Propagation behaviour of cylindrical-dielectric-rod waveguides

The exact propagation behaviour is considered of cylindrical dielectric waveguides possessing a central core of higher permittivity than the surrounding cladding. Results are compared with those obtained by making the coremode and cladding-mode approximations. The former approximation is found to be valid for most purposes; the latter is much more restricted. Although the waveguide parameters chosen are representative of monomode optical waveguides, the results should find wider application.