Patent ID: 6801348
Filing Date: 2004-10-05
Classification: G03H,G11B

Abstract:
A method of recording holograms in a waveguide layer structure, the waveguide layer structure containing multiple waveguide layers (3,23), and spacer layers (4,29) separating the waveguide layers (3,23), the index of refraction of the spacer layers being smaller than the index of refraction of the waveguide layers, comprising the steps of recording the holograms in or in the vicinity of each waveguide layer as an interference betweenan object beam (5,45), the object beam being essentially perpendicular to the plane of the waveguide layer structure and a reference beam (11,41) coupled into said each waveguide layer (3,23), wherein a grating (12,42) is associated to each waveguide layer (3,23) for selectively coupling the reference beam (11,41) into said each single waveguide layer (3,23) of the waveguide layer structure, and wherein the gratings (12,42) are having different pitch and/or profile and/or orientation around the axis perpendicular to the plane of the waveguide layer structure in the different waveguide layers, the reference beam (11,41) is projected onto the gratings (12,42) a. in different incidence azimuthal angles and/or b. from different directions around an axis perpendicular to the plane of the waveguide layer structure, whore the components of the different directions falling in the plane of a waveguide layer structure are also different.