Manufacturing a graded index profile for waveguide display applications

A waveguide comprising:

• a waveguide body comprising a solid composite resin, the waveguide body further comprising:
• a first surface,
• a second surface parallel to the first surface, and
• a central layer in between the first surface and the second surface, wherein the solid composite resin has a substantially graded refractive index profile with a refractive index varying along a first dimension orthogonal to the first and second surfaces, wherein the refractive index is substantially not varying along second and third dimensions parallel to the first and second surfaces, wherein the first, second, and third dimensions are orthogonal to each other,
• wherein:
• the solid composite resin includes a cured inter-diffused mixture of first and second resins, wherein the cured inter-diffused mixture was obtained by co-flowing the first and second resins in a diffusion channel and curing the co-flown inter-diffused mixture of the first and second resins at a distance from an inlet of the diffusion channel,
• a ratio of the second resin to the first resin in the solid composite resin varies from the central layer to the first surface and the second surface along the first dimension, and
• a first index of refraction of the first resin is different from a second index of refraction of the second resin.