We report on the micron-luminescent properties of carbon ion implanted optical channel waveguides in the Nd:MgO:LiNbO(3) laser crystals. The confocal fluorescence images of the waveguide's cross section are presented based on the analysis of the spatial variation of the Nd(3+) fluorescence properties. We have found that the carbon ion implanted waveguides exhibit hybrid fluorescence properties of both hydrogen and oxygen ion implanted waveguides, which clearly denotes a "boundary" effect of light and heavy ions for waveguide formation in lithium niobate crystals.