Graphene Based Optical Phase Modulation

TL;DR

This paper demonstrates a novel method for optical phase modulation using graphene embedded in waveguides, achieving large index changes with low voltage, enabling various optoelectronic device functionalities.

Contribution

It introduces a capacitive charge-based phase modulation technique in graphene waveguides with very low voltage-length product, expanding potential applications.

Findings

Achieved phase modulation with VπLπ ≈ 0.04 V·cm

Showed potential for modulators, filters, switches

Demonstrated phase change in microring resonators

Abstract

In this paper we report phase modulation obtained by inducing a capacitive charge on graphene layers embedded in the core of a waveguide. There is a biasing regime in which graphene absorption is negligible but large index variations can be achieved with a voltage-length product as small as $V_\pi\,L_\pi \simeq 0.04 $\,V\,cm . Examples of phase induced changes are computed for straight waveguides and for microring resonators showing the possibility to implement several optoelectronic functionalities as modulators, tunable filters, and switches.