Calculation of bending losses in dielectric waveguides using eigenmode expansion and perfectly matched layers

In this letter, we present a different approach to accurately calculate the bending losses in curved dielectric waveguides. It is based on the well-known conformal transformation of the index profile and on vectorial eigenmode expansion, but this time with perfectly matched layer (PML) boundary conditions to accurately model radiation losses. The modal spectrum of these waveguides in the presence of PML is discussed and the method is validated by comparing it to previously published results.