Answer to Question #149499 in Optics for Selena

Question

A silica optical fibre has a core refractive index of 1.50 and a cladding refractive index of 1.45. Determine the critical angle at the core cladding interface. *

Answer 1

Core refractive index $n_1 = 1.50$

Cladding refractive index $n_2 = 1.45$

Snell’s Law:

$sinθ_c = \frac{n_2}{n_1}$

$θ_c$ is the critical angle

Critical angle at the core cladding interface:

$θ_c = sin^{-1}(\frac{n_2}{n_1}) \\ = sin^{-1}(\frac{1.45}{1.50}) \\ = 75.16 º$

Answer: 75.16 º