Abstract
An electro-optical modulator includes a structural substrate, having an insulation layer on top. A waveguide layer is on the insulation layer. A resonant layer is on the insulation layer, having a curving rim near the waveguide layer to form an optical coupling region. A gate dielectric layer and a dielectric layer are disposed on the resonant layer. The dielectric layer has a first opening exposing the resonant layer and a second opening exposing the gate dielectric layer. The second opening is adjacent to the curving rim of the resonant layer. A poly layer is on the exposed region of the resonant layer to serve as an electrode. A polysilicon layer is over the dielectric layer and fills the second opening with contact on the gate dielectric layer. A portion of the polysilicon layer on the dielectric layer servers as an electrode.