High-Brilliance Diode Lasers with Monolithically-Integrated Surface Gratings as Sources for Spectral Beam Combining
Photonex 2013, High Power Diode Lasers and Systems Conference, Coventry, UK, Oct 16-17, pp. 2-3 (2013).
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A high output power and a good beam quality are required for the application of diode lasers for direct material processing. One possible way to increase the output power while keeping the beam quality almost constant is spectral beam combining. The required stabilization of the emission wavelengths of the single emitters can be achieved by the monolithic integration of Bragg gratings into the chips, which is a promising way to reduce fabrication costs in comparison to the utilization of volume Bragg gratings. Higher-order surface Bragg gratings which are particularly favourable with respect to this aspect can be used to fabricate both distributed Bragg reflector (DBR) lasers and distributed feedback (DFB) lasers with varying grating periods. A corresponding DFB laser with a stripe width of 30 µm reached a side mode suppression ratio of 50 dB and an output power of 5.5 W. Aspects of the simulation and the fabrication of the Bragg gratings will be discussed.
Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany