Nanophotonic Plasmonic Electro-Optical Modulator Based on Ge2Sb2Te5 on a Chip

In this work, we will propose an electro-optic modulator using a Si/Sio2/Al/GST/Cu plasmonic waveguide. This modulator is based on Ge2Sb2Te5 (GST), one of the most significant and widely used phase change materials. When the phase change material (GST) electrically changes the phase from an amorphous state to a crystalline state, it restricts the transmission of waves inside a plasmonic waveguide. The aluminum layer's plasmonic effect, known as surface plasmon resonance (SPR), will enhance the light-matter interaction and generally improve the moderator's performance. There are three types of waveguide side walls in this study: trapezoidal (D1), rectangular (D2), and triangular (D3) shapes. This study used the finite element method (FEM) in COMSOL Multiphysics at the 500 nm-long nano plasmonic optical modulator. The trapezoidal plasmonic waveguide has the highest extinction ratio of 12.37 dB/μm, followed by the triangular waveguide at 9.56 dB/μm, and the rectangular electro-optical modulator at 8.92 dB/μm.