| Quasi-phase-matching (QPM) is a technique which has long been acknowledged for its ability, in theory, to phase-match nonlinear optical interactions. It is only recently that technology (such as periodic poling) has matured to the point where it is commonly used in the laboratory. Lithium niobate is the most commonly used substrate, and periodically poled lithium niobate is even available commercially.; While it is true that QPM can often have advantages as a traditional phase-matching method, there are also tremendous possibilities to engineer new devices using the added degree of freedom afforded from quasi-phase-matching. Moreover, as it is possible to make waveguides, modulators, and other optical components on lithium niobate, it may be used to integrate many components into a single, high-functioning device. In particular, the ability to make high quality waveguides is of importance because waveguides allow tight confinement of light over long distances, thus substantially decreasing the power necessary to harness a nonlinear effect.; This dissertation is concerned with utilizing and investigating the advantages inherent in quasi-phase-matched interactions. In particular, all optical switching using cascaded χ(2) nonlinearities is investigated theoretically and experimentally. An all-optical switch is constructed which is wavelength selective and has a fast temporal response. Such characteristics may be important for use in next generation optical communication systems as demultiplexers of (time and wavelength division multiplexed) ultra-high bit-rate data-streams.; In addition, generating squeezed light using waveguide quasi-phase-matched devices is also explored. Squeezed light is useful for increasing the sensitivity of precision measurements that are limited by quantum noise. A squeezing configuration exploiting a bi-directional pump is demonstrated. This geometry creates both a squeezed vacuum and a matched local oscillator, which allows more efficient detection of the non-classical light. A theoretical investigation of a novel device for generating amplitude quadrature squeezed light, which takes advantage of the ability to manipulate the poling period, is also introduced. |
