green pollution-free and low cost. So laser cleaning is widely used in the fields of paint removal. This paper analyzes that the mechanism of paint removal and heat transfer process in the paint layer and substrate, also determines the process parameters of affect the laser paint removal. The removal of paint from steel substrate with fiber laser of frequency adjustable 20 to 500kHz at 1064nm is reported, researching impact that laser energy density,scanning speed and line width on the paint removal effect. The results show that, the 100μm paint layer can be removed completely while keeping the substrate undamaged with the laser energy density of 10.19J/cm 2 and speed of 4200mm/s and width of 0.02mm. In order to get better results, the cleaning efficiency can be improved by increasing the power, speed and spot size under the right energy density.