An FD/FDTD method for optical waveguide modeling

As the complexity of optical devices increases, the need for accurate characterization of mode propagation in these structures is of paramount importance. We propose a simple finite difference (FD) method in which Maxwell´s time-harmonic equations are discretized directly on a standard finite-difference time-domain (FDTD) grid to obtain an eigenvalue equation. Direct or iterative solutions can then be used to obtain the modal characteristics. The resulting modal field distributions are subsequently incorporated into FDTD simulations to allow evaluation of reflection and transmission characteristics for arbitrary optical structures.