Multi-quantum well electro-optic modulator using a combination of excitonic index and absorption changes

Efficient reflection modulation, using index and absorption changes in a novel p-i-n surface-normal Fabry-Perot resonator configuration, is reported. A reverse bias changes both the absorption and the index of refraction by a tuning of the exciton resonance. In the resonator configuration, these effects cause both a shift in the position of the Fabry-Perot modes and a change in its Q, which can combine to enhance the net change in modulator reflectivity near the exciton lines. Further away from these exciton lines, the Fabry-Perot modes tune purely by index modulation