Electric field tuning of second-harmonic generation in a three-dimensional LiNbO3 optical waveguide

Electric-field-tuning characteristics of second-harmonic generation in a three-dimensional Ti in-diffused LiNbO3 optical waveguide are reported. It is experimentally revealed that the phase-matching condition for second-harmonic generation can be achieved with low voltage applied across electrodes. For the present optical waveguide, a 1 °C temperature change is equivalent to about 13 V in phase matching, which agrees well with the calculated value. Rapid tuning or switching of parametric interactions in the LiNbO3 waveguide is expected with a low applied voltage.