Optical Fiber Communications 4th Edition by Gerd Keiser

Exercise 7

An LED with a circular emitting area of radius 20 m has a lambertian emission pattern with a 100-W/(cm 2 sr) axial radiance at a 100-mA drive current. How much optical power can be coupled into a step-index fiber having a 100- m core diameter and NA = 0.22 How much optical power can be coupled from this source into a 50-mm core-diameter graded- index fiber having = 2.0, n 1 = 1.48, and = 0.01