Optical Waveguide in Gd0.275Y0.725Ca4O（BO3）3 Crystals Formed by MeV He Ion Implantation

A GdxY1-x Ca4O(BO3)3 (Gdx Y1-X COB) crystal, which belongs to rare-earth calcium oxyborate family, is used for non-critical phase-matching of visible and ultraviolet (UV) light. We employ 2.8-MeV He+ ions to form optical waveguides in the Gd0.275 Y0.725 COB crystal at room temperature. The doses are varied from 1.5×10^16 ions/cm^2 to 5×10^16 ions/cm^2. A model 2010 prism coupler is used to measure the modes in Gd0.275 Y0.725 COB waveguides formed by MeV He^+ ion implantation. The refractive index profile is fitted based on the reflectivity calculation method. The shape of refractive index profile is compared with one of nuclear energy loss obtained by TRIM'98 simulation.