Free Carrier Plasma GeSn Modulator for Mid-Infrared Integrated Microwave Photonics

A high-speed Si-based Free Carrier Plasma (FCP) GeSn Germanium-Tin (GeSn) modulator is designed and simulated for infrared integrated microwave photonic applications. The design is based on the capabilities to grow GeSn on Si using CVD method. The structure is composed of a laterally doped p-i-n Ge0.95Sn0.05 rib waveguide for modulation at 2 μm. The refractive index changes as a result of applied voltage is observed in the device. The transient effective refractive index change analysis shows up to 1 GHz modulation speed at 2 μm with the proposed structure. This results show that FCP GeSn is a promising design for fabrication of high-speed infrared microwave photonics modulators.