All-Optical Ultrawideband Monocycle Generation Using Quadratic Nonlinear Interaction Seeded by Dark Pulses

We propose and demonstrate a new approach to all-optical generation of ultrawideband (UWB) monocycle pulses using the quadratic nonlinear interaction seeded by dark pulses in a periodically poled lithium niobate (PPLN) waveguide. When feeding two dark optical pulses with proper relative time delay to participate in the sum-frequency generation (SFG) in a PPLN, the parametric depletion effect accomplishes the tailoring of the dark pulse to be a UWB monocycle pulse at a single wavelength. Pairs of polarity-inverted UWB monocycle pulses are generated in the experiment with the central wavelength, 10-dB bandwidth, and fractional bandwidth conforming to the UWB definition by the U.S. Federal Communications Commission (FCC, part 15).