Saturated Layer Gain in Waveguides With InGaAs Quantum Well-Dot Heterostructures
Modal absorptions in laser-like heterostructures containing
InAs self-assembled quantum dots (QDs) and InGaAs
quantum well-dots (QWDs) have been studied. The evaluation
of photoresponse as a function of waveguide length has allowed
us to determine per-layer modal absorptions of 69 and 13 cm-1
for the ground state optical transitions of QWDs and QDs, respectively.
The values of the modal absorption can be used as
a measure of the maximal (saturated) modal gain. To compare
quantum heterostructures with different dimensionality we have
introduced the layer gain constant, a parameter characterizing the
light transmittance through the absorbing or gaining layer. We
have shown that theQWDlayer gain constant significantly exceeds
quantum well and quantum dot ones.