A Comparison Of Beam Propagation And Coupled-Mode Methods: Application To Optical Fibre Couplers

The instantaneous power in the local normal modes of an optical fibre coupler with both various three-dimensional paraxial electric field propagation methods and coupled-mode theory have been analysed. Calculations show that large improvements in speed result if a low-order, split-operator, finite-difference propagation algorithm is subsituted for the standard split-step fast Fourier transform technique.