Osram broad-area IR laser diode sets new lab record for brilliance

4.8 W/(mm*mrad) brightness enables 10% increase in pump-module output power for fiber-laser pumping.

Osram broad-area IR laser diode sets new lab record for brilliance
Osram broad-area IR laser diode sets new lab record for brilliance
Prototype of a high-power laser bar, as developed by Osram Opto Semiconductors in the IMOTHEB project. (Image: Osram)

Osram Opto Semiconductors (Munich, Germany; ISIN: DE000LED4000; WKN: LED 400; trading symbol: OSR) has produced a broad-area infrared laser diode with a lateral brilliance of up to 4.8 W/(mm*mrad) in the laboratory. Brilliance (or brightness) is a measure of the combination of optical output power and beam quality; the more brilliant the laser, the more optical power it can inject into an optical fiber of the same size. This then increases the output power of modules for pumping fiber lasers used for materials processing.

The outcome is one of the results of a now-completed project called "Integrated microoptical and microthermal elements for diode lasers of high brilliance" (IMOTHEB), coordinated by Osram and funded by the German Federal Ministry of Education and Research. The other two project partners were DILAS Diodenlaser (Mainz, Germany) and the Max Born Institute (Berlin, Germany). The project ran from October 1, 2012 to September 30, 2015.

Improved microthermal and micro-optical elements
A lateral brilliance of up to 4.8 W/(mm*mrad) was achieved in the laboratory, one of the highest known values for broad-area laser diodes. Optimization of the chip design provided the basis for this success, particularly the integration of microthermal and micro-optical elements for beam shaping on the chip.

One aim of the IMOTHEB project was to further develop laser chips so that they delivered greater optical output power with constant beam quality. One of the project partners, the Max Born Institute, provided considerable support for the chip-development work in the form of extensive methodologies and analyses. The findings from the project will flow into product development.

10% boost in pump-module output power
An important application of fiber-coupled lasers is the pumping of high-power lasers for materials processing. Fiber lasers in particular are gaining in importance, for example for cutting and welding sheet metal in the automobile industry. At the same time, there is growing pressure on costs. Another aim of IMOTHEB was therefore to reduce the system costs for such pump modules.

Project partner DILAS Diodenlaser researched concepts for the automated assembly of laser diodes. DILAS also used a demonstration module to show that the improved Osram chips increased the output power of the module by 10%.

The IMOTHEB research project (FKZ 13N12312) began in October 2012 and was supported by the German Federal Ministry of Education and Research (BMBF) as part of the "Integrated Microphotonics" initiative. Osram Opto Semiconductors coordinated the project.

For more info, see www.osram.com.




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