LaAlO<sub>3</sub> crystals were implanted by C ions and O ions at an energy of 6.0 MeV with a fluence of 1.5×10<sup>15</sup> ions/cm<sup>2</sup>. The profiles of the guided modes were measured through prism coupling and end-face coupling methods with a 633 nm laser source. A nonleaky waveguide structure in the TM mode was fabricated by O ion implantation after a proper annealing treatment. Characteristics of the implanted C and O ions were compared. Some changes of the full width at half of the maximum and intensity of the Raman spectra were observed between the waveguide and substrate regions in LaAlO<sub>3</sub> crystals. Thus, the Raman spectra can be used to visualize any damage or defects in the LaAlO<sub>3</sub> crystals during the implantation process.