Question

assume that an optical fiber has a core refractive index of 1.5 and a cladding refractive index of 1.45, (a) determine the critical angle at the core-cladding interface (in air) (b) find the acceptance angle if the fiber is submerged in a fluid of n

Answer 1

The critical angle at the core-cladding interface in air is 70.32°. The acceptance angle if the fiber is submerged in a fluid with refractive index 'n' is sin^-1(1.45 / n).

(a) To determine the critical angle at the core-cladding interface in air, we can use the formula for critical angle:

sin critical angle = (core refractive index) / (cladding refractive index)

Plugging in the given values:

sin critical angle = 1.5 / 1.45 = 1.03448

Since the critical angle cannot exceed 90°, we can calculate the angle using the inverse sine:

critical angle = sin^-1(1.03448) = 70.32°

(b) To find the acceptance angle if the fiber is submerged in a fluid of refractive index 'n', we can use the formula:

sin acceptance angle = (cladding refractive index) / (refractive index of the fluid)

Plugging in the given values:

sin acceptance angle = 1.45 / n