Tree array quantum cascade laser
The monolithic coupling scheme for mid-infrared quantum cascade laser arrays is also investigated with respect to
brightness enhancement. A tree-shaped resonator enables parallel coupling of six laser elements into a single element
by means of several Y-junctions. Phase-locking is observed on the basis of far field analysis, and leads to in-phase
emission on both sides of the device. Figure 2 shows a scanning electron microscope (SEM) image of adjacent Fabry-Perot
and tree array lasers with corresponding dimensions.
SEM picture of a processed tree-shaped QCLs and near field images at different facets