Define Acceptance angle and Numerical Aperture, and derive an expression for NA in terms of refractive indices of core, cladding, and surroundings.
Answer:-
Acceptance Angle and Numerical Aperture
Acceptance Angle (θ₀):
The acceptance angle is the maximum angle of incidence (with respect to the fiber axis) at which light can enter the optical fiber and still be guided through total internal reflection within the core.
Numerical Aperture (NA):
The numerical aperture is a dimensionless number that describes the light-gathering ability of an optical fiber. It is related to the maximum acceptance angle:
Derive an expression for NA in terms of refractive indices of core, cladding, and surroundings.
