Propagation of eigenmodes and transfer amplitudes in opticalwaveguide structures

摘要

A method of transfer amplitudes suitable for modeling andnsimulation in integrated optical circuits is presented. The method isnbased on vectorial formulation of electrodynamics: distributions andnpropagation of electromagnetic fields in optical circuits are describednby equivalent surface sources. This approach permits a division ofncomplex optical waveguide structures into sets of primitive blocks andnto separately calculate the transfer amplitude for each block. Thentransfer amplitude of the entire optical system is represented by anconvolution of transfer amplitudes of its primitive blocks. Diffractionnin slab regions is taken into account using known propagation functions.nIt is shown that the concept of a normalized transverse eigenfunction ofnthe diffracted field is very useful in calculations of transfernamplitudes. The crucial role of transverse Bloch modes in propagationnthrough multiwaveguide structures is emphasized. With this method, theneigenvalues and eigenfunctions of an arbitrary waveguide structure cannbe obtained with high accuracy. The general approach is illustrated withnthe transfer amplitude and efficiency calculations for a star couplernand a waveguide grating router