An optical element capable of emitting light having a light intensity distrubition similar to an incandescent light source, including: a light transmissive light guide having an input end, an output end, and a central region therebetween, the light guide extending along an axial direction; a light unit including at least one light emitting diode, the light unit being arranged adjacent to the input end for injecting light into the central region; and a reflector being arranged adjacent to the output end and arranged such that at least a portion of light incident on a reflecting surface portion of the reflector is reflected; the reflecting surface portion of the reflector is concave and curving inwards into the light guide, wherein: the light guide is arranged such that its index of refraction is higher than the index of refraction of the medium exterior to the light guide characterised in that a portion of a surface of the light guide in close proximity to its input end includes a prismatic surface comprising a plurality of prisms (5a, 5b, 5c) arranged in a succession along the axial direction for guiding the majority of the light emitted from the light unit to the output end of the light guide, the angle of prisms to the axial direction being chosen for total internal reflection of the light incident on the prisms, each prism being arranged at an angle to the axial direction such that the angle to the axial direction of at least one of the prisms is different from the angle to the axial direction of other prisms; and at least a portion of the central region of the light guide separates the prismatic surface and the reflecting surface portion in the axial direction. a light transmissive light guide having an input end, an output end, and a central region therebetween, the light guide extending along an axial direction; a light unit including at least one light emitting diode, the light unit being arranged adjacent to the input end for injecting light into the central region; and a reflector being arranged adjacent to the output end and arranged such that at least a portion of light incident on a reflecting surface portion of the reflector is reflected; the reflecting surface portion of the reflector is concave and curving inwards into the light guide, the light guide is arranged such that its index of refraction is higher than the index of refraction of the medium exterior to the light guide a portion of a surface of the light guide in close proximity to its input end includes a prismatic surface comprising a plurality of prisms (5a, 5b, 5c) arranged in a succession along the axial direction for guiding the majority of the light emitted from the light unit to the output end of the light guide, the angle of prisms to the axial direction being chosen for total internal reflection of the light incident on the prisms, each prism being arranged at an angle to the axial direction such that the angle to the axial direction of at least one of the prisms is different from the angle to the axial direction of other prisms; and at least a portion of the central region of the light guide separates the prismatic surface and the reflecting surface portion in the axial direction.