Efficient modeling of the optical properties of MQW modulators on InGaAsP with absorption edge merging

The optical properties of quantum wells on Ga_xIn_1-xAs_1-yP_y are investigated. The dielectric function ε(ω) is calculated with a density matrix formalism valid for excitonic transitions as well as for the interband absorption including band mixing. With two simple approximations, the required number of overlap integrals is greatly reduced, allowing a fast and efficient exciton calculation. The calculated results are compared with measurements at 77 K and at a room temperature of 300 K. Furthermore, we present a field-induced heavy and light hole absorption merging for a Ga_xIn_1-xAs_1-yP_y-based modulator for the first time. It can he operated at a wavelength λ=1.55 μm, showing a very large absorption change and a small negative chirp factor, which is recommended for a low bit error rate