Tunable Terahertz Wavelength Conversion Based on Optofluidic Infiltrated Rib Silicon Waveguides

Abstract

Terahertz (THz) sources for various applications have attracted especial attention. Compared with the standard silica-based optical fibers, silicon waveguides have advantages such as higher refractive index and lower absorption loss over the THz region. In this paper, for the first time, a rib silicon waveguide based on the photonic crystal (PC) idea is designed and by using the scalar modulation instability (SMI) phenomenon, tunable wavelength conversion for generation of THz radiation is simulated. By changing the structural parameters such as the air-hole diameter of the PC and infiltration of optical fluids into the air holes, linear and nonlinear characteristics of the waveguide are controlled and hence the generated THz radiation is considered as a tunable source. Simulation presents the maximum converted wavelength of 326.17µm is obtained when the air-hole diameter is set at d=0.86μm, where pump wavelength is in the normal dispersion regime. Also, we have infiltrated optical fluids into PC air holes in order to change the dispersion properties of the waveguide while keeping the geometrical parameters unchanged. This led to converted wavelengths of 70.5, 76.8 and 107.5 μm, all located in the terahertz region. The loss of this waveguide is less than 0.8 � , which is less than that of previously reported in similar silicon waveguides.

Terahertz link with orthogonal polarization over silicon dielectric waveguide

“…This phenomenon is in contrast with metallic waveguides, which tend to experience more loss at higher frequencies because of the skin effect of metal [14]. Si waveguides have also enabled fundamental applications for the generation of THz waves through wavelength conversion [15,16]. However, the limitations of state-of-the-art equipment limit the highest achievable transmission data rates in the THz region.…”