Step-index optical waveguide produced by multistep ion implantation in LiNbO3

The refractive indexes, material attenuation and damage fractions
of a multi-step ion implanted Lithium Niobate (LiNbO3) waveguide were
analyzed as functions of the annealing temperatures. An almost flat damage
depth profile was designed to reduce the uncertainties related to the indexes
profile shape, thus providing a better test-case for the characterizations. The
measurements performed on the fabricated optical waveguides confirmed
the predicted step-index profiles showing that the light is confined inside
the damaged layer. The low measured attenuation (less than 0.8 dB/cm @
632.8 nm) makes the obtained waveguide attractive for device fabrication.