Error Analysis procedure of OptiLayer provides a statistical evaluation of the effect that errors in the layer thicknesses and refractive indices in a design will have on the spectral response of a designated spectral characteristic.

As the computations proceed, a sequence of curves corresponding to the number of statistical tests is plotted on the screen. During the computations, the progress of the statistical procedure is indicated by the percentage bar at the bottom of the window. At the end of the computational procedure, the original (theoretical) spectral characteristic is plotted. It is accompanied by the mathematical expectation (denoted as Exp in the window legend) and two curves indicating the probability corridor for a given error level (these curves are denoted as Exp+-D in the legend).