Electroabsorption and saturation behavior of InGaAsP/InP/InAlAs multiple superlattice electron transfer optical modulator structures

We report substantial progress in the growth of multi-quantum-well electron transfer optical modulator structures by metalorganic vapor phase epitaxy, which is made possible as a consequence of the highly abrupt modulation doping of donors and acceptors in InP-reservoir and InAlAs-barrier layers, respectively. Due to a large thermionic emission barrier provided by the type II InP/InAlAs interface, the InGaAsP/InP/InAlAs devices exhibit extremely low leakage current densities. We observe distinct and sharp features related to absorption quenching in differential transmission spectroscopy. Moreover, the saturation intensities of electron transfer modulators are determined. The underlying physical mechanism is discussed.