Design of a high-efficiency U-shape MOS capacitor Michelson interferometer modulator

This work presents a high-efficiency, single-drive U-shape MOS capacitor Michelson interferometer modulator. The introduced U-shape structure enables vertical compression of the optical mode, which significantly enhances the modulation efficiency without compromising series resistance or loaded capacitance. Furthermore, by adopting a Michelson interferometer configuration, the device doubles the effective modulation length through bidirectional light propagation, while maintaining an unchanged capacitance. The designed device achieves a high modulation efficiency of 1.08 V·mm and achieves 50 Gbaud/s operation with an extinction ratio about 2.3 dB under a low 2 V pp drive voltage. The proposed U-shape MOS capacitor modulator reduces reliance on external driver circuits in OIO and CPO transmitters, offering a promising solution for energy-efficient and compact electro-optic modulators.