Integrated ultra-high-performance graphene optical modulator

TL;DR

This paper presents a graphene-based optical modulator integrated on Silicon photonics that achieves 60 GHz speed, high efficiency, and compact size, advancing high-density, energy-efficient photonic integration.

Contribution

It introduces a novel double-layer graphene modulator with a vertical cavity, significantly improving speed, efficiency, and size compared to previous modulators.

Findings

Achieves 60 GHz modulation speed with 3 dB roll-off.

Reduces driving voltage by 40 times using a cavity.

Maintains 5.2 dB/V modulation depth with high efficiency.

Abstract

With the increasing need for large volumes of data processing, transport, and storage, optimizing the trade-off between high-speed and energy consumption in today's optoelectronic devices is getting increasingly difficult. Heterogeneous material integration into Silicon- and Nitride-based photonics has showed high-speed promise, albeit at the expense of millimeter- to centimeter-scale footprints. The hunt for an electro-optic modulator that combines high speed, energy efficiency, and compactness to support high component density on-chip continues. Using a double-layer graphene optical modulator integrated on a Silicon photonics platform, we are able to achieve 60 GHz speed (3 dB roll-off), micrometer compactness, and efficiency of 2.25 fJ/bit in this paper. The electro-optic response is boosted further by a vertical distributed-Bragg-reflector cavity, which reduces the driving voltage by about 40 times while maintaining a sufficient modulation depth (5.2 dB/V). Modulators that are small, efficient, and quick allow high photonic chip density and performance, which is critical for signal processing, sensor platforms, and analog- and neuromorphic photonic processors.