What is Acceptance Angle for an optical fiber?
For a Solar concentrator, the Acceptance angle is the maximum angel at which the incident sunlight is all captured by the concentrator. Since light is used for transmission of information through an optical fiber, acceptance angle should be applicable to the glass fibers too. How does the acceptance angle affects light injection to the fiber? Or is it important at all for an optical fiber?
For optical fibers also, the concept is the same. It is the maximum angle at which the light can be injected into an optical fiber so that the total internal reflection will happen. Total Internal Reflection is a phenomenon by which the light propagates along the length of an optical fiber.
Acceptance angle in an optical fiber is defined as the half-angle of the cone (α) within which incident light is totally internally reflected by the fiber core. Mathematically, the acceptance angle is expressed as sin^-1(NA) (Arcsine (NA), where NA is the Numerical Aperture.
n0 is the refractive index of the immediate surrounding of optical fiber. Usually, this is air and the value is 1.
n1 is the refractive index of the Core
n2 is the refractive index of the Cladding