Ultracompact Electro-Optical Modulator-Based Ge₂Sb₂Te₅ on Silicon

Abstract

We propose an electrically driven electro-optical modulator integrated with the phase-change material Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> (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 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , 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.