The tremendous progress in the fabrication of highly confining silicon-on-insulator (SOI) waveguides has been very beneficial for four-wave-mixing (FWM)-based wavelength conversion applications. Nevertheless, to establish power-efficient and wideband FWM wavelength conversion, one typically requires long (cm-scale) SOI waveguides with dispersion-engineered cross-sections that do not comply with the fabrication constraints of multiproject- wafer-oriented silicon photonics foundries. In this paper, we numerically examine the opportunities for wideband wavelength conversion through FWM in a foundry-compatible SOI waveguide covered with the highly nonlinear two-dimensional material of graphene. When combining subwatt level pump powers with a short waveguide length of only a few hundreds of microns, perfectly phase-matched conversion with significant efficiencies close to 20 dB can be obtained over a more than 40 THz-wide signal band adjacent to the pump frequency. Because of the tunability of the graphene properties, it is also possible to obtain quasi-phase matched FWM conversion through a periodic sign reversal of the graphene third-order nonlinearity along the waveguide. Conversion efficiencies exceeding 30 dB can be achieved over a 3.4 THz-wide signal band that is situated as much as 58 THz away from the pump frequency. Finally, the graphene tunability also allows for switching between the perfectly phase-matched and quasi-phase-matched operation modes.
|