Aluminum-free-active-region diode laser achieves 8.8-W CW record at 805 nm
By combining a large optical cavity and an aluminum-free active region, researchers at the University of Wisconsin-Madison (Madison, WI) produced a record-high continuous-wave (CW) output of 8.8 W at 805 nm from a single 100-µm-aperture diode laser. But rather than develo¥a completely aluminum-free structure, the researchers surrounded a 0.015-µm-wide indium gallium arsenide phosphide (InGaAsP) quantum well and an indium gallium phosphide (InGaP) waveguide layer with high-energy-bandga¥indium gallium aluminum phosphide (InGaAlP) cladding layers--providing a dramatic reduction in carrier leakage with consequent improved high-power CW performance.
The InGa¥waveguide was 1 µm thick, while the diode was 1.25 mm long, with 4%/95% facet-coating reflectivities and a 100-µm-wide stripe. Dan Botez, director of the Reed Center at the university, says that the power density of 18 MW/cm2 is more than twice that achievable with AlGaAs devices at 805 nm and virtually the same as for InGaAs active devices at 980 nm. He expects that 805-nm aluminum-free active region structures could be readily made to produce 10 W CW. Such devices pave the way for reliable 60-W CW laser bars, three times more power than can be obtained from AlGaAs laser bars at 805 nm.