Second-harmonic generation in germanium-on-insulator from visible to telecom wavelengths

The second-order [Formula: see text] process underpins many important nonlinear optical applications in the field of classical and quantum optics. Generally, manifests itself only a non-centrosymmetric dielectric medium via an anharmonic electron oscillation when driven by intense field. Due to inversion symmetry, group-IV semiconductors, such as silicon (Si) germanium (Ge), are traditionally not considered ideal candidates for optics applications. Here, we report experimental observation second-harmonic generation (SHG) Ge-on-insulator (GOI) sample under femtosecond pumping. We especially, measurement SHG signal from GOI telecom S-band pumping at nm.