A general computer simulation analysis of the coupling efficiency between surface emitting LEDs and optical fibers has been carried out using ray tracing techniques. Coupling efficiencies were evaluated as a function of both the fiber numerical aperture (N.A.) and the ratio of the fiber core diameter dF to the LED emission diameter dE for a spherical lens positioned between the LED and fiber. Coupling efficiencies near the theoretical maximum values were obtained for dF/dE ≤ 5 for 0.20-N.A. fibers and for dF/dE ≤ 2.5 for 0.40-N.A. fibers by optimizing the lens’s index of refraction and the LED-to-lens spacing.
© 1983 Optical Society of America
David L. Shealy and Howard M. Berg, "Simulation of optical coupling from surface emitting LEDs," Appl. Opt. 22, 1722-1730 (1983)