Minimal perturbation approach implementation in spectral methods

Pseudospectra and minimal perturbation approach (MPA) principles are used and implemented to provide more stability and more rigorous mathematical foundations for the functional expansion multi-domain spectral method (MDSM). The implemented formulation is used to analyze optical waveguides and semiconductor quantum wells. The results show that MDSM formulation based on the MPA is very stable and slightly more accurate as compared to the Tau MDSM.