MADISON, WI—Diode-laser manufacturer Alfalight says it has achieved a world record for power conversion in high-power diode-laser bars. At the annual meeting of the Lasers and Electro-Optics Society (Nov. 7–11, Puerto Rico), Alfalight VP of R&D Manoj Kanskar reported 71% power conversion efficiency (PCE) at 25 ∞C for a 50-W, 976-nm laser bar. This improves on the company's previous record of 65% PCE for a 4-W single emitter. The work was done with support from the Defense Advanced Research Projects Agency (DARPA) Super High Efficiency Diode Sources (SHEDS) program.
"Alfalight has now established the benchmark for high-power diode laser efficiency," said Tom Earles, chief technology officer of Alfalight. "We will integrate these high-efficiency aluminum-free active-region (ALFA) diode laser designs into our next generation of commercial products."
According to the company, the new level of efficiency was achieved by examining sources of loss in the ALFA diode lasers and working to reduce each of those losses. Advances were made in increasing the efficiency of carrier injection into the quantum well through bandgap engineering, altering the confinement structure to decrease the laser's operating voltage, and reducing the losses from scattering and absorption of lasing photons through waveguide adjustments.
Alfalight is now working toward a goal of 80% PCE for the DARPA SHEDS program by September 2006. This work is expected to involve trying to confine the carriers in two or three dimensions using more aggressive techniques.
Other U.S.-based companies working under SHEDS, including nLight Photonics and JDS Uniphase, have also developed laser devices with efficiencies of around 70%.