A series of optically pumped type-II quantum-well "W" lasers with wavelengt
hs ranging from 5.4 to 7.3 mu m operated at temperatures up to at least 220
K for pulsed operation. The peak output power at 80 K was 1.1 W/facet for
a device emitting at lambda=7.0 mu m. Internal losses were characterized fo
r the temperature range between 40 and 190 K. Auger coefficients determined
from an analysis of the threshold pump intensities were found to be suppre
ssed by up to an order of magnitude compared to type-I III-V semiconductors
with the same energy gaps. (C) 1999 American Institute of Physics. [S0021-
8979(99)05121-X].