Application of the finite-difference beam-propagation method to optical waveguide analysis

The finite-difference beam-propagation method (BPM) is applied to the eigenmode, propagating beam and time-domain analyses of optical waveguides. First, the eigenmode of a bent waveguide is calculated with the aid of the imaginary-distance procedure. Second, the wavelength demultiplexer based on the multimode interference coupler is investigated through the propagating beam analysis. Finally, a waveguide grating is analyzed using the time-domain BPM. The spectral response of reflected waves is revealed and discussed.