THz-wave generation via difference frequency mixing in strained silicon based waveguide utilizing its second order susceptibility χ⁽²⁾

Terahertz (THz) wave generation via difference frequency mixing (DFM) process in strain silicon membrane waveguides by introducing the straining layer is theoretically investigated. The Si₃N₄ straining layer induces anisotropic compressive strain in the silicon core and results in the appearance of the bulk second order nonlinear susceptibility χ⁽²⁾ by breaking the crystal symmetry. We have proposed waveguide structures for THz wave generation under the DFM process by.using the modal birefringence in the waveguide core. Our simulations show that an output power of up to 0.95 mW can be achieved at 9.09 THz. The strained silicon optical device may open a widow in the field of the silicon-based active THz photonic device applications