Recursive design of a holographic focusing grating coupler.

A method for designing and recording a holographic optical element that is used as a waveguide focusing grating coupler is presented. It is based on recording the holographic coupler with two predistorted wave fronts, derived from interim holograms, whose readout and recording geometries are different. The corrected holographic coupler has almost aberration-free performance even for couplers with very small f/numbers or with large wavelength shift between recording and readout.