Graphene-Based Optical Phase Modulation of Waveguide TE Modes

In this paper we report TE mode 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 voltagelength product as small as Vp Lp ' 0:07Vcm for straight waveguides and Vp Lp ' 0:0024Vcm for 12 m m radius microring resonators. 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.