Optical designers need to build solutions that meet performance specifications and can be manufactured with as little wastage as possible. Traditionally optical design via computer optimization uses a numerical merit function to represent the optical performance of the simulated system. The conventional design approach is to maximize the nominal performance of the design, and then as a separate step, add fabrication tolerances to the nominal parameters so that upon manufacturing the resulting system still performs to specification. This usually results in designs that are very sensitive to manufacturing and alignment errors, which means the optical product is difficult to repeatedly manufacture successfully.
