Capture and confinement of light and carriers in graded-index quantum well laser structures

We investigated graded-index separate-confinement heterostructure lasers and compared their performance with a conventional quantum well laser by using Raman and time-resolved photoluminescence spectroscopy. We found that grading the index of the Ga1−xAlxAs/GaAs waveguide and increasing the Al content improves considerably both, the light and carrier trapping and reduces carrier escape from the active region.