In this study, we investigate waveguide fields modulated by voltage-induced conductivity changes
in a layer with 'p-i-n' diode-like properties. By applying voltage, we modulate the layer's conductivity
from perfect conductor to free-space conditions, affecting the waveguide's boundary conditions and inducing diffraction and modulation of incident waves. We employ an upgraded evolutionary approach to electromagnetics (EAE), incorporating a novel format of Maxwell's equations, to address this complex interaction. This approach offers new insights into wave modulation phenomena and demonstrates the utility of the EAE in exploring dynamic electromagnetic environments.