Design of a GaP/Si composite waveguide for CW terahertz wave generation via difference frequency mixing

摘要

We design a GaP/Si composite waveguide to achieve efficient terahertz (THz) wave generation under collinear phase-matched difference frequency mixing (DFM) between near-infrared light sources. This waveguide structure provides a strong mode confinement of both near-infrared sources and THz wave, resulting in an efficient mode overlapping. The numerical results show that the waveguide can produce guided THz wave (5.93 THz) with a power conversion efficiency of 6.6 × 10~(-4) W~(-1). This value is larger than previously obtained with the bulk GaP crystal: 0.5 × 10~(-9) W~(-1) [J. Lightwave Technol. 27, 3057 (2009)]. Our proposed composite waveguide can be achieved by bridging the telecom wavelength and THz frequency region.