Exact and variational Fourier transform methods for analysis of multilayered planar waveguides

Exact and variational Fourier transform methods for the analysis of generalised planar waveguide structures are described in detail. Results are presented for specific structures of technological importance, namely the rib and channel waveguides and the rib waveguide directional coupler. These results establish the accuracy of Fourier transform methods in calculating critical design parameters such as propagation constant, field profile and coupling length. Moreover, they compare very favourably with purely numerical techniques in terms of speed and required computer resources.