Theoretical simulation shows that APE:LiNbO<sub>3</sub> ridge waveguide can support a more tightly confined fundamental mode
than that of conventional APE or Ti-indiffused channel waveguides. Successful demonstration of such waveguides on
the surface of LiNbO<sub>3</sub> crystal will have potential impact in the area of nonlinear integrated optics. However, the
fabrication process of ridge structures has appeared to be a challenging task. The ridge structures on the surface of X-cut
LiNbO<sub>3</sub> crystal were fabricated by wet/dry etching process using various recipes and corresponding surface
morphologies have been closely investigated.