The figure at the right shows light entering the core of an optical fiber at an angle. The core has an index of refraction n₁ = 1.65 and the cladding has an index of refraction n₂ = 1.60. The optical fiber is in the air. Recall that optical fiber operate based on total internal reflection at the core–cladding interface (point “A” in the figure). Calculate the range of angles, ?, for which total internal reflection will occur at point A.

 

n2 A 1