LED to Fiber Coupling

      

      The edge emitting LED have Laser like output hence can launch sufficient optical power for the data rates upto 560 Mb/sec over several kilometers. Also LEDs are cost effective and reliable.

. The LED to step index fiber coupling efficiency is given by,

       Where,
             P_in is optical power launched into fiber.
              P_s is total source output power.
              Ԏ_x is directional coupling efficiency in parallel direction.
              Ԏ_y is directional coupling efficiency in perpendicular direction.