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Proceedings Paper

Fiber-coupled air-cooled high-power diode laser systems
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Paper Abstract

Current laser systems based on high-power laser diode bars need active cooling either water cooling or the use of thermo-electric coolers to ensure an adequate operating temperature for a reasonable lifetime. Here is a solution with a bonded fin heat sink and forced ventilation introduced, a diode laser bar with an improved efficiency and a low thermal resistance as well as an optical system for a highly efficient fibre coupling. With this system it is possible to couple 25 Watt continuous wave power from a single laser diode bar on a passive heat sink into a fibre with 200 μm core diameter. The basis for this performance is a heat sink with an exceptionally low thermal resistance. Several new features are introduced to reach a low overall gradient between the laser diode temperature and the ambient temperature. In addition, it does geometrically fit to the layout of the optical design. Shape and aspect ratio of both heat sink and housing of the laser system are matched to each other. Another feature is the use of hard-soldered or pressed bars to achieve a thermo-mechanically stable performance. The long-term thermal characteristic was tested. The operation temperature comes to saturation after about 30 minutes. Therefore it can be used for continuous wave operation at 25 Watt output power. At a quasi continuous operation at 70 percent duty cycle a peak power of 30 Watt out of the fibre is possible. From this technology results a compact fibre coupled laser system what is simple to drive compared with current high power laser systems, because there is no need to control the operating temperature. This gives way for more compact driver solutions. Fields of application are laser marking systems and material processing, where a simple driver system is requested. Also medical applications need this requirement and a compact cooling too so that mobile integrated solutions become possible. Further developments allow multiple laser diode systems for specific industrial applications demanding more power. Our measurements show the potential for direct air-cooled laser systems with 100 Watt power out of the fibre.

Paper Details

Date Published: 13 February 2008
PDF: 9 pages
Proc. SPIE 6876, High-Power Diode Laser Technology and Applications VI, 68761M (13 February 2008); doi: 10.1117/12.763199
Show Author Affiliations
Daniel Bartoschewski, LIMO Lissotschenko Mikrooptik GmbH (Germany)
Jens Meinschien, LIMO Lissotschenko Mikrooptik GmbH (Germany)
Udo Fornahl, LIMO Lissotschenko Mikrooptik GmbH (Germany)

Published in SPIE Proceedings Vol. 6876:
High-Power Diode Laser Technology and Applications VI
Mark S. Zediker, Editor(s)

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