Ion beam energy attenuation for fabrication of buried, variable-depth, optical waveguides

Buried waveguides with graded depths have been fabricated using a focussed ion beam, direct-write process in fused silica by irradiation with 3 MeV protons through a tapered film varying in thickness from 5 to 40 mu m. The resulting waveguides ramp uniformly from 25 to 80 mu m below the substrate surface. The waveguides are also uniform in cross section along their lengths. This demonstrates the potential for this fabrication technique to direct-write three-dimensional waveguide devices within a substrate. (C) 2000 Elsevier Science B.V. All rights reserved.