A slab waveguide was fabricated in a potassium lithium tantalate niobate crystal by the implantation of He2+ ions at 2.26 MeV. The waveguide profile and loss were evaluated by measuring the dark mode TE spectrum using the prism coupling method at λ=1.3 μm. The implantation generated amorphous cladding layer 5 μm below the surface of the crystal with a refractive index lower by 3.9% then that of the substrate. The propagation loss of the waveguided modes was found to be 0.1-0.2 dBcm. Thermal stability of the waveguide was obtained by isothermal annealing at 351 and 446 °C. Following the annealing the waveguide index profile remained unchanged when subjected to annealing at 150 °C for one week.
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This research was supported in part by Grant No. 2002341 from the United States-Israel Binational Science Foundation (BSF), Jerusalem, Israel.