title: Investigation of the spatial distribution of second-order nonlinearity in thermally poled optical fibers.
abstract: The spatial distribution of second-order nonlinearity in thermally poled optical fibers was characterized by second-harmonic microscopy. The second-order nonlinearity was found to be confined to a thin layer close to the anode surface and progressed further into the silica as the poling time increased. Position uncertainty of the anode metal wire was observed to have an effect, as the nonlinear layers were found not always symmetrically located around the nearest points between the anode and cathode. Optical microscopy results were obtained on etched poled fiber cross-sections and compared with those from second-harmonic microscopy.
authors.forename: Honglin
authors.initials: H
authors.lastname: An
authors.forename: Simon
authors.initials: S
authors.lastname: Fleming