US Patent 10048647 Optical waveguide including spatially-varying volume hologram

An optical waveguide includes a waveguide body and a spatially-varying volume hologram. The volume hologram increases, in a coordinate direction along the volume hologram, an angle of incidence by which light propagating in the waveguide body via total internal reflection is released from the waveguide body. The optical waveguide may form part of an optical system that includes one or more light sources and/or optical sensors.