Dispersion of the ordinary refractive-index change in a proton-exchange LiNbO3 waveguide.

The wavelength dependence of the ordinary refractive-index change of a proton exchanged LiNbO3 waveguide is determined by applying a recently proposed method based on radiation modes. A peculiar behavior is observed since the absolute value of the ordinary index change increases with the wavelength, while the extraordinary one decreases. The Sellmeier curves for the dispersion of both the index changes are provided in the wavelength range from 0.514 micron to 1.554 micron.