Low Loss Optical Waveguides in Glass Fabricated by Electric Field Assisted Diffusion from Silver Films

摘要

This report describes continuing research in fabricating low loss glass waveguides for an integratged optics ring interferometer to be used for inertial rotation sensing. During this year progress was made in identifying the losses which occur during diffusion of a waveguide into glass. We developed special optical glass in which we were able to diffuse waveguides with losses which are four times smaller than observed in preliminary experiments in microscope slides. From its mode-dependence, we were able to determine that the residual loss is due to roughness of the surface introduced by the silver during the diffusion. We introduced the technique of laser writing of masks for integrated optics and succeeded in writing a ring channel mask 10 cm in diameter and 10 micrometer wide. The combination of this mask and a straight-line mask provide the capability for producing a ring interferometer of dimensions required for inertial rotation sensing. We have also demonstrated that photoacoustic spectroscopy may be a very useful tool for determining the silver depth profiles in a nondestructive fashion. (Author)