16 July 2020
EKOLAS project yields high-efficiency, high-performance laser bars
Although the number of infrared light-based applications has increased rapidly in recent years, early manufacturers developed infrared lasers long before infrared light-emitting diodes (LEDs) and vertical-cavity surface-emitting lasers (VCSELs) were used more recently as light sources for facial recognition in smartphones.
In particular, Osram Opto Semiconductors GmbH of Regensburg, Germany has been working for many years on high-power lasers for special applications such as metal processing using welding robots in the automotive industry. Osram, along with its partners, is now presenting results of laser bar performance and efficiency from the latest EKOLAS (Effiziente Konverterlaser) project funded by the German Federal Ministry of Education and Research (BMBF).
In recent years, laser technology has increasingly become an indispensable component of various industries – from medical technology to car manufacturing. The research alliance EffiLAS (‘Effiziente Hochleistungs-Laserstrahlquellen’, or ‘Efficient high-performance laser beam sources’) is focused on securing and further expanding Germany’s technological and economic position in photonics. In regard to the laser light sources, the aim is to further optimize various parameters like performance and energy efficiency.
Together with project partners Laserline, Heraeus, Fraunhofer ILT, fiberware and Welser Profile, Osram Opto has worked on various assignments in the EffiLAS joint project EKOLAS. The main aim was to develop highly efficient infrared laser bars with outstanding output powers and to demonstrate them in industrial materials processing. About 10 years ago, the best laser bars achieved a power of 200W with an efficiency of about 63%. Five years later, an output of 250W at an efficiency of no less than 60% was expected to be the limit of what could be achieved with the existing technologies. Conversion efficiency and cooling limited the output power of lasers at that time. The EKOLAS project, which was completed in February, led to an infrared laser bar with a maximum output power of 400W in continuous-wave operation. With an output of 300W, the bar sets a new standard with an efficiency of about 70% at wavelengths of 1000nm and 1020nm.
The project partners were able to draw on experience gained in other ventures under the EffiLAS umbrella organization including an understanding of materials science and simulation in the field of epitaxy, as well as fundamental expertise in chip and facet technologies.
“We are very excited to achieve, and in some cases even exceed, all of our targets in this project,” says Sebastian Hein, EKOLAS project manager at Osram Opto. “The key to success was the development of innovative software tools for simulating the electro-optical properties of the lasers, which take into account the thermal distribution, temperature-dependent material properties and mode-dependent wave propagation in the resonator. These tools considerably accelerated and simplified the necessary test runs, making a fundamental contribution to the results of the project.”
The newly gained knowledge from the simulation of certain processes can now be transferred to other product groups and wavelengths in the range 800-1060nm.