Spatial chirping of wavevector mismatch in LiNbO/sub 3/ segmented waveguides for engineering of specific second-harmonic generation detuning curves for cascading applications

摘要

A new aspect of second-order nonlinearities, namely the generation of large nonlinear phase shifts from cascading, has prompted a great deal of interest. To date high throughput all optical switching using cascaded second-order nonlinearities has been experimentally demonstrated in temperature-tuned waveguide second-harmonic generation (SHG). The success of these devices is based on the spatial nonuniform wavevector distribution and the unique nonlinear phase shift introduced by the temperature tuning method used for phase matching. With the development of quasi-phase-matching (QPM) techniques it is now possible to achieve the required, flexible, grating-assisted phase matching at almost any wavelength by spatial control of the grating period.