[1] [1] Suhara T, Handa Y, Nishihara H et al.. Analysis of optical channel waveguides and directional couplers with graded-index profile. J. Opt. Soc. Am., 1979, 69(9):807～815

[2] [2] Strake E, Bava G P, Montrosset I. Guided modes of Ti:LiNbO3 channel waveguides: A novel quasi-analytical technique in comparison with the scalar finite-element method. J. Light Wave Technol., 1988, 6(6):1126～1134

[3] [3] Bersiner L, Hempelmann U, Strake E. Numerical analysis of passive integrated-optical polarization splitters: Comparison of finite-element method and beam-propagation method results. J. Opt. Soc. Am. (B), 1991, 8(2):422～433

[5] [5] Katstriku F A, Rahman B M A, Thomas K et al.. Finite element analysis of diffused anisotropic optical waveguides. J. Light Wave Technol., 1996, 14(5):780～786

[8] [8] Koshiba M. Optical Waveguide Analysis. New York: McGraw-Hill, 1992