<title>Erasure of poling-induced second-order optical nonlinearities in silica by UV exposure</title>

Abstract

Results are presented on the induction of large second order optical nonlinearities in high purity silica glasses by poling or a combination of poling and UV laser exposure for localization of the induced second order effects. Localization is required to achieve quasi phase matching in optical planar waveguides since the induced birefringence in these structures is too small to allow standard phase matching approaches to be used. Samples of Suprasil, Infrasil, and Homosil were poled using standard high temperature poling at 300 degree(s)C with an applied field of approximately 13 kV/cm. Correlation between the poling and depoling currents for these samples and the observed second harmonic generation is seen. The results support the thesis that the origin of the second order nonlinearity is the combination of a large surface field and the intrinsic third order nonlinearity in the glass. Relatively short room temperature UV (257 nm) laser exposure with beam power of a few W/cm2 was found to completely remove the induced second order nonlinearity in thermally poled glasses. This allows a simple fabrication technique for nonlinear or combined linear/nonlinear gratings in planar glass waveguides using thermal poling followed by localization by UV exposure.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.