title: Calculation of radiation modes by the Lanczos-Fourier expansion.
abstract: For construction of the TE radiation modes of planar waveguides several methods are employed that are based on collocation techniques. The field representation in the core is based on the Lanczos-Fourier sinusoidal series. The numerical codes are very simple and give accurate results. The validity of these methods is checked for constant refractive-index profiles, while numerical results are also given for parabolic profiles. Furthermore, the validity of the orthogonality condition between the guided and the radiation modes is checked. These methods are demonstrated to be effective and can also be employed to study the TM case and waveguides of lossy media, as well as anisotropic and chiral structures.
authors.affiliation: University of Athens, Department of Physics, Applied Physics Division, Electronics Laboratory, Building V Panepistimiopolis, Zografou, 157 84 Athens, Greece.
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Dasyras
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Tigelis
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Tsigopoulos
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Manenkov