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

TL;DR

This paper presents an InGaAsP/Si hybrid MOS optical modulator with a Mach-Zehnder interferometer that achieves significantly higher phase modulation efficiency than traditional Si modulators, enabling low-power, high-speed optical interconnects.

Contribution

The paper introduces a novel InGaAsP/Si hybrid MOS optical modulator with direct wafer bonding that significantly improves phase modulation efficiency on silicon photonics platforms.

Findings

Phase modulation efficiency of 0.047 Vcm, five times higher than Si MOS modulators.

Electron accumulation at the InGaAsP MOS interface enhances refractive index change.

Demonstrates a compatible, efficient modulation scheme for silicon photonics.

Abstract

A high-modulation-efficiency optical modulator integrated on silicon (Si) is a key enabler for low-power and high-capacity optical interconnects. However, Si-based optical modulators suffer from low phase modulation efficiency owing to the weak plasma dispersion effect in Si. Therefore, it is essential to find a 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 direct wafer bonding with an Al2O3 bonding interface. Electron accumulation at the InGaAsP MOS interface enables the extraction of the electron-induced refractive index change in InGaAsP, which is significantly greater than that in Si. The presented modulator exhibits a phase modulation efficiency of 0.047 Vcm, which is approximately 5 times higher than that of Si MOS optical modulators. This approach provides a new efficient scheme of phase modulation on a Si photonics platform for low-power, high-speed, and high-density optical links.