Surrogate-based Sensitivity Analysis of Facet Optical Coatings Produced without and with in-situ Design Re-optimization

Abstract Optoelectronic and photonic waveguide-based devices often require the control of the exit/entrance facet reflectance to a high degree of precision on a relatively large wavelength range. Fabricating facet optical coatings for that purpose can be challenging due to detrimental effects of thickness errors. In this work, a surrogate approach using the polynomial chaos expansion method is used to evaluate the robustness of optical coating designs to experimental errors, and the Sobol' sensitivity indices of their individual layers. The effect of a fabrication strategy involving successive {\it in-situ} design re-optimizations after completion of each individual layer deposition is simulated and shown to reduce significantly the detrimental effect of thickness errors on the yield and performance of coatings.