A light emitting panel backlighted by an optical fiber assembly is provided in which the individual optical fibers are positioned in parallel across the bottom of a frame and transverse notches are scored in the cladding so as to permit lateral emission of light along the length of the fibers. The lateral emissions impinge on an emitter and are projected onto a diffusing plate mounted in the top of the frame to provide uniform illumination throughout the entire area of the light emitting panel. Increased light throughput is obtained by inducing air flow at the end of the optical fiber bundle to keep the end surface cool by removing the heat from light energy impinging upon the end.