Modeling of phase volume diffractive gratings, part 2: reflecting sinusoidal uniform gratings, Bragg mirrors

A detailed model of diffraction of plane and Gaussian beams on plane uniform phase Bragg gratings based on a Kogelnik's theory of coupled waves is presented. The model describes reflecting gratings (Bragg mirrors) with arbitrary orientation in a plane-parallel plate having no material losses. It takes into account spectral width and angular divergence of laser beams. The results of modeling are compared with experimental data for Bragg mirrors in a photo-thermo-refractive glass. 1 Introduction A detailed model of diffraction of plane and Gaussian beams on plane uniform phase Bragg gratings based on a Kogelnik's theory of coupled waves is presented. The model describes reflecting gratings (Bragg mirrors) with arbitrary orientation in a plane-parallel plate having no material losses. It takes into account spectral width and angular divergence of laser beams. The results of modeling are compared with experimental data for Bragg mirrors in a photo-thermo-refractive (PTR) glass. Wide applications of volume Bragg gratings (VBG) in optics and photonics require comprehensive practical knowledge of such optical elements. In spite of Kogelnik's theory of coupled waves 1 developed about 40 years ago, no reduction to practical formulae enabling precise design of VBGs has been provided up to today. VBGs in the case of a mono-chromatic plane wave were also treated in detail in Ref. 2, which considers Fresnel reflections and the added effects of composite VBGs such as using two VBGs to form a Fabry-Perot cavity, but also does not address a reduction to practical formulae for designers. A detailed modeling of the diffraction of plane monochro-matic waves along with divergent and polychromatic beams