Broadband mid-infrared generation by difference-frequency generation in strongly dispersive Bragg reflection waveguides

We present a novel scheme for generation of broadband mid-infrared (mid-IR) radiation using a quasiphase-matched difference-frequency-generation (DFG) process in a planar high index core symmetric Bragg reflection waveguide (BRW) geometry based oil GaN/Al(1)Ga(1-t)N system. By Suitably tailoring the dispersion properties of the BRW so as to maintain the phase-matching condition over a broad range of pump wavelengths. we show that the pump acceptance bandwidth could be enhanced by nine to tell times for a DFG process. This manifests into I broadband mid-IR difference-frequency idler with greater than 280 nm bandwidth close to 4.35 mu m wavelength Since the design presented here exploits the dispersive features of the BRW; we can shift the broadband characteristics to,in desired region of the mid-IR spectrum within the constraints imposed by transparency and nonlinearity of the Constituent materials. The design also facilitates pumping by standard high-power solid-state laser Sources. (C) 2009 American Institute of Physics [doi:10.1063/1.3247072]