Transverse electric/magnetic switchable absorption ring modulator based on graphene

We propose a transverse electric (TE)/transverse magnetic (TM) switchable absorption ring modulator based on graphene that can operate in either the TE or the TM mode. By adjusting the applied voltages onto the graphene layers in horizontal and perpendicular directions, either a TE or a TM absorption ring modulator can be configured, as has been previously reported. The simulation results show that a TE or TM modulator can be configured with a large extinction ratio and wide waveband from 1300 to 2000 nm. Specifically, the modulation bandwidth can be enlarged to over 130 GHz, which is rarely seen in conventional ring modulators. Also investigated is the possibility of extending the resonance wavelength shift to more than 5 nm by replacing the monolayer graphene structure with a quadrilayer graphene structure.