4.1 Introduction4.2 Formation of Planar Single-Mode Waveguide Problems4.2.1 TE/TM Wave Equation4.3 Approximate Analytical Methods of Solution4.3.1 Asymmetrical Waveguides4.3.2 Symmetrical Waveguides4.3.3 Concluding Remarks4.4 Design and Simulations of Planar Optical Waveguides: Experiments4.4.1 Introduction4.4.2 Theoretical Background4.4.3 Simulation of Optical Fields and Propagation in Slab Optical Waveguide Structures4.5 Appendix A: Exact Analysis of Clad Linear Optical Waveguides4.5.1 Asymmetrical Clad Linear Profile4.5.2 Symmetrical Waveguide4.6 Appendix B: WKB Method, Turning Points, and Connection Formulae4.6.1 Introduction4.6.2 Derivation of the WKB Approximate Solutions4.6.3 Turning Point Corrections4.6.4 Correction Formulae4.6.5 Application of Correction Formulae4.7 Problems4.7.1 Problem 14.7.2 Problem 24.7.3 Problem 34.7.4 Problem 4References