Silicon-germanium electro-absorption modulator

An electro-absorption modulator, comprising:

• a substrate layer, comprising a silicon substrate and an oxide layer disposed on the silicon substrate;
• a top-layer silicon, wherein a waveguide layer is formed on the top-layer silicon;
• a doping layer, formed on the top-layer silicon, wherein the doping layer comprises a first doping panel and a second doping panel, a first-type light doping area is formed on the first doping panel, a second-type light doping area is formed on the second doping panel, the first-type light doping area and the second-type light doping area are located on two sides of the waveguide layer and abut against the waveguide layer, and the first-type light doping area, the waveguide layer, and the second-type light doping area form a PIN junction;
• and
• a modulation layer, disposed on the waveguide layer and connected in parallel to the PIN junction, wherein when a beam with a specific wavelength enters a modulation area formed by the modulation layer and the waveguide layer, a modulating electrical signal is reversely applied to the first-type light doping area and the second-type light doping area, optical power of the beam changes after the beam passes through the modulation area, such that electro-optic modulation is implemented for the beam, wherein a light absorption coefficient of the modulation layer for the beam changes with the modulating electrical signal.