GeSi modulator based on two-mode interference

A GeSi modulator based on two-mode interference is designed in this study. A GeSi layer with a height of 0.22 μm is introduced to decrease the optical power overlap of the two modes. A doping region in which the free carrier plasma dispersion effect exists to change the oscillation period for on- and off-state switching is identified. A doping concentration of 1×1018 cm−3 for both n and p type is selected. The single modulation arm for 3 V operation is 1416.3 μm long. The extinction ratio and insertion loss are 15 and 5 dB, respectively. The traveling electrode design shows 3 dB bandwidth as large as 50 GHz.