Hemisphere m-line spectroscopy and its application to birefringent KTiOPO4 planar waveguides

A modified m-line technique, based on the use of a high index hemisphere instead of a coupling prism is presented. It allows fast characterization of the optical properties as a function of the propagation direction inside a planar waveguide. Results of an ion-implanted KTP waveguide are presented and compared to prism measurements. It is shown that this technique enhances the precision of the waveguide parameters determination and allows to study advanced features such as strong mode hybridization.