Al_xGa_1-xAs nested waveguide heterostructures for continuously phase-matched terahertz difference frequency generation

We previously demonstrated a nested pair of single mode (pump/THz) waveguides which produced guided far-infrared (1.3 THz) light with a record power-normalized conversion efficiency of 1.3x10(-7) W(-1) by way of continuous phase matched difference frequency generation (DFG) [Opt. Express 16, 13296 (2008)]. Using the same numerical simulation tools we used to design and model this LiNbO(3)-based device, we show that a lattice-matched AlGaAs heterostructure, with its significantly lower absorption losses, can produce guided far-infrared light (3.5 THz) with a power-normalized conversion efficiency of 1.3 x 10(-5) W(-1) - some 100 times larger than achieved with the LiNbO(3) structure.