Integral-Based Exponential Time-Differencing Algorithm for the Full-Vectorial FDTD-PML Analysis of PCF With Material-Dispersion

A novel integral-based exponential time- differencing (ETD) algorithm for incorporating the material-dispersion of photonic crystal fibers (PCFs) into the finite-difference time domain is introduced. Compared to the auxiliary differential equation method for the PCFs, the proposed algorithm has the same second-order accuracy, but can lead to a substantial savings in both the memory space and CPU time consumption. To establish a rounded system for the open-region problems, an integral-based ETD implementation of the stretched coordinates perfectly matched layer (PML) is proposed. Compared to the reported PMLs for the analysis of PCFs, the proposed implementation can lead to a significant improvement of the absorbing performance when requiring similar memory space. The proposed algorithm is demonstrated to be a unified approach for arbitrary dispersive materials.