Abstract

One of the key challenges on silica-based planar optical waveguides technology is to overcome waveguide intrinsic birefringence and related polarization-dependent response, affecting transmission performances. Birefringence in Si0₂ waveguides mainly originates from anisotropic and asymmetric distributions of stress, arising both from the deposition process and from the difference in the thermal expansion coefficients of substrate and waveguide layers. Recently, the need of evaluate stress distributions dependence on material and structural parameters, for a more efficient preliminary waveguide design, has been put into evidence [1]. Up to now, only spatially averaged residual stress values in optical waveguides have been experimentally evaluated. Photoelastic transmission tomography has already proven adequate to reconstruct local axial stress distributions in optical fibers [2].

© 2007 IEEE