Study of waveguide absorption in InGaAs ”quantum well-dots” heterostructures

Abstract Electronic states in a novel type of quantum-size heterostructures referred to as InGaAs quantum well-dots (QWDs) were experimentally studied using absorption in stripe waveguides of different lengths based on a single, double, five, and ten QWD layers. The value of the modal absorption was measured to be 70 cm−1 and 90 cm−1 for ground-state transition and high-energy one, respectively. The structure of electronic states in the QWDs is also analyzed by polarization-resolved waveguide absorption and the dependence of a polarization degree on the chip length is discussed. TM polarization of the heavy-hole-based optical transition photoresponse observed in the long waveguides is attributed to the light depolarization due to the scattering on the QWD heterointerfaces.