LOW-LOSS PLANAR OPTICAL WAVE-GUIDES IN STRONTIUM BARIUM NIOBATE CRYSTALS FORMED BY ION-BEAM IMPLANTATION

Planar optical waveguides have been formed in strontium barium niobate single crystals by either proton or heliumion implantation. The profi les of the ordinary and the extraordinary refractive indices are deduc ed from dark-line mode spectroscopy. Optical barriers with depths to D elta n(e) = 2.6% for protons and Delta n(e) = 5.5% for helium are obta ined. By proton implantation we find a very low intensity loss of 0.4 cm(-1) for ordinarily and a higher value of 2.7 cm(-1) for extraordina rily polarized light at 632.8 nm. For helium-implanted waveguides both values are similar to 4 cm(-1).