THE SEMIVECTORIAL BEAM PROPAGATION METHOD

We present details of an efficient semivectorial beam propagation meth od. In this method, the propagation is performed by solving the finite -difference equation in alternating directions. Different from traditi onal split-operator beam propagation method, the index term is not sep arated from spatial differentiations. Since boundary conditions at die lectric interfaces can be satisfied by two orthogonal polarizations in dividually, the method is semivectorial. The performance can be enhanc ed by using a nonuniform grid. By modifying the routine, it can also b e applied to periodic structures. Numerical results of rib waveguides are presented.