High-Accuracy Waveguide Leaky-Mode Analysis Using a Multidomain Pseudospectral Frequency-Domain Method Incorporated With Stretched Coordinate PML

A recently developed pseudospectral frequency-domain (PSFD) method employing a penalty scheme is further incorporated with stretched coordinate perfectly matched layers (PMLs) in order to solve waveguide leaky modes. Several standard leaky-mode slab and circular waveguides, including the W-type and M-type ones, are examined first by solving their complex effective indexes and field profiles, showing that the PSFD method achieves computational accuracy on the order of 10^-15. Then, this high-accuracy solver is used to analyze waveguide structures with more complicated geometries, such as the leaky six-air-hole fiber, for which self convergence of accuracy in calculated effective indexes is demonstrated to be on the orders of 10^-14 , and two rectilineal waveguides with sharp corners, i.e., the rib waveguide and the photonic wire. Comparison of the PSFD method obtained results for these more complicated waveguide structures with those from other methods in the literature is presented and discussed.