Question

An optical ray makes an angle 1050

at core cladding interface of a step index fiber. Check whether this

ray will be guided by the fiber or not. Given that the refractive indices of core and cladding are 1.455

and 1.445 respectively.​

Answer 1

Answer:

Consider the optical fiber from Sample Problems 1 and 2 . The index of refraction of the inner core is 1.480 , and the index of refraction of the outer cladding is 1.44.

A.

What is the critical angle for the core-cladding interface?

B.

For what range of angles in the core at the entrance of the fiber (2) will the light be completely internally reflected at the core-cladding interface?

C.

What range of incidence angles in air does this correspond to?

D.

If light is totally internally reflected at the upper edge of the fiber, will it necessarily be totally internally reflected at the lower edge of the fiber (assuming edges are parallel)?

1.

As before, we will need to combine Snell's Law with geometrical arguments.