a nd:clngg waveguide structure operated at wavelengths of both 632.8 nm and 1539 nm was demonstrated for the first time to our knowledge, which was produced by the 480-kev h+ ion implantation with a dose of 1.0 x 10(17) protons/cm(2). its propagating modes at 632.8 nm and 1539 nm were measured by the well-known prism coupling technique. the refractive index profile at either 632.8-nm wavelength or 1539-nm wavelength was optical barrier type in the proton-implanted nd:clngg crystal optical waveguide, which was calculated by using the reflectivity calculation method. the near-field light intensity distributions were also simulated by the finite-difference beam propagation method in the visible and near-infrared bands.