Waveguide structures were fabricated in potassium lithium tantalate niobate crystals by the implantation of high energy C12 ions. The implantation forms an amorphous layer with a lowered index of refraction within the depth of the crystal, which serves as the cladding of the waveguides. Two amorphous layers were fabricated at 18.8 and 25.6 μm below the surface of the crystal by implantation at 30 and 40 MeV, respectively. This formed a submerged slab waveguide sandwiched between the two amorphous layers and two slab waveguides that were formed between the surface of the crystal and each of the amorphous layers. Coupling between those waveguides was observed and investigated, and confinement of the light in the sandwiched waveguide was demonstrated.
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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.