Multiplexed volume hologram couplers for augmented reality waveguides

A waveguide assembly, comprising:

• a waveguide that propagates light at angles of incidence greater than a critical angle at which total internal reflection occurs;
• an input coupler comprising at least two gratings within a first three-dimensional (3D) volume, each grating within the first 3D volume being responsive to input light of different wavelengths to reflect or transmit the input light into the waveguide as propagating light, each grating within the first 3D volume having at least one of a (1) same periodicity but a different orientation or (2) a same orientation but a different periodicity, to provide a different refractive index relative to each other grating within the first 3D volume;
• and
• an output coupler comprising at least two gratings within a second 3D volume, each grating within the second 3D volume being responsive to propagating light of different wavelengths propagating in the waveguide within an angle of incidence of the output coupler at which the propagating light is reflected or transmitted out of the waveguide, each grating within the second 3D volume having at least one of a (1) same periodicity but a different orientation or (2) a same orientation but a different periodicity, to provide a different refractive index relative to each other grating within the second 3D volume.

An eyewear device, comprising:

• an image source;
• a display comprising an eye box;
• a waveguide that propagates light at angles of incidence greater than a critical angle at which total internal reflection occurs;
• an input coupler comprising at least two gratings within a first three-dimensional (3D) volume, each grating with the first 3D volume responsive to input light of different wavelengths from the image source to reflect or transmit the input light into the waveguide as propagating light, each grating within the first 3D volume having at least one of a (1) same periodicity but a different orientation or (2) a same orientation but a different periodicity, to provide a different refractive index relative to each other grating within the first 3D volume;
• and
• an output coupler comprising at least two gratings within a second 3D volume, each grating within the second 3D volume responsive to propagating light of different wavelengths propagating in the waveguide within an angle of incidence of the output coupler at which propagating light is reflected or transmitted out of the waveguide to the eye box of the display, each grating within the second 3D volume having at least one of a (1) same periodicity but a different orientation or (2) a same orientation but a different periodicity, to provide a different refractive index relative to each other grating within the second 3D volume.