Bragg reflector based on periodic structures for silicon MOEMS applications

We report an analytical model for calculation of reflection and transmission coefficients of a Bragg reflector with periodic structure using transfer matrix method. Using explicit expressions for these coefficients, the reflectivity of the periodic structures for different pairs of layers and layer thickness was simulated. We investigate the reflectivity of the periodic structures consisting of following pairs of successive layers: SiO2 /Si3N4 (low ratio of refractive indexes); poly-Si/ SiO2 (high ratio), Si/air-gap (high contrast). The theoretical and experimental investigations of a particular periodic structure consisting of SiO2/Au are also presented. Our method allows the rapid evaluation of reflectance of Bragg reflector with periodic structure.