INVESTIGATION OF 3-D SEMIVECTORIAL FINITE-DIFFERENCE BEAM-PROPAGATIONMETHOD FOR BENT WAVE-GUIDES

A three dimensions of semivectorial finite difference beam propagation method (FD-BPM) in cylindrical coordinates is investigated in order t o analyze the optical wave propagation in the bent waveguides with the strong lateral confinement which will keep low radiation loss. The th ree-dimensional (3-D) semivectorial wave propagation equation is progr ammed in the quick and unconditionally stable procedure by using the a lternating-direction implicit method. This version of FD-BPM could wel l express the polarization characteristics of modal field near the die lectric interfaces and accurately simulate the wave propagation in ben t waveguides even at a very small radius (<100 mu m). Moreover, it is pointed out that the numerical precision of the algorithm is intensive ly affected by the propagation loss of bent waveguides along with the propagation step length of beam propagation method.