Design of a 10 kW level diode laser optical stack with a line shape beam spot.

Abstract

We designed and simulated a diode laser with output power of more than 10 kW and a line shape beam spot of approximately ${14 - 58}\;{\rm mm} \times {1.6}\;{\rm mm}$14-58mm×1.6mm (${{\rm 1/e}^2}$1/e2 width). The diode laser was assembled with high fill factor diode laser bars that can be cooled with filtered tap water. The diode laser bar was beam shaped with a tilted cylindrical lens array to twist the slow axis of individual emitters by 90 deg, and then the slow axis was collimated with a single cylindrical lens. From the simulation, 20 laser diode bars with the same wavelength formed a diode laser optical stack with an output power of more than 3.5 kW, a beam spot of ${31}\;{\rm mm} \times {12}\;{\rm mm}$31mm×12mm size, and full divergence angles of around 6 mrad in both the horizontal and vertical directions. Then, three laser diode optical stacks with different wavelengths were wavelength-multiplexed to obtain an output power of more than 10 kW. Finally, the diode laser optical stack was transformed by simple cylindrical lenses to form a line shape spot with a working distance longer than 250 mm. Our diode laser design is much simpler than previous devices with similar output power and can find various applications such as high-speed laser cladding.