Wavelength conversion of an infrared signal through cascaded second-order nonlinearity in a lithium-niobate channel waveguide

We describe a wavelength conversion experiment (generation of a pulse at the wavelength lambda(p) - Delta X from a Signal at lambda(p) + Delta lambda under the action of a pump at lambda(p)) performed through a cascaded second-order process in a lithium niobate channel waveguide. With a 58-mm-long Ti diffused channel waveguide, lambda(p) = 1.1 mu m (the wavelength of phase matching for the first step of sh generation), Delta lambda of several nanometers and 20 ps pulse duration, wavelength conversion with unit efficiency is obtained with a pump pulse energy of the order of 10(2) pJ. The experimental results are successfully interpreted by making use of modal analysis and solving the appropriate nonlinear equations.