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## 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.