Efficient Type II phase-matching second-harmonic generation in Ba:Yb:Nb:RbTiOPO4/RbTiOPO4 waveguides.

Efficient Type II phase-matching second-harmonic generation of a 1125 nm fundamental beam has been obtained using Ba:Yb:Nb:RbTiOPO(4)/RbTiOPO(4) waveguides grown by liquid phase epitaxy. The refractive indices of the epitaxial layer have been measured at different wavelengths, and the Sellmeier coefficients of the chromatic dispersion curves have been obtained. The phase-matching curve shows that the Ba(2+) doping in RbTiOPO(4) contributes to increase the phase-matching range until 900 nm. The measured effective refractive indices of the propagation modes agree well with the theoretical calculations.