Applications of singlemode extraction from finite difference time domain data

A simple technique is described which is capable of providing considerable reductions in the computational demands of the finite difference time domai n (FDTD) algorithm. It is shown that, by forming the inner product of the F DTD time domain data and the transverse field variation of the mode of inte rest, it is possible to avoid modelling long feed structures in many FDTD m odels. The precise computational and memory savings resulting from the meth od depend on the structure of interest, figures of 50% and 15% are achieved for two example structures.