400 µm stripe lasers for high-power fiber coupled pump modules
High Power Laser Sci. Eng., vol. 1, no. 1, pp. 60-67 (2013).
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We present a 940 nm quasi-continuous wave semiconductor laser designed as a building block for high-power fiber coupled pump modules. The laser comprises a 400 µm narrow-stripe array mounted on an aluminum nitride substrate using hard solder. The chip has been optimized for high optical power and low lateral far-field angles. Two vertical and six lateral structure variations have been investigated to determine the best achievable performance. Operating at 1 ms pulse width and a repetition rate of 10 Hz, the laser device reaches a maximum pulse power of 86 W from a 400 µm aperture and more than 62% maximum conversion efficiency. Low lateral far-field angles (95% power enclosed) of 11.5° and 13.5°, depending on the epitaxial design, enable efficient multimode fiber coupling. The potential for highly reliable applications has been demonstrated.
1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
2 University of Applied Sciences Munich, Lothstraße 34, 80335 Munich, Germany
diode laser; high-power laser array; optical fiber coupling