Highly Efficient High-Brightness 970-nm Ridge Waveguide Lasers

• Published in: IEEE photonics technology letters Vol. 32; no. 7; pp. 406 - 409
• Main Authors: Wilkens, Martin, Erbert, Gotz, Wenzel, Hans, Maabdorf, Andre, Fricke, Jorg, Ressel, Peter, Knigge, Andrea, Crump, Paul
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: adiabatic taper; Brightness; Diode lasers; Efficiency; Energy conversion efficiency; high brightness; high efficiency; Laser beams; Laser modes; Lasers; Measurement by laser beam; Optical waveguides; Power lasers; ridge waveguides; Waveguide lasers
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2020.2978243

In this letter we present new results on high power 970 nm ridge waveguide lasers based on an extreme double asymmetric epitaxial design. Due to an improved lateral-longitudinal design an M 2 -value below 1.1 and efficiency over 60% could be maintained at power levels slightly above 2 W. The lasers consist of a narrow mode-filter section at the back facet, a relatively broad section at the front facet for high power capability, and a tapered section in between with a very small taper-angle. We achieved the highest reported conversion efficiency for 1 W single lateral mode power to date of 67%, as well as the highest lateral (linear) brightness of 7.5 W/mm · mrad with 55% efficiency at 2.5 W. Results of first life time tests are presented which show the potential for commercial use.