Cut-off character and single-mode condition for planar waveguides of anisotropic crystal

Based on fundamental theories of waveguides, the guided mode theory of anisotropic crystal waveguide is developed to give the Field distribution Formulas and optical dispersion equations of TE and TM modes of step-like refractive index distribution waveguide, and discussion of their cut-off character and single mode condition is made as well. On the basis of the above-mentioned results, the mode theory of planar waveguide with graded refractive index distribution is analysed for the first time, and the general expressions of dispersion formula are obtained, Rb:KTP waveguide is fabricated by ion-exchange method and its cut-off character and diffusion feature are discussed. At last, the single mode condition For KTP waveguide is deduced.