Numerical Aperture slides for optical fiber

1. The Basics of Fiber
Optics
Numerical Aperture & related
mathematical problems
Dr. Iqbal Ahmed
Associate Professor
Dept. of Computer Sci. & Engg.
University of Chittagong

2. Numerical Aperture, NA
 There is a relationship between the
acceptance angle and refractive
indices of the three media- core,
cladding and air.
 This leads to the definition of a more
generally used term, the NA of the
fiber.

3. Derivation of NA
Fig-1 shows a light ray incident on the
fiber core at an angle,𝚹1 to the fiber
axis which is less than the acceptance
angle for the fiber, 𝚹a. The ray enters
the fiber from air of the refractive
index, n0 & the fiber core has refractive
index of n1.

4. Continue..

5. Continue
A
B
C
𝛷
𝛳290

6. Continue

7. Continue
𝛷

8. Continue
𝛷

9. Example

13. Thank you all!