Surface roughness of Ti:LiNbO3 etched by Ar∕C3F8 plasma and annealing effect

We describe the reactive ion etching of Ti:LiNbO3 single crystal in gas mixtures containing C3F8 and Ar using neutral loop discharge plasma. The surface roughness of etched Ti:LiNbO3 surface under various gas mixture conditions was analyzed by using atomic force microscopy and scanning electron microscopy. The annealing effect of an etched ridge structure waveguides was also observed.