High average power quantum cascade lasers at 9.3 mum using InP top cladding
layers and both junction up and junction down mounting are presented. A 3
mm long, junction up mounted device emitted 54 mW average power at 30 degre
esC and 11.5% duty cycle with a threshold current density of 3.72 kA/cm(2).
A similar, but only 1.5 mm long device with high reflection coating on bot
h facets was mounted junction down and tested at even higher duty cycles. A
t -27 degreesC, we achieved continuous wave operation with a threshold curr
ent density of 3.3 kA/cm(2). (C) 2001 American Institute of Physics.