High-modulation-efficiency InGaAsP/Si hybrid MOS optical modulator with Mach-Zehnder interferometer

摘要

A high-modulation-efficiency optical modulator integrated on silicon (Si) isa key enabler for low-power and high-capacity optical interconnects. However,Si-based optical modulators suffer from low phase modulation efficiency owingto the weak plasma dispersion effect in Si. Therefore, it is essential to finda novel modulation scheme that is compatible with a Si photonics platform.Here, we demonstrate an InGaAsP/Si hybrid metal-oxide-semiconductor (MOS)optical modulator with a Mach-Zehnder interferometer (MZI) formed by directwafer bonding with an Al2O3 bonding interface. Electron accumulation at theInGaAsP MOS interface enables the extraction of the electron-induced refractiveindex change in InGaAsP, which is significantly greater than that in Si. Thepresented modulator exhibits a phase modulation efficiency of 0.047 Vcm, whichis approximately 5 times higher than that of Si MOS optical modulators. Thisapproach provides a new efficient scheme of phase modulation on a Si photonicsplatform for low-power, high-speed, and high-density optical links.