Optical Planar Waveguides in KTiOPO₄ Crystals by MeV Oxygen Ion Implantation

We report on the optical planar waveguide formation in KTiOPO₄ crystals by single or double oxygen ion implantation at energies of 2.4--3.0MeV and doses of 10¹⁵ions/cm². The dark-line spectroscopy properties are investigated by a prism-coupling method. With an effective refractive index method, the refractive index profiles of the waveguides are reconstructed. The program code TRIM’98 (transport of ions in matter) is used to simulate the implantation process of oxygen ions into the KTiOPO₄ crystal. It is found that an inherent relationship exists between the nuclear damage and the refractive index changes induced by the ion-beam implantation.