Design for high-speed and high-extinction ratio electroabsorption modulator (EAM) has been presented and reviewed. Based on waveguide structure, reducing both parasitic capacitance and cladding impedance can enhance the microwave performance and bandwidth of EAM.
With selective undercut etching active region, low optical as well as microwave loss can be attained to further improve EAM modulation. By applying high band offset ratio in quantum well, EAM active region, strong exciton and high carrier confinement enlarge the modulation efficiency.