Hochleistungsdiodenlaser und diodengepumpte Festkoerperlaser. Thema: Optische und thermische Eigenschaften von Hochleistungslaserdioden Abschlussbericht

Abstract

Investigations of optical and thermal properties of high power laser diodes (HLDs) provided a lot of new results for achieving a better diode performance by using the knowledge of optimization of the semiconductor structure and the thermal architecture of diode laser. Theoretical modeling was done for obtaining better understanding of the interaction between thermal and optical processes in laser diodes in particular in the facet region. The calculated temperatures of the laser facets for certain operation parameters were in good agreement with the data obtained in micro-Raman facet temperature measurements. Further theoretical and experimental results were achieved on the catastrophical optical damage (COD) mechanism in the facet region. Finite Elemente Modeling (FEM) was used to investigate the influence of different structure and material parameters e.g. layer thickness, material composition, doping concentration, and parameters of the thermal architecture on the thermal behavior of the diodes. The transient temperature behavior of high power laser diodes was monitored for different mounting configurations. The diode behavior from ns pulses up to cw-operation was measured in detail. Nondestructive methods have been developed for both strain characterization and defect estimation. A new optical scanning technique based on photocurrent spectroscopy was developed successfully to find out local weakpoints upon aging. With the near-field scanning optical microscopy (NSOM) technique these processes were characterized in sub-#mu#m region. Fourier transform spectroscopy was used to obtain the rise of the defect concentration and the levels depths of the defect created upon aging. (orig.)SIGLEAvailable from TIB Hannover: F98B470+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman