Experimental verification of electro-refractive phase modulation in graphene

TL;DR

This paper experimentally demonstrates electro-refractive phase modulation in graphene integrated with silicon waveguides, providing key parameters and design guidelines to enhance on-chip opto-electronic devices.

Contribution

It presents the first experimental verification of graphene's electro-refractive phase modulation at telecom wavelengths with detailed parameter extraction and simulation validation.

Findings

Effective refractive index change measured in graphene modulator

Insertion loss and absorption change characterized

Design guidelines for graphene-based phase modulators provided

Abstract

Graphene has been considered as a promising material for opto-electronic devices, because of its tunable and wideband optical properties. In this work, we demonstrate electro-refractive phase modulation in graphene at wavelengths from 1530 to 1570 nm. By integrating a gated graphene layer in a silicon-waveguide based Mach-Zehnder interferometer, the key parameters of a phase modulator like change in effective refractive index, insertion loss and absorption change are extracted. These experimentally obtained values are well reproduced by simulations and design guidelines are provided to make graphene devices competitive to contemporary silicon based phase modulators for on-chip applications.