High power semiconductor laser diodes

In the last decade the output power of semiconductor laser diodes has increased dramatically. Starting from a power range of several milliwatts, which is sufficient for a range of mass applications in the field of optical communication and optical storage systems, now semiconductor laser systems with an output power in the kilowatt range are available. The progress in the development of high-power edge- and surface-emitting lasers emitting is described. The sophisticated design of large optical cavity lasers, the advanced production and mounting technology lead to usable cw-ouput powers in the range up to 70 W for a single laser bar. The concept of the monolithic vertical integration of several lasers leads to nanostack lasers with high power capabilities under short and long pulse operation. Vertical emitting lasers (VCSEL) also show promising high power performance. The main advantage of diode lasers are the small volume, the high overall efficiency up to 60%, the availability of a wide spectral range and the high reliability. This combination together with the high output power opens a wide field of applications covering e. g. pumping of solid state lasers and amplifiers, transfer to printing plates, soldering and direct machining.