We examine the influence of the refractive index core profile on the modal scattering of abruptly terminated slab waveguides. The analysis is based on the integral equation method with accelerating parameters, while for the field description in the waveguide core, an appropriate Lanczos–Fourier expansion is employed. The electric-field distribution on the terminal plane, the reflection and transformation coefficient of the TE guided modes, and the far-field radiation pattern are computed. Numerical results are presented for slab waveguides with step, linear, and parabolic refractive index profiles of the core. Finally, several approximate analytical solutions are derived to study the problem in question and to explain the results obtained.
© 2007 Optical Society of America
Original Manuscript: September 13, 2006
Revised Manuscript: December 13, 2006
Manuscript Accepted: December 18, 2006
Published: May 9, 2007
Panagiota A. Koukoutsaki, Nikolaos F. Dasyras, Ioannis G. Tigelis, Alexander B. Manenkov, and Angelos J. Amditis, "Influence of the refractive index core profile on modal scattering of terminated two-dimensional waveguides," J. Opt. Soc. Am. A 24, 1752-1760 (2007)