We report a refinement of a previously reported method' for measuring propagation losses in single-mode optical waveguides. The method as previously described applies to isotropic materials (glass); corrections are necessary when anisotropic materials, such as LiNb03, are used. This report describes the method and indicates two means for estimating the corrections for anisotropic materials.
Paul J. Brannon,
"A New Method For Measuring Waveguide Propagation Losses", Proc. SPIE 0835, Integrated Optical Circuit Engineering V, (10 March 1988); doi: 10.1117/12.942310; https://doi.org/10.1117/12.942310