An exterior vehicle lighting device, the exterior vehicle lighting device comprising: a light source for generating light, wherein the light source comprises one or more light emitting diodes or solid state light sources; a light panel comprising a plurality of optical fibers arranged in a predetermined form, the light panel emitting light from a surface thereof to meet a desired lighting function; a bundling element for bundling ends of the optical fibers of the light panel together; characterized in that the exterior vehicle lighting device comprises: an optical mixer interposed between the light source and the bundling element and designed to achieve light input coupling, mixing and light output coupling suitable to perform the desired lighting function of the light panel, the optical mixer configured to receive at least a portion of said light from the light source, mix said light and transmit mixed light to the bundling element; and wherein the optical mixer is an integral one piece construction comprising: a light input face configured to input light from the light source, a light output face configured to output light to the input to panel; and a sidewall connecting the light input face to the light output face, wherein the optical mixer is configured to provide output light from the output face having greater spatial uniformity than input light entering the input face. a light source for generating light, wherein the light source comprises one or more light emitting diodes or solid state light sources; a light panel comprising a plurality of optical fibers arranged in a predetermined form, the light panel emitting light from a surface thereof to meet a desired lighting function; a bundling element for bundling ends of the optical fibers of the light panel together; characterized in that the exterior vehicle lighting device comprises: an optical mixer interposed between the light source and the bundling element and designed to achieve light input coupling, mixing and light output coupling suitable to perform the desired lighting function of the light panel, the optical mixer configured to receive at least a portion of said light from the light source, mix said light and transmit mixed light to the bundling element; and wherein the optical mixer is an integral one piece construction comprising: a light input face configured to input light from the light source, a light output face configured to output light to the input to panel; and a sidewall connecting the light input face to the light output face, wherein the optical mixer is configured to provide output light from the output face having greater spatial uniformity than input light entering the input face. an optical mixer interposed between the light source and the bundling element and designed to achieve light input coupling, mixing and light output coupling suitable to perform the desired lighting function of the light panel, the optical mixer configured to receive at least a portion of said light from the light source, mix said light and transmit mixed light to the bundling element; and wherein the optical mixer is an integral one piece construction comprising: a light input face configured to input light from the light source, a light output face configured to output light to the input to panel; and a sidewall connecting the light input face to the light output face, wherein the optical mixer is configured to provide output light from the output face having greater spatial uniformity than input light entering the input face. a light input face configured to input light from the light source, a light output face configured to output light to the input to panel; and a sidewall connecting the light input face to the light output face, wherein the optical mixer is configured to provide output light from the output face having greater spatial uniformity than input light entering the input face.