The index of refraction of the core of a typical fiber optic is n_{core} core  = 1.51; the cladding has n_{clad} clad  = 1.43. calculate the critical angles for the total internal reflection i_{crit}i crit  and α_{crit}α crit .

Given:

refractive index of core,

refractive index of clad,

Explanation:

Critical angle can be defined as the incidence angle which results in the refraction angle being equal to at that angle of incidence.

For Total Internal Reflection to occur, the incidence angle must be greater than the critical angle.

Now, we know that the critical angle, is given by:

Now, for :