Optical Fibre

Optical Fibre

### Numerical Aperture

$$NA=\sqrt{\mu_1^2-\mu_2^2}$$

### Terminologies

- NA → Numerical aperture.

- μ1 → Refractive index of core.

- μ2 → Refractive index of cladding.

### Conditions / Special Cases

For total internal reflection:

$$\mu_1>\mu_2$$

### Usage

- Used in optical fibre calculations.