NUMERICAL VALIDATIONS OF A NONLINEAR PML SCHEME FOR ABSORPTION OF NONLINEAR ELECTROMAGNETIC-WAVES

There have been several algorithms which extend the finite-difference time-domain (FDTD) solution of Max-well's equations to nonlinear elect romagnetic problems. Relative to other methods, FDTD achieves robustne ss by directly solving for the fundamental quantities, electric field E, and magnetic field H in space and time, rather than performing asym ptotic analyses or assuming paraxial propagation and nonphysical envel ope functions. As a result, the FDTD method is almost completely gener al and can account for any type of electromagnetic problems. As in lin ear cases, for a practical simulation, nonlinear FDTD modeling also re quires the development of absorbing boundary conditions (ABC's) to eff ectively absorb the nonlinear electromagnetic waves for open nonlinear structures. In this paper, based on the Berenger's perfectly matched layer (PML), a nonlinear PML (nPML) absorbing scheme is presented and then implemented in the transmission-line matrix (TLM)-based FDTD meth od. Numerical results are given to demonstrate the effectiveness of th e nPML proposed.