Optical Waveguide Theory |
In sections 1.2 and 1.3, the basicconcepts in waveguide theory have been introduced. The Eigen value equation fora waveguide, (equation 1.12), has been derived from the wave equation byimposing suitable boundary conditions. This equation provides constraints forthe number of discrete modes allowed in the guide. In section 1.4, theexcitation of guided modes using the prism-coupling and end-coupling techniqueshas been assessed. Despite the greater practical difficulties associated withthe prism-coupling method, it can provide more information on the modeproperties. For example it can select individual modes and can be used toevaluate the propagation constants of the modes and refractive index of theguiding layer.