Sol-Gel Synthesis of thin Films for use as Planar Waveguides

Abstract

SiO2-TiO2 sol-gel solutions and synthesis techniques have been developed to produce thin films of proper index, thickness and quality for use as planar waveguides. The composition of the synthesized films ranged from 50 to 68 mole % TiO2 and produced layers with indices ranging from 1.7 to 1.8. Final film thicknesses ranged from 1000 to 3000 A and varied as a function of the coating chemistry and conditions. Also, changes in film shrinkage and index with heat treatment were determined and compared to literature data on similar films used as antireflective coatings. Finally, confirmation of the waveguiding qualities of these films was made through prism coupler measurements conducted by the University of Arizona Optical Sciences Center.