High-Efficiency of Narrow-Width MOS Capacitor Type Si Optical Modulator with TM Mode Excitation

Abstract

We developed a high speed and high efficiency of a narrow-width metal-oxide-semiconductor (MOS) capacitor type Si optical modulator (Si-MOD) by applying TM optical mode excitation. We designed and fabricated the mode-converter from TE to TM mode for MOS capacitor type Si-MOD. Even in case of 200-nm width rib-waveguide, Si MOS-MOD with TM mode showed high-modulation efficiency of 0.17 Vcm and smaller electrical capacitance with decrease in MOS junction width. We also demonstrated 40 Gbps operation for 30–60 μm-long Si MOS-MOD with TM mode.