Nonlinear wave propagation was investigated experimentally in coupled waveguides by means of the cascaded nonlinearity in quasi-phase-matched second-harmonic generation. With a specially designed wave-vector-mismatch distribution along the propagation axis, cascading was optimized for low fundamental depletion. High-contrast, ultrafast all-optical switching with switching powers of tens of watts was observed.
© 1999 Optical Society of America
(130.3730) Integrated optics : Lithium niobate
(130.4310) Integrated optics : Nonlinear
(190.0190) Nonlinear optics : Nonlinear optics
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
R. Schiek, L. Friedrich, H. Fang, G. I. Stegeman, K. R. Parameswaran, M.-H. Chou, and M. M. Fejer, "Nonlinear directional coupler in periodically poled lithium niobate," Opt. Lett. 24, 1617-1619 (1999)