An optical waveguide apparatus comprising: an optical waveguide element comprising: a first surface; and a second surface opposite to the first surface, wherein the first surface or the second surface comprises an optical structure (130, 230) configured to diffract an incident light, and wherein the incident light enters the optical waveguide element via the first surface and is transmitted to the second surface; and characterized in that the optical waveguide apparatus further comprising: an optical recycling element disposed on the second surface of the optical waveguide element; wherein a zero-order diffracted light and a reflective diffracted light transmitted in the optical waveguide element are generated by the incident light passing through the optical structure, or the zero-order diffracted light and a refractive diffracted light transmitted in the optical waveguide element are generated by the incident light passing through the optical structure, the incident light is transmitted to the optical recycling element via the optical structure and the second surface, and the optical recycling element is configured to reflect the zero-order diffracted light to form a recycled light, the recycled light enters the optical waveguide element via the second surface and is transmitted to the first surface, and the recycled light is transmitted in the optical waveguide element, wherein the recycled light is a first-order or high-order diffracted light. an optical waveguide element comprising: a first surface; and a second surface opposite to the first surface, wherein the first surface or the second surface comprises an optical structure (130, 230) configured to diffract an incident light, and wherein the incident light enters the optical waveguide element via the first surface and is transmitted to the second surface; and a first surface; and a second surface opposite to the first surface, wherein the first surface or the second surface comprises an optical structure (130, 230) configured to diffract an incident light, and wherein the incident light enters the optical waveguide element via the first surface and is transmitted to the second surface; and characterized in that the optical waveguide apparatus further comprising: an optical recycling element disposed on the second surface of the optical waveguide element; wherein a zero-order diffracted light and a reflective diffracted light transmitted in the optical waveguide element are generated by the incident light passing through the optical structure, or the zero-order diffracted light and a refractive diffracted light transmitted in the optical waveguide element are generated by the incident light passing through the optical structure, the incident light is transmitted to the optical recycling element via the optical structure and the second surface, and the optical recycling element is configured to reflect the zero-order diffracted light to form a recycled light, the recycled light enters the optical waveguide element via the second surface and is transmitted to the first surface, and the recycled light is transmitted in the optical waveguide element, wherein the recycled light is a first-order or high-order diffracted light. an optical recycling element disposed on the second surface of the optical waveguide element; wherein a zero-order diffracted light and a reflective diffracted light transmitted in the optical waveguide element are generated by the incident light passing through the optical structure, or the zero-order diffracted light and a refractive diffracted light transmitted in the optical waveguide element are generated by the incident light passing through the optical structure, the incident light is transmitted to the optical recycling element via the optical structure and the second surface, and the optical recycling element is configured to reflect the zero-order diffracted light to form a recycled light, the recycled light enters the optical waveguide element via the second surface and is transmitted to the first surface, and the recycled light is transmitted in the optical waveguide element, wherein the recycled light is a first-order or high-order diffracted light.