High-uniformity dielectric U-shaped surface relief grating coupler for AR headsets

In this work we propose a new type of symmetrical surface relief diffractive grating for waveguide-based Augmented Reality (AR) near-eye display system with a wide field of view (FOV). We demonstrate that by using a dual mode symmetrical in-coupling system and pupil angular tiling, we can extend the overall horizontal FOV. Our grating coupler is optimized for the second diffraction orders. The proposed concept is validated numerically via full-wave electromagnetic analysis of a 1D diffraction grating. Measurement of diffraction efficiency of the micro-fabricated prototype has demonstrated good agreement with the results of numerical simulations for the design wavelength.