Ultracompact Electro-Optical Modulator-Based Ge2Sb2Te5 on Silicon

We propose an electrically driven electrooptical modulator integrated with the phase-change material Ge2Sb2Te5 (GST). This modulator incorporates a hybrid Si-GST-Cu waveguide with input and output Si waveguides. For the waveguide modulator with an active segment of 0.2 mu m(2), the switched phase is stable with off/on extinction ratios of >5.4 dB on the entire C-band. Since the phase change of GST only consumes energy during the stated transitions, the energy consumption per bit for this nanosize device is ideally low on the order of sub-nJ per cycle.