Short-pulse lasers delivering a high output power along with a high repetition rate are highly requested in novel applications such as X-ray generation, and for studies into laser-induced fusion systems for future energy production. Up to now, the key figures of short-pulse lasers, high power and high repetition rate, are usually limited to either one of these features. Now, such a powerful light source offering both characteristics has been developed within a joint project by the FBH and the Max Born Institute (MBI). The MBI is responsible for the overall system, an optically pumped solid-state disk laser, whereas the FBH develops the required pump modules. Each module consists of 56 laser diodes closely arranged together which deliver an overall pump energy of 6 J with a 200 Hz repetition rate. To couple the single laser beams into a glass fiber with highest efficiency, a relatively simple setup could be used due to FBH-made customized chips and a newly developed mounting technology which allows a laterally coupled heatsink. The power conversion efficiency at working point is over 60% and a coupling efficiency of more than 90% was achieved.
Further information regarding FBH's stack developments.
W. Pittroff, B. Eppich, G. Erbert, R. Platz, D. Tyralla, G. Tränkle, "Simple design for fiber coupled 9xx nm kW- QCW pump module with high duty cycle based on customized chips and lateral heat removal", Proc. SPIE, vol. 8965, Photonics West, San Francisco, USA, Feb. 1-6, 896515 (2014).
R. Platz, B. Eppich, P. Crump, W. Pittroff, S. Knigge, A. Maaßdorf, and G. Erbert, "940nm Broad Area Diode Lasers Optimized for High Pulse-Power Fiber Coupled Applications", IEEE Photonics Technol. Lett., vol. 26, no. 6, pp. 625-628 (2014).