Diffractive optical waveguide and ar glasses

A diffractive optical waveguide, comprising:

• an optical waveguide substrate, and at least one coupling-in region, at least one relay region, and at least one coupling-out region disposed on the optical waveguide substrate;
• each relay region is arranged between the coupling-in region and the coupling-out region;
• a coupling-in grating, arranged in the coupling-in region, wherein the coupling-in grating is configured to couple lights into the optical waveguide substrate and transmit the lights to the relay region and the coupling-out region;
• the coupling-in grating is a one-dimensional grating or a two-dimensional grating;
• a relay grating, arranged in the relay region, wherein the relay grating is configured to change a transmission path of the lights so that the lights cover the coupling-out region;
• and
• a coupling-out grating, arranged in the coupling-out region, wherein the coupling-out grating is configured to couple lights out from the coupling-out region;
• the relay grating and the coupling-out grating are both two-dimensional gratings;
• the coupling-in region and the coupling-out region are both symmetrical in shape, the relay region is symmetrical or asymmetrical in shape.