The development of diode lasers started about 40 years ago with low power devices which were operated at cryogenic temperatures. Since then diode lasers made great progress in power, lifetime and costs. Some of the first widespread applications like tele-communication and home entertainment used the advantage of narrow line width and compactness, rather than efficiency and power. Especially in the last decade, great improvements were made in terms of output power as well as in costs of operation. From about 10W per 1cm laser bar 15 years ago, they have developed to 150W for continuous operation recently. In the same time, the price dropped from about 100$/W to little over 2$/W today. Besides chip technology, new technologies for packaging were developed and experiences with high power electronic devices and telecom lasers helped introducing cost efficient and highly reliable devices for industrial use.
These achievements enabled a breathtaking development of this technology and generated a wide variety of industrial applications. Today, diode lasers offer many advantages over other laser systems which further favour this technology.
The development of laser bar as well as packaging will be reviewed. Advantages and areas for further optimizations as well as examples for industrial application of diode lasers will be given. An outlook on what will be available in the near future will finish the talk.