Oscillations at a difference frequency in the middle and far infrareds in GaP semiconductor waveguides

The feasibility of oscillation at a difference frequency in the middle and far infrareds is considered under the condition of phase matching between a nonlinear polarization wave and a difference mode produced by two fundamental modes with a wavelength near 1 μm excited in a GaP dielectric waveguide. With 10-W short-wave modes propagating in a 100-μm-wide planar waveguide, the power of the difference mode can be as high as 300 μW at 1–8 THz at room temperature. When the GaP waveguide leans upon a silicon substrate, the power of the difference mode may reach 5 mW at 10–14 THz at the same temperatures.