Modelling of two-dimensional grating couplers on silicon-on-insulator waveguides using beam propagation method

We show how the parameters of a 3-D laser beam can be taken into account in the calculation of the coupling efficiency into a waveguide via a diffract ion grating. Two well known formalisms are used: (i) differential analysis of the stratified guiding structure supporting the grating, and (ii) beam p ropagation method used to model the propagation in the waveguide, Both are linked by the Helmholtz equation in which a source term has been added corr esponding to the field diffracted by the grating. Some results are given. ( C) 2001 Elsevier Science B.V. All rights reserved.