Diffraction optical waveguide and augmented reality display device

The invention provides a diffractive optical waveguide and augmented reality display equipment, the diffractive optical waveguide comprises a waveguide substrate, a coupling-in grating and a coupling-out grating, image light is coupled into the waveguide substrate through the coupling-in grating, is transmitted to the coupling-out grating through total reflection, and then is coupled out through the coupling-out grating to enter human eyes; the refractive index of the waveguide substrate is anisotropic and is in rotational symmetry distribution, so that an expected angle range after image light enters the waveguide substrate is smaller than a reference angle range, the reference angle range is an angle range after the image light enters the waveguide substrate when the refractive index of the waveguide substrate is isotropic, and min (n1) < = n2 < max (n1), n1 is the refractive index value of the refractive index anisotropy of the waveguide substrate, and n2 is the refractive index value of the refractive ind