[1] Gedeon A. Comparison between rigorous theory and WKB-analysis of modes in graded-index waveguides. Opt. Commun., 1974, 12(4):329~332
[2] Adams M J. An Introduction to Optical Waveguides. New York: Chichester, 1981. Chapter 4, 5
[3] Qiao Li, Wang Jingyi. A refined WKB method for planar waveguides with asymmetric graded-index profile. Opt. Commun., 1991, 83(1, 2):144~153
[4] Wang Jingyi, Qiao Li. A refined WKB method for symmetric waveguides with truncated-index profiles and graded-index profiles. IEEE J. Quant. Electron., 1991, QE-27(4):878~883
[5] Qiao Li, Jingyi Wang. A modified ray-optic method for arbitarary dielectric waveguides. IEEE J. Quant. Electron., 1992, QE-28(12):2721~2727
[6] Feng Xiang, Gar Lam Yip. A modified WKB method for the improved phase shift at a turning point. J. Lightwave Technol., 1994, LT-12(3):443~452
[11] Ikuno H. Analysis of wave propagation in inhomogeneous dielectric slab waveguides. IEEE Trans. Microwave Theory and Tech., 1978, MTT-26(4):261~266
[12] Goyal I C, Gallawa R L, Ghatak A K. Methods of analyzing planar optical waveguides. Opt. Lett., 1991, 16(1):30~32
[13] Mishra K, Sharma A. Analysis of single mode inhomogeneous planar waveguides. J. Lightwave Technol., 1986, LT-4(2):201~204
[14] Korotky S K, Minford W J, Luhl L L et al.. Mode size and method for estimating the propagation constant of single-mode Ti:LiNbO3 strip waveguides. IEEE J. Quant. Electron., 1982, QE-18(10):1796~1801
[15] Adams M J. The claded parabolic index profile waveguide: Analysis and application to strip-geometry lasers. Opt. & Quant. Electron., 1978, 10(1):17~29
[16] Srivastava R, Kao C K, Ramaswamy R V. WKB analysis of planar surface waveguides with truncated index profiles. J. Lightwave Technol., 1987, LT-5(11):1605~1609