Study On High Power Diode Laser With Beam Shaping And Beam Combining

As application potential of diode lasers in production processes and military, the developed countries have attached considerable importance to the development of high power diode lasers, and developed some programs and plans, such as Germany's "BRIOLAS" ( Brilliant Diode Lasers ) program, the European "WWW.BRIGHTER.EU" (World Wide Welfare: high BRIGHTness semiconductor lasER for gEneric Use)plan, the U.S. "SHEDS"(Super High Efficiency Diode Sources), "ADHELS"(Architecture for Diode High Energy Laser Systems) program. The main research object of these programs and plans are to the enhancement output power and increase the brightness of diode lasers. The lasing wavelength of semiconductor lasers has been greatly expanded, covering the ultraviolet, visible, infrared, mid-infrared, even to the THz band.In the practical application, the brightness of diode laser in place of output power becomes an important factor. The output power of a single diode laser stack arrays can not meet the actual demand, which requires improve the output power and brightness of diode laser. Multiple diode laser can be coupled into a laser beam with directly output or with fiber coupled. It is a critical issue which kinds of beam coupling technique used to achieve high brightness and high beam quality. Better brightness and higher output power of diode laser can be achieved by beam shaping.In this paper, according to the optical and mechanical design,a set of 880nm high power diode laser system is demonstrated with Beam Parameter Product (BBP) of 79.3 mm mrad×81.2 mm mrad, electro-optical conversion efficiency of more than 45% and continuous output power of 1 kW. With polarization combination and the beam shaping technology, 808nm diode laser system is demonstrated with continuous output power of 2600W, which is not yet reported. The designed beam shaping and beam segmentation technique are also used to rearrange and balance the beam quality of fast and slow axis of the diode laser beam. Dual wavelength 1kW diode laser is obtained with the Beam Parameter Product of 17.5mm mrad×17.5 mm mrad, which is not yet reported.This paper is divided into seven chapters. Chapter 1 is the introduction, which describes the application of high power diode lasers and the development status. In Chapter 2 the basic principles of high power semiconductor laser is described and the output characteristics of high power diode laser is analyzed. In Chapter 3 beam shaping technology and design is described. In Chapter 4 the diode laser beam collimation, laser "smile" effect of the laser beam quality is described. In Chapter 5 high power diode laser stack beam shaping design is demonstrated. In Chapter 6 high-power diode laser Beam shaping and experimental design with variety of method to improve the brightness of diode lasers is studied. The final Chapter is the summarition and expectation.