An optoelectronic converter using graphene coating approach

In this paper, we propose an ultra-fast and adjustable optoelectronic converter over a wide wavelength range. The proposed structure includes a triplexer and an optical encoder. In this design, graphene nanoshells are coated on silicon photonic crystal rods in a ring resonator configuration. Adjustment of the triplexer is achieved by changing the chemical potential of the graphene nanoshells by applying an electrical voltage. This tuned triplexer extracts three quantized discrete levels from the continuous input signal, whereas the optical encoder provides 2-bit binary codes. According to plane wave expansion and finite difference time domain methods, the proposed device's maximum response time is about 2.2 ps, with a sampling rate of 454 GS/s while its footprint is as small as 818 mu m(2).