Planar optical waveguides formed in β-BBO by MeV O+ implantation

The planar waveguides have been fabricated in z-cut β-BaB2O4 crystal by 2.8 MeV O+ ion implantation with the doses of 8 × 1014 and 2 × 1015 ions/cm2 at room temperature. The waveguides were characterized by the prism-coupling method. The dark modes are measured before and after the annealing at 300°C for 20 and 40 min in air. The refractive index profile is reconstructed using the reflectivity calculation method. It is found that relatively large positive changes of extraordinary refractive indices happen in the guiding regions, and a slight change increases with the doses, which are different from most of the observed ion-implanted waveguides.