Double-layer graphene on photonic crystal waveguide electro-absorption modulator with 12 GHz bandwidth

Zhao Cheng,Leif Katsuo Oxenløwe,Lars Hagedorn Frandsen,Hao Hu,Sanshui Xiao,Michael Galili,Xiaolong Zhu,Jianji Dong,Xinliang Zhang,Yunhong Ding

doi:10.1515/nanoph-2019-0381

Abstract

Abstract Graphene has been widely used in silicon-based optical modulators for its ultra-broadband light absorption and ultrafast optoelectronic response. By incorporating graphene and slow-light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double-layer graphene electro-absorption modulator in telecommunication applications. The modulator exhibits a modulation depth of 0.5 dB/μm with a bandwidth of 13.6 GHz, while graphene coverage length is only 1.2 μm in simulations. We also fabricated the graphene modulator on silicon platform, and the device achieved a modulation bandwidth at 12 GHz. The proposed graphene-PhCW modulator may have potentials in the applications of on-chip interconnections.

Highlights

High-speed optical communications demand large bandwidth and low power consumption in future growing data traffics
Graphene has been widely used in silicon-based optical modulators for its ultra-broadband light absorption and ultrafast optoelectronic response
By incorporating graphene and slow-light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double-layer graphene electroabsorption modulator in telecommunication applications

Summary

Introduction

High-speed optical communications demand large bandwidth and low power consumption in future growing data traffics. The light interference type intensity modulators, achieved by controlling the real part of silicon permittivity to generate a phase change, are typically designed by micro-ring resonators [4, 5] or Mach-Zehnder interferometers (MZI) [6,7,8]. They require either a precise fabrication method or a large footprint on the chip, which restricts their integration on large scale circuits. To meet the requirement of high-speed and low-energy consumption for the next-generation communication systems, a compact integrated electro-optical modulator with a large bandwidth and modulation depth (MD) is needed

Objectives

Discussion

Conclusion