Periodically poled ridge waveguide on X-cut LiNbO3 and its application for second harmonic generation

To enhance the efficiency of nonlinear interactions, ridge waveguides can be developed leading to a strong enhancement of the guided mode intensity. If fabricated in a ferroelectric, highly nonlinear material like Lithium Niobate (LN), a periodic domain inversion is required to enable quasi phase matching (QPM) for second order nonlinear processes. Several methods have been used to get periodically poled (PP) ridge structures; they all use a PP substrate for waveguide fabrication [1–3]. In contrast, we report here periodic poling localized in the body of Ti in-diffused ridge waveguides (Ti:PPLN) on X-cut LN and demonstrate the high waveguide quality by efficient second harmonic generation (SHG).