20-W CW power barrier surpassed for 975-nm diode-laser chip

Researchers at Alfalight (Madison, WI) have demonstrated 22 W of continuous-wave (CW) power from a single (100-µm)-stripe 975-nm-emitting diode-laser chip at a 25ºC heat-sink temperature. This result demonstrated 47% higher power than the previously reported best for any multimode diode-laser pump in the wavelength range of 900 to 1000 nm. The electrical-to-optical power-conversion efficiency (PCE) and the characteristic temperature, T1, which governs the temperature sensitivity of external differential quantum efficiency, limit the highest achievable power.

The Alfalight researchers have significantly improved both the PCE as well as the T1 to hit this record-high CW power. The 22-W power was achieved with a 3-mm-long chip that was bonded p-side down on a copper heatsink with indium solder. At this power level, the devices thermally “rollover” (saturate) and do not suffer from catastrophic optical-mirror damage. Peak PCE was measured to be 68%. Contact Manoj Kanskar at [email protected].